WO2020105143A1 - Optical spatial communication device and optical spatial communication method - Google Patents

Optical spatial communication device and optical spatial communication method

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Publication number
WO2020105143A1
WO2020105143A1 PCT/JP2018/042999 JP2018042999W WO2020105143A1 WO 2020105143 A1 WO2020105143 A1 WO 2020105143A1 JP 2018042999 W JP2018042999 W JP 2018042999W WO 2020105143 A1 WO2020105143 A1 WO 2020105143A1
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WO
WIPO (PCT)
Prior art keywords
optical
signal
communication
data
space communication
Prior art date
Application number
PCT/JP2018/042999
Other languages
French (fr)
Japanese (ja)
Inventor
俊行 安藤
英介 原口
麻菜 細川
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2018/042999 priority Critical patent/WO2020105143A1/en
Priority to JP2020557082A priority patent/JP6884290B2/en
Publication of WO2020105143A1 publication Critical patent/WO2020105143A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum

Definitions

  • the present invention relates to an optical space communication device and an optical space communication method for performing optical space communication of optical signals.
  • Patent Document 1 includes a hybrid communication station including an optical transceiver that performs data communication using an optical signal and an RF transceiver that performs data communication using a radio frequency (hereinafter referred to as “RF”) signal. Is disclosed.
  • the hybrid communication station disclosed in Patent Document 1 monitors the optical power level of an optical signal transmitted from a communication partner. If the optical power level is not degraded, the optical transceiver uses the optical signal to perform data communication. If the optical power level has deteriorated, the RF transceiver uses the RF signal to perform data communication.
  • RF radio frequency
  • the hybrid communication station disclosed in Patent Document 1 if the optical power level of the optical signal transmitted from the communication partner is deteriorated, the RF transceiver performs data communication using the RF signal. Therefore, the hybrid communication station can continue the data communication even if the communication quality of the optical signal deteriorates for some reason.
  • the data communication of the RF signal has a lower communication rate than the data communication of the optical signal, but the communication quality of the RF signal does not deteriorate due to changes in weather conditions and the like, and therefore the reliability of the data communication of the RF signal is high.
  • the hybrid communication station disclosed in Patent Document 1 merely monitors the optical power level of the optical signal, it cannot specify the cause of the deterioration of the communication quality of the optical signal. There were challenges.
  • the present invention has been made to solve the above problems, and an object thereof is to obtain an optical space communication device and an optical space communication method capable of identifying an abnormal factor of optical space communication.
  • An optical space communication device includes an optical transceiver for performing optical space communication of an optical signal including an identification signal and communication data, a radio frequency transceiver for performing radio frequency spatial communication of a radio frequency signal including communication data, and an optical transceiver. After the optical signal is transmitted from the optical transceiver, it is determined whether the optical space communication is normal based on the temporal change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver. If the optical free space communication is abnormal, a determination unit for determining an abnormal cause of the free space optical communication is provided based on the time change of the signal strength.
  • the determination unit after the optical signal is transmitted from the optical transceiver, based on the time change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver,
  • the optical space communication device is configured to determine whether the optical space communication is normal and, if the optical space communication is abnormal, to determine the cause of the optical space communication abnormality based on the temporal change of the signal strength. did. Therefore, the optical free space communication apparatus according to the present invention can identify an abnormal cause of free space optical communication.
  • FIG. 1 is a configuration diagram showing an optical space communication device according to a first embodiment.
  • 5 is a configuration diagram showing a time-series signal processing unit 34 of the optical space communication device according to the first embodiment.
  • FIG. 3 is a hardware configuration diagram showing hardware of a data extraction unit 68, a Fourier transform unit 70, a signal strength calculation processing unit 71, and a time change data generation unit 72.
  • FIG. 10 is a hardware configuration diagram of a computer when a part of the time-series signal processing unit 34 is realized by software, firmware, or the like.
  • FIG. 3 is a configuration diagram showing a determination unit 51 of the optical space communication device according to the first embodiment.
  • FIG. 3 is a hardware configuration diagram showing hardware of a determination unit 51 and a control unit 52 of the optical space communication device according to the first embodiment.
  • FIG. It is a hardware block diagram of a computer when the determination part 51 and the control part 52 are implement
  • 7 is an explanatory diagram showing a time-series signal output from the signal multiplexer 24, light intensity-modulated by the light intensity modulator 26, and backscattered light received by the optical receiver 33.
  • FIG. FIG. 9A is an explanatory diagram showing a spectrum of an optical signal in a period including an identification signal
  • FIG. 9B is an explanatory diagram showing a spectrum of an optical signal in a period including a modulation signal of communication data.
  • FIG. 11A is an explanatory diagram showing spectra of the backscattered lights 101 and 102.
  • FIG. 11B is an explanatory diagram showing the pass band of the LPF 65.
  • FIG. 12A is an explanatory diagram showing a fast Fourier transform result at time t 0
  • FIG. 12B is an explanatory diagram showing a fast Fourier transform result at time t 1 .
  • It is explanatory drawing which shows the time change data which show the time change of the signal strength of the identification signal corresponding to distance range (0)-(N).
  • FIG. 14A is an explanatory view showing time change data when the optical space communication is normal, and FIG.
  • FIG. 14B is a case where the optical space communication is normal and the aerosol concentration in the optical space is decreased as compared with FIG. 14A.
  • FIG. 14C is an explanatory view showing time change data when the optical space communication device shown in FIG. 1 fails and the signal strength of the optical signal output from the optical transceiver 2 is lowered.
  • FIG. 14D is an explanatory diagram showing time change data when the weather is rainfall or heavy fog
  • FIG. 14E shows time change data when an optical axis shift occurs between the transmitting side and receiving side optical space communication devices.
  • FIG. 1 is a configuration diagram showing an optical space communication device according to the first embodiment.
  • a data interface unit 1 buffers communication data for transmission, and communication data received by an optical transceiver 2 or communication received by a radio frequency (hereinafter referred to as “RF”) transceiver 3. Buffer the data.
  • the transmission buffer 11 is a memory for buffering communication data for transmission.
  • the reception buffer 12 is a memory for buffering communication data received by the optical transceiver 2 or communication data received by the RF transceiver 3.
  • the optical transceiver 2 performs optical space communication of an optical signal including an identification signal and communication data.
  • the RF transceiver 3 performs RF space communication of an RF signal including communication data.
  • the transmission switch 21 When the transmission switch 21 receives from the control unit 52 a control signal indicating that optical space communication is to be performed, the transmission switch 21 outputs the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. .. When the transmission switch 21 receives from the control unit 52 a control signal indicating that RF space communication is to be performed, the transmission switch 21 sends the transmission communication data buffered by the transmission buffer 11 to the transmission buffer 41 of the RF transceiver 3. Output to.
  • the data modulation drive circuit 22 modulates the communication data output from the transmission switch 21, and outputs a modulation signal of the communication data to the signal multiplexer 24.
  • the burst modulation drive circuit 23 periodically oscillates a trigger signal and outputs the trigger signal to the time series signal processing unit 34. Further, the burst modulation drive circuit 23 outputs an identification signal having a frequency f 0 to the signal multiplexer 24 in synchronization with the trigger signal.
  • the signal multiplexer 24 multiplexes the modulation signal including the communication data output from the data modulation driving circuit 22 (hereinafter referred to as “modulation communication data”) and the identification signal output from the burst modulation driving circuit 23.
  • the time-series signal which is a combined signal of the modulated communication data and the identification signal, is output to the optical intensity modulator 26.
  • the signal multiplexing process performed by the signal multiplexer 24 multiplexes the modulated communication data and the identification signal so that the modulated communication data and the identification signal are arranged in time series.
  • the reference light source 25 is a light source that continuously oscillates light of a single frequency.
  • the wavelength of the light emitted from the reference light source 25 is different from the wavelength of the light emitted from the reference light source included in the optical space communication device of the communication partner (not shown).
  • the configuration of the optical space communication device as a communication partner (not shown) is the same as the configuration of the optical space communication device shown in FIG.
  • the optical space communication device of the communication partner may be any device that can carry out the optical space communication of the optical signal and the RF space communication of the RF signal, and has the configuration of the optical space communication device shown in FIG. It does not have to be the same.
  • the light intensity modulator 26 intensity-modulates the light oscillated by the reference light source 25 by the time-series signal output from the signal multiplexer 24, and outputs the optical signal obtained by the intensity modulation to the storage-type optical amplifier 27.
  • the optical signal output from the light intensity modulator 26 is pulsed light.
  • the storage-type optical amplifier 27 is configured so that the amplification factor of the optical signal output from the optical intensity modulator 26 in the period including the identification signal is higher than the amplification factor in the period including the modulated communication data. ,
  • the optical signal output from the optical intensity modulator 26 is amplified.
  • the storage-type optical amplifier 27 outputs the amplified optical signal to the optical circulator 28.
  • the optical circulator 28 outputs the optical signal output from the storage-type optical amplifier 27 to the wavelength branching coupler 29, and outputs the backscattered light of the optical signal output from the wavelength branching coupler 29 to the optical receiver 33.
  • the wavelength branching coupler 29 outputs the optical signal output from the optical circulator 28 to the telescope 30.
  • the wavelength branching coupler 29 outputs the optical signal to the data communication optical receiver 31 if the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner. To do. If the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, the wavelength branching coupler 29 outputs the optical signal to the optical circulator 28.
  • the optical signal is backscattered light of the optical signal transmitted from the telescope 30.
  • the telescope 30 outputs the optical signal output from the wavelength branching coupler 29 to the optical space, thereby transmitting the optical signal to the optical space communication device of the communication partner.
  • the telescope 30 receives the optical signal transmitted from the optical space communication device of the communication partner, and also receives the backscattered light of the optical signal output to the optical space.
  • the data communication optical receiver 31 receives the optical signal output from the wavelength branching coupler 29, demodulates the communication data included in the optical signal, and outputs the communication data to the receiving switch 32.
  • the receiving switch 32 transfers the communication data output from the data communication optical receiver 31 to the receiving buffer 12 of the data interface unit 1. Output.
  • the receiving switch 32 receives the communication data buffered by the receiving buffer 44 of the RF transceiver 3 from the control unit 52 for receiving the data interface unit 1. Output to the buffer 12.
  • the optical receiver 33 receives the backscattered light output from the wavelength branching coupler 29 via the optical circulator 28, converts the backscattered light into an electric signal, and outputs the electric signal to the time-series signal processing unit 34. To do.
  • the time-series signal processing unit 34 uses the trigger signal output from the burst modulation drive circuit 23 to extract the identification signal included in the backscattered light from the electrical signal output from the optical receiver 33, and performs identification. Calculate the signal strength of the signal.
  • the time-series signal processing unit 34 stores the signal strength in the monitor buffer 35 every time the signal strength is calculated, thereby generating the time change data indicating the time change of the signal strength.
  • the monitor buffer 35 is a memory for buffering the time change data generated by the time series signal processing unit 34.
  • the transmission buffer 41 buffers the communication data output from the transmission switch 21 of the optical transceiver 2.
  • the transceiver 42 modulates the RF signal as a carrier with the communication data buffered by the transmission buffer 41 and outputs the RF signal to the transmission / reception antenna 43.
  • the transceiver 42 receives the RF signal output from the transmission / reception antenna 43, demodulates the RF signal to extract communication data, and outputs the communication data to the reception buffer 44.
  • the transmitting / receiving antenna 43 radiates the RF signal output from the transmitter / receiver 42 into the space, thereby transmitting the RF signal to the optical space communication device of the communication partner.
  • the transmitting / receiving antenna 43 receives the RF signal transmitted from the optical space communication device of the communication partner, and outputs the received RF signal to the transceiver 42.
  • the reception buffer 44 buffers the communication data output from the transceiver 42.
  • the determination unit 51 determines whether or not the optical space communication is normal based on the time change indicated by the time change data buffered by the monitor buffer 35. If the optical space communication is abnormal, the time is determined. Based on the time change indicated by the change data, the cause of abnormality in the optical space communication is determined. Abnormal factors in optical space communication include optical axis misalignment due to misalignment between the transmitting side and receiving side optical space communication devices, fluctuations in meteorological conditions, failure of the optical space communication device, or sudden communication to the communication path. Invasion of shields, etc. may be considered.
  • the determination unit 51 outputs a determination result indicating whether the optical free space communication is normal to the control unit 52.
  • the control unit 52 is realized, for example, by a control circuit 88 shown in FIG.
  • the control unit 52 enables the optical space communication and invalidates the RF space communication, and thus the control signal indicating that the optical space communication is performed. Is output to each of the transmission switch 21 and the reception switch 32. If the determination unit 51 determines that the optical space communication is abnormal, the control unit 52 enables the RF space communication and disables the optical space communication, and thus a control signal indicating that the RF space communication is performed. Is output to each of the transmission switch 21 and the reception switch 32.
  • FIG. 2 is a configuration diagram showing the time-series signal processing unit 34 of the optical space communication device according to the first embodiment.
  • the reception signal input unit 61 is a terminal for inputting an electric signal output from the optical receiver 33 as a reception signal of backscattered light.
  • the trigger signal input unit 62 is a terminal for inputting the trigger signal output from the burst modulation drive circuit 23.
  • the identification signal extraction unit 63 includes a clock generation unit 64, a low pass filter (LPF) 65 that is a low-pass filter, an ADC (Analog to Digital Converter) 66 that is an analog-digital converter, a data buffer 67, and a data extraction unit 68. I have it.
  • the identification signal extraction unit 63 blocks passage of communication data included in the backscattered light and extracts the identification signal included in the backscattered light.
  • the clock generator 64 oscillates a clock signal and outputs the clock signal to the ADC 66.
  • the LPF 65 blocks the passage of communication data included in the backscattered light and extracts the identification signal included in the backscattered light, The extracted identification signal is output to the ADC 66.
  • the ADC 66 samples the identification signal output from the LPF 65 in synchronization with the clock signal output from the clock generation unit 64, and outputs the sampling data of the identification signal to the data buffer 67.
  • the frequency of the clock signal is at least twice the frequency f 0 of the identification signal according to the sampling theorem.
  • the data buffer 67 is a memory for buffering the sampling data of the identification signal output from the ADC 66.
  • the sampling data buffered by the data buffer 67 is associated with the elapsed time from the time when the trigger signal is input from the trigger signal input unit 62.
  • the elapsed time from the time when the trigger signal is input corresponds to the distance from the telescope 30 to the position where the optical signal is scattered (hereinafter referred to as “distance range”). Therefore, the data buffer 67 stores sampling data having different distance ranges.
  • the data extraction unit 68 is realized by, for example, the data extraction circuit 81 shown in FIG.
  • the data extraction unit 68 extracts sampling data of each distance range from the data buffer 67 as an identification signal corresponding to each distance range, and outputs the extracted sampling data to the Fourier transform unit 70 of the signal strength calculation unit 69. ..
  • FIG. 3 is a hardware configuration diagram showing the hardware of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72.
  • the signal strength calculation unit 69 includes a Fourier transform unit 70 and a signal strength calculation processing unit 71, and calculates the signal strength of the identification signal extracted by the identification signal extraction unit 63.
  • the Fourier transform unit 70 is realized by, for example, the Fourier transform circuit 82 shown in FIG.
  • the Fourier transform unit 70 performs fast Fourier transform on the sampling data of each distance range extracted by the data extraction unit 68, and outputs each fast Fourier transform result to the signal strength calculation processing unit 71.
  • the signal strength calculation processing unit 71 is realized by, for example, the signal strength calculation processing circuit 83 shown in FIG.
  • the signal strength calculation processing unit 71 outputs the component of the frequency f 0 indicated by each fast Fourier transform result of the Fourier transform unit 70 to the time change data generation unit 72 as the signal strength of the identification signal corresponding to each distance range. To do.
  • the time change data generation unit 72 is realized by, for example, the time change data generation circuit 84 shown in FIG.
  • the time change data generation unit 72 stores the signal strength of the identification signal corresponding to each distance range output from the signal strength calculation processing unit 71 in the monitor buffer 35, and thus the time change indicating the time change of the signal strength. Generate data.
  • the data output unit 73 is a terminal for outputting the signal strength calculated by the time change data generation unit 72 to the monitor buffer 35.
  • each of the data extraction unit 68, the Fourier transform unit 70, the signal intensity calculation processing unit 71, and the time change data generation unit 72, which are some of the components of the time-series signal processing unit 34, are as shown in FIG. It is supposed to be realized by dedicated hardware. That is, it is assumed that a part of the time series signal processing unit 34 is realized by the data extraction circuit 81, the Fourier transform circuit 82, the signal strength calculation processing circuit 83, and the time change data generation circuit 84.
  • each of the data extraction circuit 81, the Fourier transform circuit 82, the signal strength calculation processing circuit 83, and the time change data generation circuit 84 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, An ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof is applicable.
  • Part of the time-series signal processing unit 34 is not limited to being realized by dedicated hardware, but part of the time-series signal processing unit 34 is realized by software, firmware, or a combination of software and firmware. It may be one that is done.
  • the software or firmware is stored in the memory of the computer as a program.
  • the computer means hardware that executes a program, and corresponds to, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor). To do.
  • FIG. 4 is a hardware configuration diagram of a computer when a part of the time-series signal processing unit 34 is realized by software, firmware, or the like.
  • the processing procedure of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72 is executed by the computer.
  • a program for causing the program is stored in the memory 91.
  • the processor 92 of the computer executes the program stored in the memory 91.
  • FIG. 5 is a configuration diagram showing the determination unit 51 of the optical free space communication apparatus according to the first embodiment.
  • FIG. 6 is a hardware configuration diagram showing the hardware of the determination unit 51 and the control unit 52 of the optical free space communication apparatus according to the first embodiment.
  • the data acquisition unit 51a is realized by, for example, the data acquisition circuit 85 shown in FIG.
  • the data acquisition unit 51a acquires the time change data when the optical space communication is normal and the time change data buffered by the monitor buffer 35 (hereinafter, referred to as “monitoring time change data”).
  • the data acquisition unit 51a outputs each of the time change data and the monitoring time change data when the optical space communication is normal to the signal strength comparison unit 51b.
  • the time change data when the optical space communication is normal may be stored in the internal memory of the data acquisition unit 51a or may be given from the outside.
  • the signal strength comparison unit 51b is realized by, for example, the signal strength comparison circuit 86 shown in FIG.
  • the signal strength comparison unit 51b compares the signal strength of each distance area indicated by the time change data when the optical space communication is normal with the signal strength of each distance area indicated by the monitoring time change data, and compares the signal strength of each distance area.
  • the comparison result of the signal strength is output to the determination processing unit 51c.
  • the determination processing unit 51c is realized by, for example, the determination processing circuit 87 illustrated in FIG.
  • the determination processing unit 51c determines whether or not the optical space communication is normal based on the comparison result of the signal intensities output from the signal intensity comparison unit 51b, and controls the determination result indicating whether or not the optical space communication is normal. Output to the unit 52. If the optical space communication is abnormal, the determination processing unit 51c determines an abnormal factor of the optical space communication based on the comparison result of the signal intensities output from the signal intensity comparison unit 51b.
  • each of the data acquisition unit 51a, the signal strength comparison unit 51b, and the determination processing unit 51c, which are the constituent elements of the determination unit 51 is realized by dedicated hardware as shown in FIG. There is. That is, it is assumed that the components of the determination unit 51 are realized by the data acquisition circuit 85, the signal strength comparison circuit 86, and the determination processing circuit 87. Further, it is assumed that the control unit 52 is realized by the control circuit 88 as shown in FIG.
  • each of the data acquisition circuit 85, the signal strength comparison circuit 86, the determination processing circuit 87, and the control circuit 88 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, Alternatively, a combination of these is applicable.
  • the determination unit 51 and the control unit 52 are not limited to those realized by dedicated hardware, and a part of the determination unit 51 and the control unit 52 is realized by software, firmware, or a combination of software and firmware. It may be one.
  • FIG. 7 is a hardware configuration diagram of a computer when the determination unit 51 and the control unit 52 are realized by software, firmware, or the like.
  • a program for causing a computer to execute the processing procedure of the data acquisition unit 51a, the signal strength comparison unit 51b, the determination processing unit 51c, and the control unit 52 is provided. It is stored in the memory 93. Then, the processor 94 of the computer executes the program stored in the memory 93.
  • the control unit 52 outputs a control signal instructing output of communication data to the data interface unit 1, and outputs a control signal indicating that optical space communication is to be performed, to each of the transmission switch 21 and the reception switch 32. Further, the control unit 52 outputs a control signal instructing the output of the trigger signal and the identification signal to the burst modulation drive circuit 23.
  • the transmission switch 21 When the transmission switch 21 receives from the control unit 52 a control signal indicating that optical space communication is to be performed, the transmission switch 21 outputs the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. .. When receiving the communication data from the transmission switch 21, the data modulation drive circuit 22 modulates the communication data and outputs a modulated signal of the communication data to the signal multiplexer 24.
  • the burst modulation drive circuit 23 When the burst modulation drive circuit 23 receives a control signal for instructing the output of the trigger signal and the identification signal from the control unit 52, the burst modulation drive circuit 23 repeatedly oscillates the trigger signal at a pulse repetition interval (PRI: Pulse Repetition Interval) [sec].
  • the burst modulation drive circuit 23 outputs a trigger signal to the time-series signal processing unit 34 each time the trigger signal is oscillated.
  • the burst modulation drive circuit 23 outputs an identification signal having a time width of t 0 to the signal multiplexer 24 in synchronization with the trigger signal each time the trigger signal is oscillated.
  • the signal multiplexer 24 multiplexes the identification signal output from the burst modulation drive circuit 23 and the modulation signal of the communication data output from the data modulation drive circuit 22. As shown in FIG. 8, the signal multiplexer 24 outputs a time-series signal, which is a combined signal of the identification signal and the modulation signal of the communication data, to the optical intensity modulator 26.
  • FIG. 8 is an explanatory diagram showing a time-series signal output from the signal multiplexer 24, light intensity-modulated by the light intensity modulator 26, and backscattered light received by the optical receiver 33.
  • the reference light source 25 continuously oscillates light of a single frequency, and outputs the continuously oscillated light to the light intensity modulator 26.
  • the light intensity modulator 26 intensity-modulates the light oscillated by the reference light source 25 by the time-series signal output from the signal multiplexer 24.
  • the light intensity modulator 26 outputs an optical signal which is intensity-modulated light as shown in FIG. 8 to the storage-type optical amplifier 27.
  • the amplification factor of the optical signal output from the light intensity modulator 26 in the period of including the identification signal is larger than the amplification factor of the period in which the modulation signal of the communication data is included.
  • the optical signal output from the optical intensity modulator 26 is amplified. Since the storage-type optical amplifier 27 amplifies the optical signal, the signal level of the optical signal in the period including the identification signal becomes higher than the signal level of the optical signal in the period including the modulation signal of communication data.
  • the storage-type optical amplifier 27 outputs the amplified optical signal to the optical circulator 28.
  • the optical circulator 28 Upon receiving the optical signal from the storage-type optical amplifier 27, the optical circulator 28 outputs the optical signal to the wavelength branching coupler 29. Upon receiving the optical signal from the optical circulator 28, the wavelength branching coupler 29 outputs the optical signal to the telescope 30. The telescope 30 outputs the optical signal output from the wavelength branching coupler 29 to the optical space, thereby transmitting the optical signal to the optical space communication device of the communication partner.
  • FIG. 9 is an explanatory diagram showing the spectrum of the optical signal transmitted from the optical transceiver 2.
  • FIG. 9A shows the spectrum of the optical signal in the period containing the identification signal
  • FIG. 9B shows the spectrum of the optical signal in the period containing the modulation signal of communication data.
  • the frequency of the identification signal is f 0
  • the frequency band of the modulation signal of the communication data is fcL to fcH
  • the frequency of the modulation signal of the communication data is higher than the frequency f 0 of the identification signal.
  • the period t including the identification signal is (i ⁇ PRI) ⁇ t ⁇ (i ⁇ PRI) + t 0
  • FIG. 10 is an explanatory diagram showing the optical signal transmitted from the optical transceiver 2 and the backscattered light of the optical signal.
  • reference numeral 2a denotes the optical transceiver 2 of the optical space communication device shown in FIG. 1, which is referred to as the optical transceiver of its own station in FIG.
  • Reference numeral 2b is an optical transceiver 2 of an optical space communication device of a communication partner, which is referred to as an optical transceiver of a partner station in FIG.
  • the backscattered light 101 is backscattered light scattered by a soft target such as an aerosol or a raindrop existing in the light space between the own station and the partner station.
  • a soft target such as an aerosol or a raindrop existing in the light space between the own station and the partner station.
  • the backscattered light 101 is described as short-distance backscattered light.
  • the backscattered light 102 is backscattered light scattered by a hard target such as the casing of the partner station or the telescope 30 of the partner station.
  • the backscattered light 102 is described as long-distance backscattered light.
  • the signal intensity of the backscattered light 101 increases due to rainfall, heavy fog, or the like.
  • the signal intensity of the backscattered light 102 decreases due to optical axis shift between the own station and the partner station, rainfall, heavy fog, or the like.
  • the telescope 30 receives the optical signal transmitted from the optical space communication device of the communication partner, and also receives the backscattered lights 101 and 102 of the optical signal output to the optical space.
  • the optical signal having the spectrum shown in FIG. 9A and the optical signal having the spectrum shown in FIG. 9B are alternately output from the telescope 30 to the optical space.
  • the backscattered light 101 undergoes backscattering at a plurality of positions. Therefore, the backscattered light in which the plurality of backscattered light 101 having the spectrum shown in FIG. 9A and the backscattered light 102 having the spectrum shown in FIG. 9B are mixed is received by the telescope 30.
  • the wavelength branching coupler 29 outputs the optical signal to the data communication optical receiver 31 if the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner. To do.
  • the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, the optical signal is the backscattered light 101, 102.
  • the wavelength branching coupler 29 outputs the backscattered light 101, 102 received by the telescope 30 to the optical circulator 28.
  • the data communication optical receiver 31 receives the optical signal output from the wavelength branching coupler 29, and demodulates the communication data included in the optical signal.
  • the data communication optical receiver 31 outputs the demodulated communication data to the reception switch 32. Since the receiving switch 32 receives the control signal indicating that the optical space communication is performed from the control unit 52, the receiving switch of the data interface unit 1 receives the communication data output from the data communication optical receiver 31. Output to 12.
  • the reception buffer 12 buffers the communication data transmitted from the reception switch 32 and notifies the control unit 52 that the communication data has been received.
  • the optical circulator 28 receives the backscattered light 101, 102 from the optical circulator 28 and outputs the backscattered light 101, 102 to the optical receiver 33.
  • the optical receiver 33 Upon receiving the backscattered light 101, 102 from the optical circulator 28, the optical receiver 33 converts each of the backscattered light 101, 102 into an electric signal and outputs the electric signal to the time-series signal processing unit 34.
  • the time-series signal processing unit 34 uses the trigger signal output from the burst modulation drive circuit 23 every time it receives an electrical signal from the optical receiver 33, and the electrical signal is included in the backscattered lights 101 and 102. Each identification signal is extracted, and the signal strength of each identification signal is calculated. The time-series signal processing unit 34 stores the signal strength in the monitor buffer 35 every time the signal strength is calculated, thereby generating the time change data indicating the time change of the signal strength.
  • the process of generating time-varying data by the time-series signal processing unit 34 will be specifically described.
  • the clock generator 64 oscillates a clock signal and outputs the clock signal to the ADC 66.
  • the reception signal input unit 61 receives the electric signals corresponding to the backscattered lights 101 and 102 from the optical receiver 33, and outputs the electric signals to the LPF 65.
  • FIG. 11A is an explanatory diagram showing spectra of the backscattered lights 101 and 102.
  • FIG. 11B is an explanatory diagram showing the pass band of the LPF 65.
  • the cutoff frequency f LPF of the LPF 65 is in the range of f 0 ⁇ f LPF ⁇ fcL.
  • the LPF 65 When receiving the respective electric signals from the reception signal input unit 61, the LPF 65 blocks passage of the communication data included in the backscattered lights 101 and 102, as shown in FIG. 11B, and the backscattered lights 101 and 102. Each identification signal included in is extracted. The LPF 65 outputs each extracted identification signal to the ADC 66.
  • the ADC 66 Upon receiving the clock signal from the clock generator 64, the ADC 66 samples each identification signal output from the LPF 65 in synchronization with the clock signal, and outputs the sampling data of the identification signal to the data buffer 67.
  • the data buffer 67 buffers the sampling data of the identification signal output from the ADC 66.
  • the sampling data buffered by the data buffer 67 is associated with the elapsed time from the time when the trigger signal is input from the trigger signal input unit 62. Further, the elapsed time from the time when the trigger signal is input corresponds to the distance range. Therefore, the data buffer 67 stores sampling data having different distance ranges.
  • L 1 (c ⁇ t 1 ) / 2 [m]
  • L N (c ⁇ t N ) / 2 [m]
  • the Fourier transform unit 70 performs fast Fourier transform on the sampling data of each distance range extracted by the data extracting unit 68.
  • FIG. 12A is an explanatory diagram showing a fast Fourier transform result at time t 0
  • FIG. 12B is an explanatory diagram showing a fast Fourier transform result at time t 1 . Since the modulated signal of the communication data included in the backscattered lights 101 and 102 is removed by the LPF 65, the fast Fourier transform result includes only the spectrum of the identification signal of the frequency f 0 .
  • the frequency f 0 component shown in FIG. 12A is the signal strength of the identification signal corresponding to the distance range (0), and the frequency f 0 component shown in FIG. 12B is the signal of the identification signal corresponding to the distance range (1). Strength.
  • the signal strength calculation processing unit 71 uses the component of the frequency f 0 indicated by each fast Fourier transform result of the Fourier transform unit 70 as the signal strength of the identification signal corresponding to the distance range (0) to (N), and changes with time. Output to the generation unit 72.
  • the time change data generation unit 72 stores the signal strength of the identification signal corresponding to the distance range (0) to (N) output from the signal strength calculation processing unit 71 in the monitor buffer 35 via the data output unit 73. By doing so, the time change data indicating the time change of the signal strength is generated.
  • FIG. 13 is an explanatory diagram showing time change data showing a time change of the signal strength of the identification signal corresponding to the distance range (0) to (N). In FIG.
  • FIG. 14 is an explanatory diagram showing the relationship between the state of communication quality of optical signals and time-varying data.
  • FIG. 14A is an explanatory diagram showing time change data when the optical free space communication is normal.
  • 111 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target, which is the signal intensity in the near distance region when the optical space communication is normal.
  • 111a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0).
  • Reference numeral 112 denotes the signal strength of the identification signal included in the backscattered light 102 scattered by the hard target, which is the signal strength in the long-distance region when the optical space communication is normal.
  • FIG. 14B is an explanatory diagram showing time change data when the optical space communication is normal and the aerosol concentration in the optical space decreases as compared with FIG. 14A.
  • 113 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target.
  • 113a is a signal intensity of the identification signal included in the backscattered light 101 in a very close distance region such as a distance range (0).
  • the signal intensities 113 and 113a are lower than the signal intensities 111 and 111a, respectively, because the aerosol concentration in the optical space is decreased.
  • 114 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal intensity 114 is the same value as the signal intensity 112 even if the aerosol concentration in the light space is decreasing.
  • FIG. 14C is an explanatory diagram showing time change data when the optical space communication device shown in FIG. 1 fails and the signal strength of the optical signal output from the optical transceiver 2 decreases.
  • 115 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target, and is the near distance region when the signal level of the optical signal output from the optical transceiver 2 is lowered.
  • Signal strength at. 115a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0).
  • the signal strengths 115 and 115a are lower than the signal strengths 111 and 111a because the signal strength of the optical signal output from the optical transceiver 2 is lower.
  • 116 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. Since the signal strength of the optical signal output from the optical transceiver 2 is lowered, the signal strength 116 is also lower than the signal strength 112.
  • FIG. 14D is an explanatory diagram showing time change data when the weather is rainfall or heavy fog.
  • 117 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target.
  • 117a is a signal intensity of the identification signal included in the backscattered light 101 in a very close distance region such as a distance range (0).
  • the optical signal output from the optical transceiver 2 is scattered by raindrops and the like, so that the signal strength 117a in the extremely close distance region such as the distance range (0) is larger than the signal strength 111a. is doing.
  • the signal strength 117 in the close distance region tends to be lower than the signal strength 111.
  • 118 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal strength 118 is also lower than the signal strength 112.
  • FIG. 14E is an explanatory diagram showing time change data when an optical axis shift occurs between the transmitting side and receiving side optical space communication devices.
  • 119 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target.
  • 119a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0).
  • the signal strengths 119 and 119a of the identification signals have the same values as the signal strengths 111 and 111a even if the optical axis shift occurs.
  • 120 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal intensity 120 is smaller than the signal intensity 112 because the optical axis shift occurs.
  • FIG. 14F is an explanatory diagram showing time change data when a shield enters the transmission path in the optical space.
  • 121 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target.
  • 121a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0).
  • 122 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the shield in the transmission path.
  • the optical signal output from the optical transceiver 2 is scattered by the shield to generate a peak.
  • the signal intensity 122 is the signal intensity of the peak generated by being scattered by the shield, and is higher than the signal intensity 111.
  • the optical signal output from the optical transceiver 2 is shielded by the shield, so that the signal strength 123 is smaller than the signal strengths 111 and 112.
  • the determination unit 51 acquires the time change data buffered by the monitor buffer 35. The determination unit 51 determines whether the optical free space communication is normal based on the time change indicated by the time change data, and outputs a determination result indicating whether the optical space communication is normal to the control unit 52. If the optical space communication is abnormal, the determination unit 51 determines an abnormality factor of the optical space communication based on the time change indicated by the time change data, and outputs the determination result of the abnormality factor to the control unit 52.
  • FIG. 15 is a flowchart showing the processing content of the determination unit 51.
  • the data acquisition unit 51a acquires time change data when the optical free space communication as shown in FIG. 14A is normal (step ST1 in FIG. 15).
  • the data acquisition unit 51a outputs the time change data when the optical free space communication is normal to the signal strength comparison unit 51b.
  • the signal strength comparison unit 51b recognizes the signal strengths 111, 111a, 112 of the identification signal at the normal time shown in FIG. 14A from the time change data when the optical free space communication is normal.
  • the signal strength comparison unit 51b determines that the signal strength with the largest distance range is one of the signal strengths having a peak in the time-varying data when the optical space communication is normal. , The signal strength 112 in the long-distance region is recognized. The signal strength comparison unit 51b recognizes that the signal strength having a smaller distance range than the signal strength 112 in the long distance area is the signal strength 111 in the short distance area. The signal strength comparison unit 51b recognizes that, of the signal strengths 111 in the close distance area, for example, the signal strength in the distance range (0) is the signal strength 111a in the very close distance area.
  • the data acquisition unit 51a acquires the monitoring time change data that is the time change data buffered by the monitor buffer 35 (step ST2 in FIG. 15).
  • the data acquisition unit 51a outputs the monitoring time change data to the signal strength comparison unit 51b.
  • the signal strength comparison unit 51b compares the signal strength S N in the close distance area, the signal strength S Na in the extremely close distance area, and the signal strength S F in the long distance area included in the monitoring time change data. recognize. Specifically, in the monitoring time change data, the signal strength comparison unit 51b determines that the signal strength having the largest distance range is the signal strength in the long distance area among the one or more signal strengths having peaks. Recognize as S F.
  • the signal strength comparing unit 51b recognizes that the signal strength having a smaller distance range than the signal strength S F in the long distance area is the signal strength S N in the short distance area.
  • the signal strength comparison unit 51b recognizes that the signal strength in the distance range (0) is the signal strength S Na in the extremely close distance area, of the signal strength S N in the close distance area.
  • the distance range related to the signal intensity at which the peak occurs is smaller than the distance range in which the partner station is assumed to exist. .. Then, under the circumstance, the signal intensity having a larger distance range than the distance range related to the signal intensity at which the peak is generated uniformly decreases.
  • the signal strength comparison unit 51b determines that the distance range related to the signal strength at which the peak is generated is smaller than the distance range assumed to include the partner station, and the distance range related to the signal strength at which the peak is generated. If the signal intensity with a large distance range is uniformly reduced, the signal intensity that is uniformly reduced is recognized as the signal intensity S F in the long-distance region.
  • the distance range in which the partner station is assumed to exist may be stored in the internal memory of the signal strength comparison unit 51b or may be given from the outside.
  • the signal strength comparison unit 51b outputs the signal strength 111, the signal strength 111a, and the signal strength 112 under normal conditions to the determination processing unit 51c. Further, the signal strength comparison unit 51b outputs the signal strength S N in the close distance area, the signal strength S Na in the very close distance area, and the signal strength S F in the long distance area to the determination processing unit 51c.
  • the signal strength SN in the short distance area is a signal strength corresponding to the signal strength 113, the signal strength 115, the signal strength 117, the signal strength 119, or the signal strength 121.
  • the signal strength S Na in the extremely close distance region is a signal strength corresponding to the signal strength 113a, the signal strength 115a, the signal strength 117a, the signal strength 119a, or the signal strength 121a.
  • the signal strength S F in the long-distance region is a signal strength corresponding to the signal strength 114, the signal strength 116, the signal strength 118, the signal strength 120, or the signal strength 123.
  • the determination processing unit 51c compares the signal strength 112 in the long-distance area in a normal state with the signal strength S F in the long-distance area (step ST3 in FIG. 15). If the signal strength S F is equal to or higher than the signal strength 112 (step ST3 of FIG. 15: YES), the determination processing unit 51c determines that the signal strength 111 in the close distance area and the signal strength in the close distance area are normal. It is compared with S N (step ST4 in FIG. 15). When there is a time zone in which the signal strength SN in the short distance area is equal to or higher than the signal strength 111 (step ST4 of FIG. 15: NO), the determination processing unit 51c corresponds to the situation of FIG.
  • step ST5 it is determined that the communication is normal (step ST5 in FIG. 15). If the signal strength SN in the near distance region is smaller than the signal strength 111 over the entire time (step ST4: YES in FIG. 15), the determination processing unit 51c corresponds to the situation in FIG. 14B. Although the aerosol concentration in the light space is decreasing, it is determined that the light space communication is normal (step ST6 in FIG. 15).
  • the determination processing unit 51c determines that the signal strength 111a in the extremely close distance area in the normal state and that in the extremely close distance area are normal.
  • the signal strength S Na is compared (step ST7 in FIG. 15). If the signal strength S Na in the extremely close distance region is smaller than the signal strength 111a (step ST7 of FIG. 15: small), the determination processing unit 51c corresponds to the situation of FIG. 14C, and therefore the optical space shown in FIG. It is determined that the optical space communication is abnormal due to the failure of the communication device (step ST8 in FIG. 15).
  • step ST7 of FIG. 15 If the signal strength S Na in the extremely close distance region is larger than the signal strength 111a (step ST7 of FIG. 15: when it is large), the determination processing unit 51c corresponds to the situation of FIG. It is determined that the optical space communication is abnormal (step ST9 in FIG. 15).
  • step ST9 in FIG. 15 When the signal strength S Na in the extremely close distance area has the same value as the signal strength 111 a (step ST7 in FIG. 15: the same case), the determination processing unit 51c determines that the signal strength 111 in the close distance area at the normal time is The signal strength S N in the short distance area is compared (step ST10 in FIG. 15).
  • the determination processing unit 51c In the determination of whether the signal strength S Na and the signal strength 111a have the same value, if the difference between the signal strength S Na and the signal strength 111a is less than or equal to the threshold value, the determination processing unit 51c has the same value. May be determined.
  • the threshold may be stored in the internal memory of the determination processing unit 51c or may be given from the outside.
  • step ST10 determines whether the signal strength SN in the near distance region is equal to or higher than the signal strength 111 over the entire time. If the signal strength SN in the near distance region is equal to or higher than the signal strength 111 over the entire time (step ST10: YES in FIG. 15), the determination processing unit 51c corresponds to the situation in FIG. 14E. , And it is determined that the optical space communication is abnormal due to the optical axis shift (step ST11 in FIG. 15). When there is a time zone in which the signal strength SN in the close range is equal to or less than the signal strength 111 (step ST10: NO in FIG. 15), the determination processing unit 51c corresponds to the situation of FIG. It is determined that there is an abnormality in the optical free space communication due to the intrusion of (step ST12 in FIG. 15).
  • Signal strength S N is, as a situation where there is a time period following the signal strength 111, smaller than some of the time of the signal strength S N signal strength 111, and the signal strength 122 of the larger peak than the signal strength 111 It is possible that the situation is occurring.
  • the control unit 52 enables the optical space communication and disables the RF space communication.
  • a control signal indicating that the above is performed is output to each of the transmission switch 21 and the reception switch 32.
  • the transmission switch 21 When the transmission switch 21 receives from the control unit 52 a control signal indicating that optical space communication is to be performed, the transmission switch 21 continuously transmits the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. Output.
  • the transmission switch 21 when the RF space communication is enabled and the optical space communication is disabled, when the control signal indicating that the optical space communication is performed is received from the control unit 52, the transmission switch 21 causes the transmission switch 21 to operate in the RF space. The communication is switched so that the communication is disabled and the optical space communication is enabled. Specifically, the transmission switch 21 outputs the communication data for transmission from the situation in which the communication data for transmission buffered by the transmission buffer 11 is being output to the transmission buffer 41 of the RF transceiver 3. The output is switched to the modulation drive circuit 22.
  • the receiving switch 32 When the receiving switch 32 receives the control signal indicating that the optical space communication is performed from the control unit 52, the receiving switch 32 continuously receives the communication data output from the data communication optical receiver 31 into the receiving buffer of the data interface unit 1. Output to 12.
  • the reception switch 32 when the RF space communication is enabled and the optical space communication is disabled, when the control signal indicating that the optical space communication is performed is received from the control unit 52, the reception switch 32 causes the reception space 32 to be in the RF space. The communication is switched so that the communication is disabled and the optical space communication is enabled. Specifically, the reception switch 32 outputs the communication data output from the data communication optical receiver 31 from the situation in which the communication data buffered by the reception buffer 44 is being output to the reception buffer 12. The situation is switched to output to the reception buffer 12.
  • the control unit 52 enables the RF space communication and disables the optical space communication.
  • a control signal indicating that the above is performed is output to each of the transmission switch 21 and the reception switch 32.
  • the transmission switch 21 When the transmission switch 21 receives from the control unit 52 a control signal indicating that RF space communication is to be performed, the transmission switch 21 sends the transmission communication data buffered by the transmission buffer 11 to the transmission buffer 41 of the RF transceiver 3. Output to.
  • the receiving switch 32 When receiving the control signal indicating that the RF space communication is to be performed, the receiving switch 32 receives the communication data buffered by the receiving buffer 44 of the RF transceiver 3 from the control unit 52 for receiving the data interface unit 1. Output to the buffer 12.
  • the optical transceiver 2 for performing the optical space communication of the optical signal including the identification signal and the communication data
  • the RF transceiver 3 for performing the RF space communication of the RF signal including the communication data
  • the optical transceiver 2 After the signal is transmitted, it is determined whether or not the optical space communication is normal based on the temporal change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver 2. If the optical space communication is abnormal, the optical space communication device is configured so as to include the determination unit 51 that determines the cause of the abnormality in the optical space communication based on the temporal change in the signal strength. Therefore, the optical space communication device can identify the cause of abnormality in the optical space communication.
  • the determination unit 51 determines that the optical space communication is normal, the optical space communication is enabled, the RF space communication is disabled, and the determination unit 51 determines that the optical space communication is abnormal. If it is determined that the optical space communication device is configured, the optical space communication device is configured to include the control unit 52 that enables the RF space communication and disables the optical space communication. Therefore, the optical space communication device can continue the transmission of communication data even when the optical space communication is abnormal.
  • the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner
  • the optical signal is transmitted to the optical receiver 31 for data communication.
  • the wavelength of the optical signal output by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30
  • the optical signal is provided so as to include the wavelength branching coupler 29 that outputs the optical signal to the optical circulator 28. Configured the spatial communication device. Therefore, in the optical space communication device, one telescope 30 may serve both as the reception of the optical signal transmitted from the optical space communication device of the communication partner and the reception of the backscattered light of the optical signal transmitted from the telescope 30. it can.
  • the present invention is suitable for an optical space communication device and an optical space communication method for performing optical space communication of optical signals.

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Abstract

This optical spatial communication device is provided with: an optical transceiver (2) which performs optical spatial communication of an optical signal including an identifying signal and communication data; an RF transceiver (3) which performs an RF spatial communication of an RF signal including communication data; and a determination unit (51) which, after the optical signal has been transmitted from the optical transceiver (2), determines whether the optical spatial communication is normal on the basis of a temporal change in the signal intensity of the identifying signal included in backscattered light of the optical signal received by the optical transceiver (2), and which, if the optical spatial communication is abnormal, determines the cause of abnormality in the optical spatial communication on the basis of the temporal change in signal intensity.

Description

光空間通信装置及び光空間通信方法Optical space communication device and optical space communication method
　この発明は、光信号の光空間通信を行う光空間通信装置及び光空間通信方法に関するものである。 The present invention relates to an optical space communication device and an optical space communication method for performing optical space communication of optical signals.
　以下の特許文献１には、光学信号を用いて、データ通信を行う光学トランシーバと、無線周波数（以下、「ＲＦ」と称する）信号を用いて、データ通信を行うＲＦトランシーバとを備えるハイブリッド通信局が開示されている。
　特許文献１に開示されているハイブリッド通信局は、通信相手から送信された光学信号の光学パワーレベルを監視する。光学パワーレベルが劣化していなければ、光学トランシーバが、光学信号を用いて、データ通信を行う。
　光学パワーレベルが劣化していれば、ＲＦトランシーバが、ＲＦ信号を用いて、データ通信を行う。 Patent Document 1 below includes a hybrid communication station including an optical transceiver that performs data communication using an optical signal and an RF transceiver that performs data communication using a radio frequency (hereinafter referred to as “RF”) signal. Is disclosed.
The hybrid communication station disclosed in Patent Document 1 monitors the optical power level of an optical signal transmitted from a communication partner. If the optical power level is not degraded, the optical transceiver uses the optical signal to perform data communication.
If the optical power level has deteriorated, the RF transceiver uses the RF signal to perform data communication.
特表２００３－５２０４９１号公報Japanese Patent Publication No. 2003-520491
　特許文献１に開示されているハイブリッド通信局は、通信相手から送信された光学信号の光学パワーレベルが劣化していれば、ＲＦトランシーバが、ＲＦ信号を用いて、データ通信を行う。したがって、ハイブリッド通信局は、何らかの原因で、光学信号の通信品質が低下しても、データ通信を継続することができる。ＲＦ信号のデータ通信は、光学信号のデータ通信よりも通信レートが低いが、ＲＦ信号の通信品質は、気象条件の変動等によって低下しないため、ＲＦ信号のデータ通信の信頼性は高い。
　しかし、特許文献１に開示されているハイブリッド通信局は、単に光学信号の光学パワーレベルを監視しているだけであるため、光学信号の通信品質が低下している要因を特定することができないという課題があった。 In the hybrid communication station disclosed in Patent Document 1, if the optical power level of the optical signal transmitted from the communication partner is deteriorated, the RF transceiver performs data communication using the RF signal. Therefore, the hybrid communication station can continue the data communication even if the communication quality of the optical signal deteriorates for some reason. The data communication of the RF signal has a lower communication rate than the data communication of the optical signal, but the communication quality of the RF signal does not deteriorate due to changes in weather conditions and the like, and therefore the reliability of the data communication of the RF signal is high.
However, since the hybrid communication station disclosed in Patent Document 1 merely monitors the optical power level of the optical signal, it cannot specify the cause of the deterioration of the communication quality of the optical signal. There were challenges.
　この発明は上記のような課題を解決するためになされたもので、光空間通信の異常要因を特定することができる光空間通信装置及び光空間通信方法を得ることを目的とする。 The present invention has been made to solve the above problems, and an object thereof is to obtain an optical space communication device and an optical space communication method capable of identifying an abnormal factor of optical space communication.
　この発明に係る光空間通信装置は、識別信号と通信データを含む光信号の光空間通信を行う光トランシーバと、通信データを含む無線周波数信号の無線周波数空間通信を行う無線周波数トランシーバと、光トランシーバから光信号が送信されたのち、光トランシーバにより受信された光信号の後方散乱光に含まれている識別信号における信号強度の時間変化に基づいて、光空間通信が正常であるか否かを判定し、光空間通信が異常であれば、信号強度の時間変化に基づいて、光空間通信の異常要因を判定する判定部とを備えるようにしたものである。 An optical space communication device according to the present invention includes an optical transceiver for performing optical space communication of an optical signal including an identification signal and communication data, a radio frequency transceiver for performing radio frequency spatial communication of a radio frequency signal including communication data, and an optical transceiver. After the optical signal is transmitted from the optical transceiver, it is determined whether the optical space communication is normal based on the temporal change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver. If the optical free space communication is abnormal, a determination unit for determining an abnormal cause of the free space optical communication is provided based on the time change of the signal strength.
　この発明によれば、判定部が、光トランシーバから光信号が送信されたのち、光トランシーバにより受信された光信号の後方散乱光に含まれている識別信号における信号強度の時間変化に基づいて、光空間通信が正常であるか否かを判定し、光空間通信が異常であれば、信号強度の時間変化に基づいて、光空間通信の異常要因を判定するように、光空間通信装置を構成した。したがって、この発明に係る光空間通信装置は、光空間通信の異常要因を特定することができる。 According to this invention, the determination unit, after the optical signal is transmitted from the optical transceiver, based on the time change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver, The optical space communication device is configured to determine whether the optical space communication is normal and, if the optical space communication is abnormal, to determine the cause of the optical space communication abnormality based on the temporal change of the signal strength. did. Therefore, the optical free space communication apparatus according to the present invention can identify an abnormal cause of free space optical communication.
実施の形態１に係る光空間通信装置を示す構成図である。1 is a configuration diagram showing an optical space communication device according to a first embodiment. 実施の形態１に係る光空間通信装置の時系列信号処理部３４を示す構成図である。5 is a configuration diagram showing a time-series signal processing unit 34 of the optical space communication device according to the first embodiment. FIG. データ抽出部６８、フーリエ変換部７０、信号強度算出処理部７１及び時間変化データ生成部７２のハードウェアを示すハードウェア構成図である。3 is a hardware configuration diagram showing hardware of a data extraction unit 68, a Fourier transform unit 70, a signal strength calculation processing unit 71, and a time change data generation unit 72. FIG. 時系列信号処理部３４の一部がソフトウェア又はファームウェア等で実現される場合のコンピュータのハードウェア構成図である。FIG. 10 is a hardware configuration diagram of a computer when a part of the time-series signal processing unit 34 is realized by software, firmware, or the like. 実施の形態１に係る光空間通信装置の判定部５１を示す構成図である。FIG. 3 is a configuration diagram showing a determination unit 51 of the optical space communication device according to the first embodiment. 実施の形態１に係る光空間通信装置の判定部５１及び制御部５２のハードウェアを示すハードウェア構成図である。3 is a hardware configuration diagram showing hardware of a determination unit 51 and a control unit 52 of the optical space communication device according to the first embodiment. FIG. 判定部５１及び制御部５２がソフトウェア又はファームウェア等で実現される場合のコンピュータのハードウェア構成図である。It is a hardware block diagram of a computer when the determination part 51 and the control part 52 are implement | achieved by software or firmware. 信号合波器２４から出力された時系列信号、光強度変調器２６により強度変調された光及び光受信機３３により受信された後方散乱光を示す説明図である。7 is an explanatory diagram showing a time-series signal output from the signal multiplexer 24, light intensity-modulated by the light intensity modulator 26, and backscattered light received by the optical receiver 33. FIG. 図９Ａは、識別信号を含んでいる期間の光信号のスペクトルを示す説明図、図９Ｂは、通信データの変調信号を含んでいる期間の光信号のスペクトルを示す説明図である。FIG. 9A is an explanatory diagram showing a spectrum of an optical signal in a period including an identification signal, and FIG. 9B is an explanatory diagram showing a spectrum of an optical signal in a period including a modulation signal of communication data. 光トランシーバ２から送信された光信号と、光信号の後方散乱光とを示す説明図である。It is explanatory drawing which shows the optical signal transmitted from the optical transceiver 2, and the backscattered light of an optical signal. 図１１Ａは、後方散乱光１０１，１０２のスペクトルを示す説明図である。図１１Ｂは、ＬＰＦ６５の通過帯域を示す説明図である。FIG. 11A is an explanatory diagram showing spectra of the backscattered lights 101 and 102. FIG. 11B is an explanatory diagram showing the pass band of the LPF 65. 図１２Ａは、時刻ｔ０における高速フーリエ変換結果を示す説明図、図１２Ｂは、時刻ｔ１における高速フーリエ変換結果を示す説明図である。FIG. 12A is an explanatory diagram showing a fast Fourier transform result at time t 0 , and FIG. 12B is an explanatory diagram showing a fast Fourier transform result at time t 1 . 距離レンジ（０）～（Ｎ）に対応する識別信号の信号強度の時間変化を示す時間変化データを示す説明図である。It is explanatory drawing which shows the time change data which show the time change of the signal strength of the identification signal corresponding to distance range (0)-(N). 図１４Ａは、光空間通信が正常である場合の時間変化データを示す説明図、図１４Ｂは、光空間通信が正常であり、かつ、図１４Ａと比べて、光空間におけるエアロゾル濃度が減少した場合の時間変化データを示す説明図、図１４Ｃは、図１に示す光空間通信装置が故障して、光トランシーバ２から出力された光信号の信号強度が低下した場合の時間変化データを示す説明図、図１４Ｄは、気象が降雨又は濃霧の場合の時間変化データを示す説明図、図１４Ｅは、送信側と受信側の光空間通信装置間で光軸ずれが生じている場合の時間変化データを示す説明図、図１４Ｆは、光空間の伝送路内に遮蔽物が侵入した場合の時間変化データを示す説明図である。FIG. 14A is an explanatory view showing time change data when the optical space communication is normal, and FIG. 14B is a case where the optical space communication is normal and the aerosol concentration in the optical space is decreased as compared with FIG. 14A. And FIG. 14C is an explanatory view showing time change data when the optical space communication device shown in FIG. 1 fails and the signal strength of the optical signal output from the optical transceiver 2 is lowered. FIG. 14D is an explanatory diagram showing time change data when the weather is rainfall or heavy fog, and FIG. 14E shows time change data when an optical axis shift occurs between the transmitting side and receiving side optical space communication devices. FIG. 14F and FIG. 14F are explanatory diagrams showing time change data when a shield enters the transmission path of the optical space. 判定部５１の処理内容を示すフローチャートである。6 is a flowchart showing the processing content of the determination unit 51.
　以下、この発明をより詳細に説明するために、この発明を実施するための形態について、添付の図面に従って説明する。 Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
実施の形態１．
　図１は、実施の形態１に係る光空間通信装置を示す構成図である。
　図１において、データインタフェース部１は、送信用の通信データをバッファリングし、また、光トランシーバ２により受信された通信データ又は無線周波数（以下、「ＲＦ」と称する）トランシーバ３により受信された通信データをバッファリングする。
　送信用バッファ１１は、送信用の通信データをバッファリングするためのメモリである。
　受信用バッファ１２は、光トランシーバ２により受信された通信データ又はＲＦトランシーバ３により受信された通信データをバッファリングするためのメモリである。 Embodiment 1.
FIG. 1 is a configuration diagram showing an optical space communication device according to the first embodiment.
In FIG. 1, a data interface unit 1 buffers communication data for transmission, and communication data received by an optical transceiver 2 or communication received by a radio frequency (hereinafter referred to as “RF”) transceiver 3. Buffer the data.
The transmission buffer 11 is a memory for buffering communication data for transmission.
The reception buffer 12 is a memory for buffering communication data received by the optical transceiver 2 or communication data received by the RF transceiver 3.
　光トランシーバ２は、識別信号と通信データを含む光信号の光空間通信を実施する。
　ＲＦトランシーバ３は、通信データを含むＲＦ信号のＲＦ空間通信を実施する。 The optical transceiver 2 performs optical space communication of an optical signal including an identification signal and communication data.
The RF transceiver 3 performs RF space communication of an RF signal including communication data.
　送信用スイッチ２１は、制御部５２から、光空間通信を実施する旨を示す制御信号を受けると、送信用バッファ１１によりバッファリングされている送信用の通信データをデータ変調駆動回路２２に出力する。
　送信用スイッチ２１は、制御部５２から、ＲＦ空間通信を実施する旨を示す制御信号を受けると、送信用バッファ１１によりバッファリングされている送信用の通信データをＲＦトランシーバ３の送信用バッファ４１に出力する。 When the transmission switch 21 receives from the control unit 52 a control signal indicating that optical space communication is to be performed, the transmission switch 21 outputs the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. ..
When the transmission switch 21 receives from the control unit 52 a control signal indicating that RF space communication is to be performed, the transmission switch 21 sends the transmission communication data buffered by the transmission buffer 11 to the transmission buffer 41 of the RF transceiver 3. Output to.
　データ変調駆動回路２２は、送信用スイッチ２１から出力された通信データを変調し、通信データの変調信号を信号合波器２４に出力する。
　バースト変調駆動回路２３は、周期的にトリガ信号を発振し、トリガ信号を時系列信号処理部３４に出力する。
　また、バースト変調駆動回路２３は、トリガ信号に同期して、周波数がｆ０の識別信号を信号合波器２４に出力する。
　信号合波器２４は、データ変調駆動回路２２から出力された通信データを含む変調信号（以下、「変調通信データ」と称する）と、バースト変調駆動回路２３から出力された識別信号とを合波し、変調通信データと識別信号との合波信号である時系列信号を光強度変調器２６に出力する。
　なお、信号合波器２４による信号の合波処理は、変調通信データと識別信号とが時系列で並ぶように、変調通信データと識別信号とを合波するものである。 The data modulation drive circuit 22 modulates the communication data output from the transmission switch 21, and outputs a modulation signal of the communication data to the signal multiplexer 24.
The burst modulation drive circuit 23 periodically oscillates a trigger signal and outputs the trigger signal to the time series signal processing unit 34.
Further, the burst modulation drive circuit 23 outputs an identification signal having a frequency f 0 to the signal multiplexer 24 in synchronization with the trigger signal.
The signal multiplexer 24 multiplexes the modulation signal including the communication data output from the data modulation driving circuit 22 (hereinafter referred to as “modulation communication data”) and the identification signal output from the burst modulation driving circuit 23. Then, the time-series signal, which is a combined signal of the modulated communication data and the identification signal, is output to the optical intensity modulator 26.
The signal multiplexing process performed by the signal multiplexer 24 multiplexes the modulated communication data and the identification signal so that the modulated communication data and the identification signal are arranged in time series.
　基準光源２５は、単一周波数の光を連続発振する光源である。
　基準光源２５から発振される光の波長は、図示せぬ通信相手の光空間通信装置が備える基準光源から発振される光の波長と異なる。ここでは、図示せぬ通信相手の光空間通信装置の構成は、図１に示す光空間通信装置の構成と同じであるものとする。ただし、通信相手の光空間通信装置は、光信号の光空間通信と、ＲＦ信号のＲＦ空間通信とを実施することができる装置であればよく、図１に示す光空間通信装置の構成と全く同じである必要はない。 The reference light source 25 is a light source that continuously oscillates light of a single frequency.
The wavelength of the light emitted from the reference light source 25 is different from the wavelength of the light emitted from the reference light source included in the optical space communication device of the communication partner (not shown). Here, it is assumed that the configuration of the optical space communication device as a communication partner (not shown) is the same as the configuration of the optical space communication device shown in FIG. However, the optical space communication device of the communication partner may be any device that can carry out the optical space communication of the optical signal and the RF space communication of the RF signal, and has the configuration of the optical space communication device shown in FIG. It does not have to be the same.
　光強度変調器２６は、信号合波器２４から出力された時系列信号によって基準光源２５により発振された光を強度変調し、当該強度変調により得られた光信号を蓄積型光増幅器２７に出力する。光強度変調器２６から出力される光信号は、パルス光である。
　蓄積型光増幅器２７は、光強度変調器２６から出力された光信号のうち、変調通信データを含んでいる期間の増幅率よりも、識別信号を含んでいる期間の増幅率が大きくなるように、光強度変調器２６から出力された光信号を増幅する。
　蓄積型光増幅器２７は、増幅した光信号を光サーキュレータ２８に出力する。 The light intensity modulator 26 intensity-modulates the light oscillated by the reference light source 25 by the time-series signal output from the signal multiplexer 24, and outputs the optical signal obtained by the intensity modulation to the storage-type optical amplifier 27. To do. The optical signal output from the light intensity modulator 26 is pulsed light.
The storage-type optical amplifier 27 is configured so that the amplification factor of the optical signal output from the optical intensity modulator 26 in the period including the identification signal is higher than the amplification factor in the period including the modulated communication data. , The optical signal output from the optical intensity modulator 26 is amplified.
The storage-type optical amplifier 27 outputs the amplified optical signal to the optical circulator 28.
　光サーキュレータ２８は、蓄積型光増幅器２７から出力された光信号を波長分岐カプラ２９に出力し、波長分岐カプラ２９から出力された光信号の後方散乱光を光受信機３３に出力する。
　波長分岐カプラ２９は、光サーキュレータ２８から出力された光信号を望遠鏡３０に出力する。
　波長分岐カプラ２９は、望遠鏡３０により受信された光信号の波長が、通信相手の光空間通信装置から送信された光信号の波長であれば、当該光信号をデータ通信用光受信機３１に出力する。
　波長分岐カプラ２９は、望遠鏡３０により受信された光信号の波長が、望遠鏡３０から送信された光信号の波長であれば、当該光信号を光サーキュレータ２８に出力する。当該光信号は、望遠鏡３０から送信された光信号の後方散乱光である。
　望遠鏡３０は、波長分岐カプラ２９から出力された光信号を光空間に出力することで、光信号を通信相手の光空間通信装置に送信する。
　また、望遠鏡３０は、通信相手の光空間通信装置から送信された光信号を受信するほか、光空間に出力した光信号の後方散乱光を受信する。 The optical circulator 28 outputs the optical signal output from the storage-type optical amplifier 27 to the wavelength branching coupler 29, and outputs the backscattered light of the optical signal output from the wavelength branching coupler 29 to the optical receiver 33.
The wavelength branching coupler 29 outputs the optical signal output from the optical circulator 28 to the telescope 30.
The wavelength branching coupler 29 outputs the optical signal to the data communication optical receiver 31 if the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner. To do.
If the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, the wavelength branching coupler 29 outputs the optical signal to the optical circulator 28. The optical signal is backscattered light of the optical signal transmitted from the telescope 30.
The telescope 30 outputs the optical signal output from the wavelength branching coupler 29 to the optical space, thereby transmitting the optical signal to the optical space communication device of the communication partner.
Moreover, the telescope 30 receives the optical signal transmitted from the optical space communication device of the communication partner, and also receives the backscattered light of the optical signal output to the optical space.
　データ通信用光受信機３１は、波長分岐カプラ２９から出力された光信号を受信して、光信号に含まれている通信データを復調し、通信データを受信用スイッチ３２に出力する。
　受信用スイッチ３２は、制御部５２から、光空間通信を実施する旨を示す制御信号を受けると、データ通信用光受信機３１から出力された通信データをデータインタフェース部１の受信用バッファ１２に出力する。
　受信用スイッチ３２は、制御部５２から、ＲＦ空間通信を実施する旨を示す制御信号を受けると、ＲＦトランシーバ３の受信用バッファ４４によりバッファリングされている通信データをデータインタフェース部１の受信用バッファ１２に出力する。 The data communication optical receiver 31 receives the optical signal output from the wavelength branching coupler 29, demodulates the communication data included in the optical signal, and outputs the communication data to the receiving switch 32.
When receiving the control signal indicating that the optical space communication is performed from the control unit 52, the receiving switch 32 transfers the communication data output from the data communication optical receiver 31 to the receiving buffer 12 of the data interface unit 1. Output.
When receiving the control signal indicating that the RF space communication is to be performed, the receiving switch 32 receives the communication data buffered by the receiving buffer 44 of the RF transceiver 3 from the control unit 52 for receiving the data interface unit 1. Output to the buffer 12.
　光受信機３３は、光サーキュレータ２８を介して、波長分岐カプラ２９から出力された後方散乱光を受信して、後方散乱光を電気信号に変換し、電気信号を時系列信号処理部３４に出力する。
　時系列信号処理部３４は、バースト変調駆動回路２３から出力されたトリガ信号を用いて、光受信機３３から出力された電気信号から、後方散乱光に含まれている識別信号を抽出し、識別信号の信号強度を算出する。
　時系列信号処理部３４は、信号強度を算出する毎に、信号強度をモニタ用バッファ３５に保存することで、信号強度の時間変化を示す時間変化データを生成する。
　モニタ用バッファ３５は、時系列信号処理部３４により生成された時間変化データをバッファリングするためのメモリである。 The optical receiver 33 receives the backscattered light output from the wavelength branching coupler 29 via the optical circulator 28, converts the backscattered light into an electric signal, and outputs the electric signal to the time-series signal processing unit 34. To do.
The time-series signal processing unit 34 uses the trigger signal output from the burst modulation drive circuit 23 to extract the identification signal included in the backscattered light from the electrical signal output from the optical receiver 33, and performs identification. Calculate the signal strength of the signal.
The time-series signal processing unit 34 stores the signal strength in the monitor buffer 35 every time the signal strength is calculated, thereby generating the time change data indicating the time change of the signal strength.
The monitor buffer 35 is a memory for buffering the time change data generated by the time series signal processing unit 34.
　送信用バッファ４１は、光トランシーバ２の送信用スイッチ２１から出力された通信データをバッファリングする。
　送受信機４２は、送信用バッファ４１によりバッファリングされている通信データによって、キャリアとしてのＲＦ信号を変調して、ＲＦ信号を送受信アンテナ４３に出力する。
　送受信機４２は、送受信アンテナ４３から出力されたＲＦ信号を受信し、ＲＦ信号を復調して通信データを抽出し、通信データを受信用バッファ４４に出力する。
　送受信アンテナ４３は、送受信機４２から出力されたＲＦ信号を空間に放射することで、ＲＦ信号を通信相手の光空間通信装置に送信する。
　送受信アンテナ４３は、通信相手の光空間通信装置から送信されたＲＦ信号を受信し、受信したＲＦ信号を送受信機４２に出力する。
　受信用バッファ４４は、送受信機４２から出力された通信データをバッファリングする。 The transmission buffer 41 buffers the communication data output from the transmission switch 21 of the optical transceiver 2.
The transceiver 42 modulates the RF signal as a carrier with the communication data buffered by the transmission buffer 41 and outputs the RF signal to the transmission / reception antenna 43.
The transceiver 42 receives the RF signal output from the transmission / reception antenna 43, demodulates the RF signal to extract communication data, and outputs the communication data to the reception buffer 44.
The transmitting / receiving antenna 43 radiates the RF signal output from the transmitter / receiver 42 into the space, thereby transmitting the RF signal to the optical space communication device of the communication partner.
The transmitting / receiving antenna 43 receives the RF signal transmitted from the optical space communication device of the communication partner, and outputs the received RF signal to the transceiver 42.
The reception buffer 44 buffers the communication data output from the transceiver 42.
　判定部５１は、モニタ用バッファ３５によりバッファリングされている時間変化データが示す時間変化に基づいて、光空間通信が正常であるか否かを判定し、光空間通信が異常であれば、時間変化データが示す時間変化に基づいて、光空間通信の異常要因を判定する。光空間通信の異常要因としては、送信側と受信側の光空間通信装置間の位置ずれ等に伴う光軸ずれ、気象条件の変動、光空間通信装置の故障、あるいは、通信路に対する突発的な遮蔽物の侵入等が考えられる。
　判定部５１は、光空間通信が正常であるか否かを示す判定結果を制御部５２に出力する。
　制御部５２は、例えば、後述の図６に示す制御回路８８によって実現される。
　制御部５２は、判定部５１により光空間通信が正常であると判定されれば、光空間通信を有効にして、ＲＦ空間通信を無効にするため、光空間通信を実施する旨を示す制御信号を送信用スイッチ２１及び受信用スイッチ３２のそれぞれに出力する。
　制御部５２は、判定部５１により光空間通信が異常であると判定されれば、ＲＦ空間通信を有効にして、光空間通信を無効にするため、ＲＦ空間通信を実施する旨を示す制御信号を送信用スイッチ２１及び受信用スイッチ３２のそれぞれに出力する。 The determination unit 51 determines whether or not the optical space communication is normal based on the time change indicated by the time change data buffered by the monitor buffer 35. If the optical space communication is abnormal, the time is determined. Based on the time change indicated by the change data, the cause of abnormality in the optical space communication is determined. Abnormal factors in optical space communication include optical axis misalignment due to misalignment between the transmitting side and receiving side optical space communication devices, fluctuations in meteorological conditions, failure of the optical space communication device, or sudden communication to the communication path. Invasion of shields, etc. may be considered.
The determination unit 51 outputs a determination result indicating whether the optical free space communication is normal to the control unit 52.
The control unit 52 is realized, for example, by a control circuit 88 shown in FIG. 6 described later.
If the determination unit 51 determines that the optical space communication is normal, the control unit 52 enables the optical space communication and invalidates the RF space communication, and thus the control signal indicating that the optical space communication is performed. Is output to each of the transmission switch 21 and the reception switch 32.
If the determination unit 51 determines that the optical space communication is abnormal, the control unit 52 enables the RF space communication and disables the optical space communication, and thus a control signal indicating that the RF space communication is performed. Is output to each of the transmission switch 21 and the reception switch 32.
　図２は、実施の形態１に係る光空間通信装置の時系列信号処理部３４を示す構成図である。
　図２において、受信信号入力部６１は、後方散乱光の受信信号として、光受信機３３から出力された電気信号を入力するための端子である。
　トリガ信号入力部６２は、バースト変調駆動回路２３から出力されたトリガ信号を入力するための端子である。 FIG. 2 is a configuration diagram showing the time-series signal processing unit 34 of the optical space communication device according to the first embodiment.
In FIG. 2, the reception signal input unit 61 is a terminal for inputting an electric signal output from the optical receiver 33 as a reception signal of backscattered light.
The trigger signal input unit 62 is a terminal for inputting the trigger signal output from the burst modulation drive circuit 23.
　識別信号抽出部６３は、クロック発生部６４、低域通過フィルタであるＬＰＦ（Ｌｏｗ　Ｐａｓｓ　Ｆｉｌｔｅｒ）６５、アナログデジタル変換器であるＡＤＣ（Ａｎａｌｏｇ　ｔｏ　Ｄｉｇｉｔａｌ　Ｃｏｎｖｅｒｔｅｒ）６６、データバッファ６７及びデータ抽出部６８を備えている。
　識別信号抽出部６３は、後方散乱光に含まれている通信データの通過を阻止して、後方散乱光に含まれている識別信号を抽出する。 The identification signal extraction unit 63 includes a clock generation unit 64, a low pass filter (LPF) 65 that is a low-pass filter, an ADC (Analog to Digital Converter) 66 that is an analog-digital converter, a data buffer 67, and a data extraction unit 68. I have it.
The identification signal extraction unit 63 blocks passage of communication data included in the backscattered light and extracts the identification signal included in the backscattered light.
　クロック発生部６４は、クロック信号を発振して、クロック信号をＡＤＣ６６に出力する。
　ＬＰＦ６５は、受信信号入力部６１から後方散乱光の受信信号を受けると、後方散乱光に含まれている通信データの通過を阻止して、後方散乱光に含まれている識別信号を抽出し、抽出した識別信号をＡＤＣ６６に出力する。
　ＡＤＣ６６は、クロック発生部６４から出力されたクロック信号に同期して、ＬＰＦ６５から出力された識別信号をサンプリングし、識別信号のサンプリングデータをデータバッファ６７に出力する。
　クロック信号の周波数は、サンプリング定理により、識別信号の周波数ｆ０の２倍以上とされる。 The clock generator 64 oscillates a clock signal and outputs the clock signal to the ADC 66.
Upon receiving the reception signal of the backscattered light from the reception signal input unit 61, the LPF 65 blocks the passage of communication data included in the backscattered light and extracts the identification signal included in the backscattered light, The extracted identification signal is output to the ADC 66.
The ADC 66 samples the identification signal output from the LPF 65 in synchronization with the clock signal output from the clock generation unit 64, and outputs the sampling data of the identification signal to the data buffer 67.
The frequency of the clock signal is at least twice the frequency f 0 of the identification signal according to the sampling theorem.
　データバッファ６７は、ＡＤＣ６６から出力された識別信号のサンプリングデータをバッファリングするためのメモリである。データバッファ６７によりバッファリングされているサンプリングデータは、トリガ信号入力部６２からトリガ信号が入力された時刻からの経過時間と対応付けられる。トリガ信号が入力された時刻からの経過時間は、望遠鏡３０から、光信号が散乱された位置までの距離（以下、「距離レンジ」と称する）に対応している。したがって、データバッファ６７には、距離レンジが異なるサンプリングデータが格納される。
　データ抽出部６８は、例えば、図３に示すデータ抽出回路８１によって実現される。
　データ抽出部６８は、それぞれの距離レンジに対応する識別信号として、データバッファ６７からそれぞれの距離レンジのサンプリングデータを抽出し、抽出したサンプリングデータを信号強度算出部６９のフーリエ変換部７０に出力する。
　図３は、データ抽出部６８、フーリエ変換部７０、信号強度算出処理部７１及び時間変化データ生成部７２のハードウェアを示すハードウェア構成図である。 The data buffer 67 is a memory for buffering the sampling data of the identification signal output from the ADC 66. The sampling data buffered by the data buffer 67 is associated with the elapsed time from the time when the trigger signal is input from the trigger signal input unit 62. The elapsed time from the time when the trigger signal is input corresponds to the distance from the telescope 30 to the position where the optical signal is scattered (hereinafter referred to as “distance range”). Therefore, the data buffer 67 stores sampling data having different distance ranges.
The data extraction unit 68 is realized by, for example, the data extraction circuit 81 shown in FIG.
The data extraction unit 68 extracts sampling data of each distance range from the data buffer 67 as an identification signal corresponding to each distance range, and outputs the extracted sampling data to the Fourier transform unit 70 of the signal strength calculation unit 69. ..
FIG. 3 is a hardware configuration diagram showing the hardware of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72.
　信号強度算出部６９は、フーリエ変換部７０及び信号強度算出処理部７１を備えており、識別信号抽出部６３により抽出された識別信号の信号強度を算出する。
　フーリエ変換部７０は、例えば、図３に示すフーリエ変換回路８２によって実現される。
　フーリエ変換部７０は、データ抽出部６８により抽出されたそれぞれの距離レンジのサンプリングデータをそれぞれ高速フーリエ変換し、それぞれの高速フーリエ変換結果を信号強度算出処理部７１に出力する。
　信号強度算出処理部７１は、例えば、図３に示す信号強度算出処理回路８３によって実現される。
　信号強度算出処理部７１は、フーリエ変換部７０のそれぞれの高速フーリエ変換結果が示す周波数ｆ０の成分を、それぞれの距離レンジに対応する識別信号の信号強度として、時間変化データ生成部７２に出力する。 The signal strength calculation unit 69 includes a Fourier transform unit 70 and a signal strength calculation processing unit 71, and calculates the signal strength of the identification signal extracted by the identification signal extraction unit 63.
The Fourier transform unit 70 is realized by, for example, the Fourier transform circuit 82 shown in FIG.
The Fourier transform unit 70 performs fast Fourier transform on the sampling data of each distance range extracted by the data extraction unit 68, and outputs each fast Fourier transform result to the signal strength calculation processing unit 71.
The signal strength calculation processing unit 71 is realized by, for example, the signal strength calculation processing circuit 83 shown in FIG.
The signal strength calculation processing unit 71 outputs the component of the frequency f 0 indicated by each fast Fourier transform result of the Fourier transform unit 70 to the time change data generation unit 72 as the signal strength of the identification signal corresponding to each distance range. To do.
　時間変化データ生成部７２は、例えば、図３に示す時間変化データ生成回路８４によって実現される。
　時間変化データ生成部７２は、信号強度算出処理部７１から出力されたそれぞれの距離レンジに対応する識別信号の信号強度をモニタ用バッファ３５に保存することで、信号強度の時間変化を示す時間変化データを生成する。
　データ出力部７３は、時間変化データ生成部７２により算出された信号強度をモニタ用バッファ３５に出力するための端子である。 The time change data generation unit 72 is realized by, for example, the time change data generation circuit 84 shown in FIG.
The time change data generation unit 72 stores the signal strength of the identification signal corresponding to each distance range output from the signal strength calculation processing unit 71 in the monitor buffer 35, and thus the time change indicating the time change of the signal strength. Generate data.
The data output unit 73 is a terminal for outputting the signal strength calculated by the time change data generation unit 72 to the monitor buffer 35.
　図２では、時系列信号処理部３４の構成要素の一部であるデータ抽出部６８、フーリエ変換部７０、信号強度算出処理部７１及び時間変化データ生成部７２のそれぞれが、図３に示すような専用のハードウェアで実現されるものを想定している。即ち、時系列信号処理部３４の一部が、データ抽出回路８１、フーリエ変換回路８２、信号強度算出処理回路８３及び時間変化データ生成回路８４で実現されるものを想定している。
　ここで、データ抽出回路８１、フーリエ変換回路８２、信号強度算出処理回路８３及び時間変化データ生成回路８４のそれぞれは、例えば、単一回路、複合回路、プログラム化したプロセッサ、並列プログラム化したプロセッサ、ＡＳＩＣ（Ａｐｐｌｉｃａｔｉｏｎ　Ｓｐｅｃｉｆｉｃ　Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ）、ＦＰＧＡ（Ｆｉｅｌｄ－Ｐｒｏｇｒａｍｍａｂｌｅ　Ｇａｔｅ　Ａｒｒａｙ）、又は、これらを組み合わせたものが該当する。 In FIG. 2, each of the data extraction unit 68, the Fourier transform unit 70, the signal intensity calculation processing unit 71, and the time change data generation unit 72, which are some of the components of the time-series signal processing unit 34, are as shown in FIG. It is supposed to be realized by dedicated hardware. That is, it is assumed that a part of the time series signal processing unit 34 is realized by the data extraction circuit 81, the Fourier transform circuit 82, the signal strength calculation processing circuit 83, and the time change data generation circuit 84.
Here, each of the data extraction circuit 81, the Fourier transform circuit 82, the signal strength calculation processing circuit 83, and the time change data generation circuit 84 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, An ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof is applicable.
　時系列信号処理部３４の一部は、専用のハードウェアで実現されるものに限るものではなく、時系列信号処理部３４の一部がソフトウェア、ファームウェア、又は、ソフトウェアとファームウェアとの組み合わせで実現されるものであってもよい。
　ソフトウェア又はファームウェアは、プログラムとして、コンピュータのメモリに格納される。コンピュータは、プログラムを実行するハードウェアを意味し、例えば、ＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）、中央処理装置、処理装置、演算装置、マイクロプロセッサ、マイクロコンピュータ、プロセッサ、あるいは、ＤＳＰ（Ｄｉｇｉｔａｌ　Ｓｉｇｎａｌ　Ｐｒｏｃｅｓｓｏｒ）が該当する。 Part of the time-series signal processing unit 34 is not limited to being realized by dedicated hardware, but part of the time-series signal processing unit 34 is realized by software, firmware, or a combination of software and firmware. It may be one that is done.
The software or firmware is stored in the memory of the computer as a program. The computer means hardware that executes a program, and corresponds to, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor). To do.
　図４は、時系列信号処理部３４の一部がソフトウェア又はファームウェア等で実現される場合のコンピュータのハードウェア構成図である。
　時系列信号処理部３４の一部がソフトウェア又はファームウェア等で実現される場合、データ抽出部６８、フーリエ変換部７０、信号強度算出処理部７１及び時間変化データ生成部７２の処理手順をコンピュータに実行させるためのプログラムがメモリ９１に格納される。そして、コンピュータのプロセッサ９２がメモリ９１に格納されているプログラムを実行する。 FIG. 4 is a hardware configuration diagram of a computer when a part of the time-series signal processing unit 34 is realized by software, firmware, or the like.
When a part of the time-series signal processing unit 34 is realized by software or firmware, the processing procedure of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72 is executed by the computer. A program for causing the program is stored in the memory 91. Then, the processor 92 of the computer executes the program stored in the memory 91.
　図５は、実施の形態１に係る光空間通信装置の判定部５１を示す構成図である。
　図６は、実施の形態１に係る光空間通信装置の判定部５１及び制御部５２のハードウェアを示すハードウェア構成図である。
　図５において、データ取得部５１ａは、例えば、図６に示すデータ取得回路８５によって実現される。
　データ取得部５１ａは、光空間通信が正常である場合の時間変化データと、モニタ用バッファ３５によりバッファリングされている時間変化データ（以下、「監視時間変化データ」と称する）とを取得する。
　データ取得部５１ａは、光空間通信が正常である場合の時間変化データ及び監視時間変化データのそれぞれを信号強度比較部５１ｂに出力する。
　光空間通信が正常である場合の時間変化データは、データ取得部５１ａの内部メモリに格納されているものであってもよいし、外部から与えられるものであってもよい。 FIG. 5 is a configuration diagram showing the determination unit 51 of the optical free space communication apparatus according to the first embodiment.
FIG. 6 is a hardware configuration diagram showing the hardware of the determination unit 51 and the control unit 52 of the optical free space communication apparatus according to the first embodiment.
In FIG. 5, the data acquisition unit 51a is realized by, for example, the data acquisition circuit 85 shown in FIG.
The data acquisition unit 51a acquires the time change data when the optical space communication is normal and the time change data buffered by the monitor buffer 35 (hereinafter, referred to as “monitoring time change data”).
The data acquisition unit 51a outputs each of the time change data and the monitoring time change data when the optical space communication is normal to the signal strength comparison unit 51b.
The time change data when the optical space communication is normal may be stored in the internal memory of the data acquisition unit 51a or may be given from the outside.
　信号強度比較部５１ｂは、例えば、図６に示す信号強度比較回路８６によって実現される。
　信号強度比較部５１ｂは、光空間通信が正常である場合の時間変化データが示すそれぞれの距離領域の信号強度と、監視時間変化データが示すそれぞれの距離領域の信号強度とを比較し、それぞれの信号強度の比較結果を判定処理部５１ｃに出力する。
　判定処理部５１ｃは、例えば、図６に示す判定処理回路８７によって実現される。
　判定処理部５１ｃは、信号強度比較部５１ｂから出力された信号強度の比較結果に基づいて、光空間通信が正常であるか否かを判定し、正常であるか否かを示す判定結果を制御部５２に出力する。
　判定処理部５１ｃは、光空間通信が異常であれば、信号強度比較部５１ｂから出力された信号強度の比較結果に基づいて、光空間通信の異常要因を判定する。 The signal strength comparison unit 51b is realized by, for example, the signal strength comparison circuit 86 shown in FIG.
The signal strength comparison unit 51b compares the signal strength of each distance area indicated by the time change data when the optical space communication is normal with the signal strength of each distance area indicated by the monitoring time change data, and compares the signal strength of each distance area. The comparison result of the signal strength is output to the determination processing unit 51c.
The determination processing unit 51c is realized by, for example, the determination processing circuit 87 illustrated in FIG.
The determination processing unit 51c determines whether or not the optical space communication is normal based on the comparison result of the signal intensities output from the signal intensity comparison unit 51b, and controls the determination result indicating whether or not the optical space communication is normal. Output to the unit 52.
If the optical space communication is abnormal, the determination processing unit 51c determines an abnormal factor of the optical space communication based on the comparison result of the signal intensities output from the signal intensity comparison unit 51b.
　図５では、判定部５１の構成要素であるデータ取得部５１ａ、信号強度比較部５１ｂ及び判定処理部５１ｃのそれぞれが、図６に示すような専用のハードウェアで実現されるものを想定している。即ち、判定部５１の構成要素が、データ取得回路８５、信号強度比較回路８６及び判定処理回路８７で実現されるものを想定している。
　また、制御部５２が、図６に示すような制御回路８８で実現されるものを想定している。
　ここで、データ取得回路８５、信号強度比較回路８６、判定処理回路８７及び制御回路８８のそれぞれは、例えば、単一回路、複合回路、プログラム化したプロセッサ、並列プログラム化したプロセッサ、ＡＳＩＣ、ＦＰＧＡ、又は、これらを組み合わせたものが該当する。 In FIG. 5, it is assumed that each of the data acquisition unit 51a, the signal strength comparison unit 51b, and the determination processing unit 51c, which are the constituent elements of the determination unit 51, is realized by dedicated hardware as shown in FIG. There is. That is, it is assumed that the components of the determination unit 51 are realized by the data acquisition circuit 85, the signal strength comparison circuit 86, and the determination processing circuit 87.
Further, it is assumed that the control unit 52 is realized by the control circuit 88 as shown in FIG.
Here, each of the data acquisition circuit 85, the signal strength comparison circuit 86, the determination processing circuit 87, and the control circuit 88 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, Alternatively, a combination of these is applicable.
　判定部５１及び制御部５２は、専用のハードウェアで実現されるものに限るものではなく、判定部５１及び制御部５２の一部がソフトウェア、ファームウェア、又は、ソフトウェアとファームウェアとの組み合わせで実現されるものであってもよい。
　図７は、判定部５１及び制御部５２が、ソフトウェア又はファームウェア等で実現される場合のコンピュータのハードウェア構成図である。
　判定部５１及び制御部５２が、ソフトウェア又はファームウェア等で実現される場合、データ取得部５１ａ、信号強度比較部５１ｂ、判定処理部５１ｃ及び制御部５２の処理手順をコンピュータに実行させるためのプログラムがメモリ９３に格納される。そして、コンピュータのプロセッサ９４がメモリ９３に格納されているプログラムを実行する。 The determination unit 51 and the control unit 52 are not limited to those realized by dedicated hardware, and a part of the determination unit 51 and the control unit 52 is realized by software, firmware, or a combination of software and firmware. It may be one.
FIG. 7 is a hardware configuration diagram of a computer when the determination unit 51 and the control unit 52 are realized by software, firmware, or the like.
When the determination unit 51 and the control unit 52 are realized by software or firmware, a program for causing a computer to execute the processing procedure of the data acquisition unit 51a, the signal strength comparison unit 51b, the determination processing unit 51c, and the control unit 52 is provided. It is stored in the memory 93. Then, the processor 94 of the computer executes the program stored in the memory 93.
　次に、図１に示す光空間通信装置の動作について説明する。
　初期段階では、光トランシーバ２による光信号の光空間通信が正常であるものとして説明する。
　制御部５２は、通信データの出力を指示する制御信号をデータインタフェース部１に出力し、光空間通信を実施する旨を示す制御信号を送信用スイッチ２１及び受信用スイッチ３２のそれぞれに出力する。
　また、制御部５２は、トリガ信号及び識別信号の出力を指示する制御信号をバースト変調駆動回路２３に出力する。 Next, the operation of the optical space communication device shown in FIG. 1 will be described.
In the initial stage, it is assumed that the optical space communication of the optical signal by the optical transceiver 2 is normal.
The control unit 52 outputs a control signal instructing output of communication data to the data interface unit 1, and outputs a control signal indicating that optical space communication is to be performed, to each of the transmission switch 21 and the reception switch 32.
Further, the control unit 52 outputs a control signal instructing the output of the trigger signal and the identification signal to the burst modulation drive circuit 23.
　送信用スイッチ２１は、制御部５２から、光空間通信を実施する旨を示す制御信号を受けると、送信用バッファ１１によりバッファリングされている送信用の通信データをデータ変調駆動回路２２に出力する。
　データ変調駆動回路２２は、送信用スイッチ２１から通信データを受けると、通信データを変調し、通信データの変調信号を信号合波器２４に出力する。 When the transmission switch 21 receives from the control unit 52 a control signal indicating that optical space communication is to be performed, the transmission switch 21 outputs the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. ..
When receiving the communication data from the transmission switch 21, the data modulation drive circuit 22 modulates the communication data and outputs a modulated signal of the communication data to the signal multiplexer 24.
　バースト変調駆動回路２３は、制御部５２から、トリガ信号及び識別信号の出力を指示する制御信号を受けると、パルス繰返し間隔（ＰＲＩ：Ｐｕｌｓｅ　Ｒｅｐｅｔｉｔｉｏｎ　Ｉｎｔｅｒｖａｌ）［ｓｅｃ］で、トリガ信号を繰り返し発振する。
　バースト変調駆動回路２３は、トリガ信号を発振する毎に、トリガ信号を時系列信号処理部３４に出力する。
　また、バースト変調駆動回路２３は、トリガ信号を発振する毎に、トリガ信号に同期して、ｔ０の時間幅を有する識別信号を信号合波器２４に出力する。 When the burst modulation drive circuit 23 receives a control signal for instructing the output of the trigger signal and the identification signal from the control unit 52, the burst modulation drive circuit 23 repeatedly oscillates the trigger signal at a pulse repetition interval (PRI: Pulse Repetition Interval) [sec].
The burst modulation drive circuit 23 outputs a trigger signal to the time-series signal processing unit 34 each time the trigger signal is oscillated.
Also, the burst modulation drive circuit 23 outputs an identification signal having a time width of t 0 to the signal multiplexer 24 in synchronization with the trigger signal each time the trigger signal is oscillated.
　信号合波器２４は、バースト変調駆動回路２３から出力された識別信号と、データ変調駆動回路２２から出力された通信データの変調信号とを合波する。
　信号合波器２４は、図８に示すように、識別信号と通信データの変調信号との合波信号である時系列信号を光強度変調器２６に出力する。
　図８は、信号合波器２４から出力された時系列信号、光強度変調器２６により強度変調された光及び光受信機３３により受信された後方散乱光を示す説明図である。 The signal multiplexer 24 multiplexes the identification signal output from the burst modulation drive circuit 23 and the modulation signal of the communication data output from the data modulation drive circuit 22.
As shown in FIG. 8, the signal multiplexer 24 outputs a time-series signal, which is a combined signal of the identification signal and the modulation signal of the communication data, to the optical intensity modulator 26.
FIG. 8 is an explanatory diagram showing a time-series signal output from the signal multiplexer 24, light intensity-modulated by the light intensity modulator 26, and backscattered light received by the optical receiver 33.
　基準光源２５は、単一周波数の光を連続発振し、連続発振した光を光強度変調器２６に出力する。
　光強度変調器２６は、信号合波器２４から出力された時系列信号によって基準光源２５により発振された光を強度変調する。
　光強度変調器２６は、図８に示すような強度変調した光である光信号を蓄積型光増幅器２７に出力する。 The reference light source 25 continuously oscillates light of a single frequency, and outputs the continuously oscillated light to the light intensity modulator 26.
The light intensity modulator 26 intensity-modulates the light oscillated by the reference light source 25 by the time-series signal output from the signal multiplexer 24.
The light intensity modulator 26 outputs an optical signal which is intensity-modulated light as shown in FIG. 8 to the storage-type optical amplifier 27.
　蓄積型光増幅器２７は、光強度変調器２６から出力された光信号のうち、通信データの変調信号を含んでいる期間の増幅率よりも、識別信号を含んでいる期間の増幅率が大きくなるように、光強度変調器２６から出力された光信号を増幅する。蓄積型光増幅器２７が光信号を増幅することで、識別信号を含んでいる期間の光信号の信号レベルが、通信データの変調信号を含んでいる期間の光信号の信号レベルよりも大きくなる。
　蓄積型光増幅器２７は、増幅した光信号を光サーキュレータ２８に出力する。 In the storage-type optical amplifier 27, the amplification factor of the optical signal output from the light intensity modulator 26 in the period of including the identification signal is larger than the amplification factor of the period in which the modulation signal of the communication data is included. Thus, the optical signal output from the optical intensity modulator 26 is amplified. Since the storage-type optical amplifier 27 amplifies the optical signal, the signal level of the optical signal in the period including the identification signal becomes higher than the signal level of the optical signal in the period including the modulation signal of communication data.
The storage-type optical amplifier 27 outputs the amplified optical signal to the optical circulator 28.
　光サーキュレータ２８は、蓄積型光増幅器２７から光信号を受けると、光信号を波長分岐カプラ２９に出力する。
　波長分岐カプラ２９は、光サーキュレータ２８から光信号を受けると、光信号を望遠鏡３０に出力する。
　望遠鏡３０は、波長分岐カプラ２９から出力された光信号を光空間に出力することで、光信号を通信相手の光空間通信装置に送信する。 Upon receiving the optical signal from the storage-type optical amplifier 27, the optical circulator 28 outputs the optical signal to the wavelength branching coupler 29.
Upon receiving the optical signal from the optical circulator 28, the wavelength branching coupler 29 outputs the optical signal to the telescope 30.
The telescope 30 outputs the optical signal output from the wavelength branching coupler 29 to the optical space, thereby transmitting the optical signal to the optical space communication device of the communication partner.
　図９は、光トランシーバ２から送信された光信号のスペクトルを示す説明図である。
　図９Ａは、識別信号を含んでいる期間の光信号のスペクトルを示し、図９Ｂは、通信データの変調信号を含んでいる期間の光信号のスペクトルを示している。
　識別信号の周波数は、ｆ０であり、通信データの変調信号の周波数帯域は、ｆｃＬ～ｆｃＨであり、通信データの変調信号の周波数は、識別信号の周波数ｆ０よりも高い。
　識別信号を含んでいる期間ｔは、（ｉ×ＰＲＩ）＜ｔ＜（ｉ×ＰＲＩ）＋ｔ０である。
　通信データの変調信号を含んでいる期間ｔは、（ｉ×ＰＲＩ）＋ｔ０＜ｔ＜（（ｉ＋１）×ＰＲＩ）である。ｉ＝０，１，２，・・・である。 FIG. 9 is an explanatory diagram showing the spectrum of the optical signal transmitted from the optical transceiver 2.
FIG. 9A shows the spectrum of the optical signal in the period containing the identification signal, and FIG. 9B shows the spectrum of the optical signal in the period containing the modulation signal of communication data.
The frequency of the identification signal is f 0 , the frequency band of the modulation signal of the communication data is fcL to fcH, and the frequency of the modulation signal of the communication data is higher than the frequency f 0 of the identification signal.
The period t including the identification signal is (i × PRI) <t <(i × PRI) + t 0 .
The period t including the modulated signal of the communication data is (i × PRI) + t 0 <t <((i + 1) × PRI). i = 0, 1, 2, ...
　図１０は、光トランシーバ２から送信された光信号と、光信号の後方散乱光とを示す説明図である。
　図１０において、２ａは、図１に示す光空間通信装置の光トランシーバ２であり、図１０では、自局の光トランシーバと表記している。
　２ｂは、通信相手の光空間通信装置の光トランシーバ２であり、図１０では、相手局の光トランシーバと表記している。
　後方散乱光１０１は、自局と相手局の間の光空間に存在しているエアロゾル又は雨滴等のソフトターゲットによって散乱された後方散乱光である。図１０では、後方散乱光１０１を近距離後方散乱光と表記している。
　後方散乱光１０２は、相手局の筐体又は相手局の望遠鏡３０等のハードターゲットによって散乱された後方散乱光である。図１０では、後方散乱光１０２を遠距離後方散乱光と表記している。
　後方散乱光１０１は、降雨又は濃霧等によって信号強度が増加する。
　後方散乱光１０２は、自局と相手局間での光軸ずれ、降雨又は濃霧等によって信号強度が減少する。 FIG. 10 is an explanatory diagram showing the optical signal transmitted from the optical transceiver 2 and the backscattered light of the optical signal.
In FIG. 10, reference numeral 2a denotes the optical transceiver 2 of the optical space communication device shown in FIG. 1, which is referred to as the optical transceiver of its own station in FIG.
Reference numeral 2b is an optical transceiver 2 of an optical space communication device of a communication partner, which is referred to as an optical transceiver of a partner station in FIG.
The backscattered light 101 is backscattered light scattered by a soft target such as an aerosol or a raindrop existing in the light space between the own station and the partner station. In FIG. 10, the backscattered light 101 is described as short-distance backscattered light.
The backscattered light 102 is backscattered light scattered by a hard target such as the casing of the partner station or the telescope 30 of the partner station. In FIG. 10, the backscattered light 102 is described as long-distance backscattered light.
The signal intensity of the backscattered light 101 increases due to rainfall, heavy fog, or the like.
The signal intensity of the backscattered light 102 decreases due to optical axis shift between the own station and the partner station, rainfall, heavy fog, or the like.
　望遠鏡３０は、通信相手の光空間通信装置から送信された光信号を受信するほか、光空間に出力した光信号の後方散乱光１０１，１０２を受信する。
　望遠鏡３０からは、図９Ａに示すスペクトルを有する光信号と、図９Ｂに示すスペクトルを有する光信号とが交互に光空間に出力される。また、後方散乱光１０１は、複数の位置で後方散乱を受ける。したがって、図９Ａに示すスペクトルを有する複数の後方散乱光１０１と、図９Ｂに示すスペクトルを有する後方散乱光１０２とが混在している後方散乱光が望遠鏡３０によって受信される。 The telescope 30 receives the optical signal transmitted from the optical space communication device of the communication partner, and also receives the backscattered lights 101 and 102 of the optical signal output to the optical space.
The optical signal having the spectrum shown in FIG. 9A and the optical signal having the spectrum shown in FIG. 9B are alternately output from the telescope 30 to the optical space. Further, the backscattered light 101 undergoes backscattering at a plurality of positions. Therefore, the backscattered light in which the plurality of backscattered light 101 having the spectrum shown in FIG. 9A and the backscattered light 102 having the spectrum shown in FIG. 9B are mixed is received by the telescope 30.
　波長分岐カプラ２９は、望遠鏡３０により受信された光信号の波長が、通信相手の光空間通信装置から送信された光信号の波長であれば、当該光信号をデータ通信用光受信機３１に出力する。
　望遠鏡３０により受信された光信号の波長が、望遠鏡３０から送信された光信号の波長である場合、当該光信号は、後方散乱光１０１，１０２である。この場合、波長分岐カプラ２９は、望遠鏡３０により受信された後方散乱光１０１，１０２を光サーキュレータ２８に出力する。 The wavelength branching coupler 29 outputs the optical signal to the data communication optical receiver 31 if the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner. To do.
When the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, the optical signal is the backscattered light 101, 102. In this case, the wavelength branching coupler 29 outputs the backscattered light 101, 102 received by the telescope 30 to the optical circulator 28.
　データ通信用光受信機３１は、波長分岐カプラ２９から出力された光信号を受信して、光信号に含まれている通信データを復調する。
　データ通信用光受信機３１は、復調した通信データを受信用スイッチ３２に出力する。
　受信用スイッチ３２は、制御部５２から、光空間通信を実施する旨を示す制御信号を受けているので、データ通信用光受信機３１から出力された通信データをデータインタフェース部１の受信用バッファ１２に出力する。
　受信用バッファ１２は、受信用スイッチ３２から送信された通信データをバッファリングし、通信データを受信した旨を制御部５２に通知する。 The data communication optical receiver 31 receives the optical signal output from the wavelength branching coupler 29, and demodulates the communication data included in the optical signal.
The data communication optical receiver 31 outputs the demodulated communication data to the reception switch 32.
Since the receiving switch 32 receives the control signal indicating that the optical space communication is performed from the control unit 52, the receiving switch of the data interface unit 1 receives the communication data output from the data communication optical receiver 31. Output to 12.
The reception buffer 12 buffers the communication data transmitted from the reception switch 32 and notifies the control unit 52 that the communication data has been received.
　光サーキュレータ２８は、光サーキュレータ２８から後方散乱光１０１，１０２を受けると、後方散乱光１０１，１０２を光受信機３３に出力する。
　光受信機３３は、光サーキュレータ２８から後方散乱光１０１，１０２を受けると、後方散乱光１０１，１０２のそれぞれを電気信号に変換し、それぞれの電気信号を時系列信号処理部３４に出力する。 The optical circulator 28 receives the backscattered light 101, 102 from the optical circulator 28 and outputs the backscattered light 101, 102 to the optical receiver 33.
Upon receiving the backscattered light 101, 102 from the optical circulator 28, the optical receiver 33 converts each of the backscattered light 101, 102 into an electric signal and outputs the electric signal to the time-series signal processing unit 34.
　時系列信号処理部３４は、光受信機３３から電気信号を受ける毎に、バースト変調駆動回路２３から出力されたトリガ信号を用いて、電気信号から、後方散乱光１０１，１０２に含まれているそれぞれの識別信号を抽出し、それぞれの識別信号の信号強度を算出する。
　時系列信号処理部３４は、信号強度を算出する毎に、信号強度をモニタ用バッファ３５に保存することで、信号強度の時間変化を示す時間変化データを生成する。
　以下、時系列信号処理部３４による時間変化データの生成処理を具体的に説明する。 The time-series signal processing unit 34 uses the trigger signal output from the burst modulation drive circuit 23 every time it receives an electrical signal from the optical receiver 33, and the electrical signal is included in the backscattered lights 101 and 102. Each identification signal is extracted, and the signal strength of each identification signal is calculated.
The time-series signal processing unit 34 stores the signal strength in the monitor buffer 35 every time the signal strength is calculated, thereby generating the time change data indicating the time change of the signal strength.
Hereinafter, the process of generating time-varying data by the time-series signal processing unit 34 will be specifically described.
　クロック発生部６４は、クロック信号を発振して、クロック信号をＡＤＣ６６に出力する。
　受信信号入力部６１は、図１１Ａに示すように、光受信機３３から、後方散乱光１０１，１０２のそれぞれに対応している電気信号を受けると、それぞれの電気信号をＬＰＦ６５に出力する。
　図１１Ａは、後方散乱光１０１，１０２のスペクトルを示す説明図である。
　図１１Ｂは、ＬＰＦ６５の通過帯域を示す説明図である。ＬＰＦ６５のカットオフ周波数ｆＬＰＦは、ｆ０＜ｆＬＰＦ＜ｆｃＬの範囲である。 The clock generator 64 oscillates a clock signal and outputs the clock signal to the ADC 66.
As shown in FIG. 11A, the reception signal input unit 61 receives the electric signals corresponding to the backscattered lights 101 and 102 from the optical receiver 33, and outputs the electric signals to the LPF 65.
FIG. 11A is an explanatory diagram showing spectra of the backscattered lights 101 and 102.
FIG. 11B is an explanatory diagram showing the pass band of the LPF 65. The cutoff frequency f LPF of the LPF 65 is in the range of f 0 <f LPF <fcL.
　ＬＰＦ６５は、受信信号入力部６１からそれぞれの電気信号を受けると、図１１Ｂに示すように、後方散乱光１０１，１０２に含まれている通信データの通過を阻止して、後方散乱光１０１，１０２に含まれているそれぞれの識別信号を抽出する。
　ＬＰＦ６５は、抽出したそれぞれの識別信号をＡＤＣ６６に出力する。 When receiving the respective electric signals from the reception signal input unit 61, the LPF 65 blocks passage of the communication data included in the backscattered lights 101 and 102, as shown in FIG. 11B, and the backscattered lights 101 and 102. Each identification signal included in is extracted.
The LPF 65 outputs each extracted identification signal to the ADC 66.
　ＡＤＣ６６は、クロック発生部６４からクロック信号を受けると、クロック信号に同期して、ＬＰＦ６５から出力されたそれぞれの識別信号をサンプリングし、識別信号のサンプリングデータをデータバッファ６７に出力する。
　データバッファ６７は、ＡＤＣ６６から出力された識別信号のサンプリングデータをバッファリングする。データバッファ６７によりバッファリングされているサンプリングデータは、トリガ信号入力部６２からトリガ信号が入力された時刻からの経過時間と対応付けられている。また、トリガ信号が入力された時刻からの経過時間は、距離レンジと対応している。したがって、データバッファ６７には、距離レンジが異なるサンプリングデータが格納される。 Upon receiving the clock signal from the clock generator 64, the ADC 66 samples each identification signal output from the LPF 65 in synchronization with the clock signal, and outputs the sampling data of the identification signal to the data buffer 67.
The data buffer 67 buffers the sampling data of the identification signal output from the ADC 66. The sampling data buffered by the data buffer 67 is associated with the elapsed time from the time when the trigger signal is input from the trigger signal input unit 62. Further, the elapsed time from the time when the trigger signal is input corresponds to the distance range. Therefore, the data buffer 67 stores sampling data having different distance ranges.
　データ抽出部６８は、それぞれの距離レンジに対応する識別信号として、データバッファ６７からそれぞれの距離レンジのサンプリングデータを抽出する。
　例えば、データバッファ６７によりバッファリングされているサンプリングデータのうち、望遠鏡３０からの距離がＬ０である距離レンジ（０）のサンプリングデータは、期間ｔ（ｔ０＜ｔ＜ｔ１、ｔ１＝２×ｔ０）のサンプリングデータに対応する。
　Ｌ０＝（ｃ×ｔ０）／２［ｍ］、ｃは、光速である。
　また、データバッファ６７によりバッファリングされているサンプリングデータのうち、望遠鏡３０からの距離がＬ１である距離レンジ（１）のサンプリングデータは、期間ｔ（ｔ１＜ｔ＜ｔ２、ｔ２＝３×ｔ０）のサンプリングデータに対応する。
　Ｌ１＝（ｃ×ｔ１）／２［ｍ］
　また、データバッファ６７によりバッファリングされているサンプリングデータのうち、望遠鏡３０からの距離がＬＮである距離レンジ（Ｎ）のサンプリングデータは、期間ｔ（ｔＮ＜ｔ＜ｔＮ＋１、ｔＮ＝（Ｎ＋２）×ｔ０）のサンプリングデータに対応する。
　ＬＮ＝（ｃ×ｔＮ）／２［ｍ］ The data extraction unit 68 extracts the sampling data of each distance range from the data buffer 67 as an identification signal corresponding to each distance range.
For example, among the sampling data buffered by the data buffer 67, the sampling data in the distance range (0) where the distance from the telescope 30 is L 0 is the period t (t 0 <t <t 1 , t 1 = 2 × t 0 ) of sampling data.
L 0 = (c × t 0 ) / 2 [m], where c is the speed of light.
Further, among the sampling data buffered by the data buffer 67, the sampling data in the distance range (1) where the distance from the telescope 30 is L 1 is the period t (t 1 <t <t 2 , t 2 = 3 × t 0 ) of sampling data.
L 1 = (c × t 1 ) / 2 [m]
Further, among the sampling data buffered by the data buffer 67, the sampling data in the range (N) whose distance from the telescope 30 is L N is the period t (t N <t <t N + 1 , t N = This corresponds to sampling data of (N + 2) × t 0 ).
L N = (c × t N ) / 2 [m]
　フーリエ変換部７０は、図１２に示すように、データ抽出部６８により抽出されたそれぞれの距離レンジのサンプリングデータをそれぞれ高速フーリエ変換する。
　図１２Ａは、時刻ｔ０における高速フーリエ変換結果を示す説明図であり、図１２Ｂは、時刻ｔ１における高速フーリエ変換結果を示す説明図である。
　ＬＰＦ６５によって、後方散乱光１０１，１０２により含まれている通信データの変調信号が除かれているため、高速フーリエ変換結果は、周波数ｆ０の識別信号のスペクトルだけを含んでいる。
　図１２Ａに示す周波数ｆ０の成分は、距離レンジ（０）に対応する識別信号の信号強度であり、図１２Ｂに示す周波数ｆ０の成分は、距離レンジ（１）に対応する識別信号の信号強度である。 As shown in FIG. 12, the Fourier transform unit 70 performs fast Fourier transform on the sampling data of each distance range extracted by the data extracting unit 68.
FIG. 12A is an explanatory diagram showing a fast Fourier transform result at time t 0 , and FIG. 12B is an explanatory diagram showing a fast Fourier transform result at time t 1 .
Since the modulated signal of the communication data included in the backscattered lights 101 and 102 is removed by the LPF 65, the fast Fourier transform result includes only the spectrum of the identification signal of the frequency f 0 .
The frequency f 0 component shown in FIG. 12A is the signal strength of the identification signal corresponding to the distance range (0), and the frequency f 0 component shown in FIG. 12B is the signal of the identification signal corresponding to the distance range (1). Strength.
　信号強度算出処理部７１は、フーリエ変換部７０のそれぞれの高速フーリエ変換結果が示す周波数ｆ０の成分を、距離レンジ（０）～（Ｎ）に対応する識別信号の信号強度として、時間変化データ生成部７２に出力する。
　時間変化データ生成部７２は、データ出力部７３を介して、信号強度算出処理部７１から出力された距離レンジ（０）～（Ｎ）に対応する識別信号の信号強度をモニタ用バッファ３５に保存することで、信号強度の時間変化を示す時間変化データを生成する。
　図１３は、距離レンジ（０）～（Ｎ）に対応する識別信号の信号強度の時間変化を示す時間変化データを示す説明図である。
　図１３において、例えば、ｔ＝ｔ０における識別信号の信号強度は、距離レンジ（０）に対応する識別信号の信号強度であり、ｔ＝ｔ１における識別信号の信号強度は、距離レンジ（１）に対応する識別信号の信号強度である。
　また、ｔ＝ｔＮにおける識別信号の信号強度は、距離レンジ（Ｎ）に対応する識別信号の信号強度である。 The signal strength calculation processing unit 71 uses the component of the frequency f 0 indicated by each fast Fourier transform result of the Fourier transform unit 70 as the signal strength of the identification signal corresponding to the distance range (0) to (N), and changes with time. Output to the generation unit 72.
The time change data generation unit 72 stores the signal strength of the identification signal corresponding to the distance range (0) to (N) output from the signal strength calculation processing unit 71 in the monitor buffer 35 via the data output unit 73. By doing so, the time change data indicating the time change of the signal strength is generated.
FIG. 13 is an explanatory diagram showing time change data showing a time change of the signal strength of the identification signal corresponding to the distance range (0) to (N).
In FIG. 13, for example, the signal strength of the identification signal at t = t 0 is the signal strength of the identification signal corresponding to the distance range (0), and the signal strength of the identification signal at t = t 1 is the distance range (1 ) Is the signal strength of the identification signal.
Further, the signal strength of the identification signal at t = t N is the signal strength of the identification signal corresponding to the distance range (N).
　ここで、図１４は、光学信号の通信品質の状態と時間変化データとの関係を示す説明図である。
　図１４Ａは、光空間通信が正常である場合の時間変化データを示す説明図である。
　図１４Ａにおいて、１１１は、ソフトターゲットによって散乱された後方散乱光１０１に含まれている識別信号の信号強度であり、光空間通信が正常である場合の近接距離領域での信号強度である。１１１ａは、後方散乱光１０１に含まれている識別信号の信号強度のうち、距離レンジ（０）等の極近接距離領域での信号強度である。
　１１２は、ハードターゲットによって散乱された後方散乱光１０２に含まれている識別信号の信号強度であり、光空間通信が正常である場合の遠距離領域での信号強度である。 Here, FIG. 14 is an explanatory diagram showing the relationship between the state of communication quality of optical signals and time-varying data.
FIG. 14A is an explanatory diagram showing time change data when the optical free space communication is normal.
In FIG. 14A, 111 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target, which is the signal intensity in the near distance region when the optical space communication is normal. 111a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0).
Reference numeral 112 denotes the signal strength of the identification signal included in the backscattered light 102 scattered by the hard target, which is the signal strength in the long-distance region when the optical space communication is normal.
　図１４Ｂは、光空間通信が正常であり、かつ、図１４Ａと比べて、光空間におけるエアロゾル濃度が減少した場合の時間変化データを示す説明図である。
　図１４Ｂにおいて、１１３は、ソフトターゲットによって散乱された後方散乱光１０１に含まれている識別信号の信号強度である。１１３ａは、後方散乱光１０１に含まれている識別信号の信号強度のうち、距離レンジ（０）等の極近接距離領域での信号強度である。
　信号強度１１３，１１３ａは、光空間におけるエアロゾル濃度が減少しているため、それぞれ、信号強度１１１，１１１ａよりも減少している。
　１１４は、ハードターゲットによって散乱された後方散乱光１０２に含まれている識別信号の信号強度である。信号強度１１４は、光空間におけるエアロゾル濃度が減少していても、信号強度１１２と同じ値である。 FIG. 14B is an explanatory diagram showing time change data when the optical space communication is normal and the aerosol concentration in the optical space decreases as compared with FIG. 14A.
In FIG. 14B, 113 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target. 113a is a signal intensity of the identification signal included in the backscattered light 101 in a very close distance region such as a distance range (0).
The signal intensities 113 and 113a are lower than the signal intensities 111 and 111a, respectively, because the aerosol concentration in the optical space is decreased.
114 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal intensity 114 is the same value as the signal intensity 112 even if the aerosol concentration in the light space is decreasing.
　図１４Ｃは、図１に示す光空間通信装置が故障して、光トランシーバ２から出力された光信号の信号強度が低下した場合の時間変化データを示す説明図である。
　図１４Ｃにおいて、１１５は、ソフトターゲットによって散乱された後方散乱光１０１に含まれている識別信号の信号強度であり、光トランシーバ２から出力された光信号の信号レベルが低下した場合の近接距離領域での信号強度である。１１５ａは、後方散乱光１０１に含まれている識別信号の信号強度のうち、距離レンジ（０）等の極近接距離領域での信号強度である。
　信号強度１１５，１１５ａは、光トランシーバ２から出力された光信号の信号強度が低下しているため、信号強度１１１，１１１ａよりも減少している。
　１１６は、ハードターゲットによって散乱された後方散乱光１０２に含まれている識別信号の信号強度である。光トランシーバ２から出力された光信号の信号強度が低下しているため、信号強度１１６についても、信号強度１１２よりも減少している。 FIG. 14C is an explanatory diagram showing time change data when the optical space communication device shown in FIG. 1 fails and the signal strength of the optical signal output from the optical transceiver 2 decreases.
In FIG. 14C, 115 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target, and is the near distance region when the signal level of the optical signal output from the optical transceiver 2 is lowered. Signal strength at. 115a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0).
The signal strengths 115 and 115a are lower than the signal strengths 111 and 111a because the signal strength of the optical signal output from the optical transceiver 2 is lower.
116 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. Since the signal strength of the optical signal output from the optical transceiver 2 is lowered, the signal strength 116 is also lower than the signal strength 112.
　図１４Ｄは、気象が降雨又は濃霧の場合の時間変化データを示す説明図である。
　図１４Ｄにおいて、１１７は、ソフトターゲットによって散乱された後方散乱光１０１に含まれている識別信号の信号強度である。１１７ａは、後方散乱光１０１に含まれている識別信号の信号強度のうち、距離レンジ（０）等の極近接距離領域での信号強度である。
　気象が降雨又は濃霧の場合、光トランシーバ２から出力された光信号が雨粒等に散乱されるため、距離レンジ（０）等の極近接距離領域での信号強度１１７ａは、信号強度１１１ａよりも増加している。
　ただし、近接距離領域での信号強度１１７であっても、極近接距離領域よりもハードターゲットに近い領域での信号強度１１７は、信号強度１１１よりも減少する傾向がある。
　１１８は、ハードターゲットによって散乱された後方散乱光１０２に含まれている識別信号の信号強度である。信号強度１１８についても、信号強度１１２よりも減少している。 FIG. 14D is an explanatory diagram showing time change data when the weather is rainfall or heavy fog.
In FIG. 14D, 117 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target. 117a is a signal intensity of the identification signal included in the backscattered light 101 in a very close distance region such as a distance range (0).
When the weather is rainy or dense fog, the optical signal output from the optical transceiver 2 is scattered by raindrops and the like, so that the signal strength 117a in the extremely close distance region such as the distance range (0) is larger than the signal strength 111a. is doing.
However, even with the signal strength 117 in the close distance region, the signal strength 117 in a region closer to the hard target than in the very close distance region tends to be lower than the signal strength 111.
118 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal strength 118 is also lower than the signal strength 112.
　図１４Ｅは、送信側と受信側の光空間通信装置間で光軸ずれが生じている場合の時間変化データを示す説明図である。
　図１４Ｅにおいて、１１９は、ソフトターゲットによって散乱された後方散乱光１０１に含まれている識別信号の信号強度である。１１９ａは、後方散乱光１０１に含まれている識別信号の信号強度のうち、距離レンジ（０）等の極近接距離領域での信号強度である。識別信号の信号強度１１９，１１９ａは、光軸ずれが生じていても、信号強度１１１，１１１ａと同じ値である。
　１２０は、ハードターゲットによって散乱された後方散乱光１０２に含まれている識別信号の信号強度である。信号強度１２０は、光軸ずれが生じているため、信号強度１１２よりも減少している。 FIG. 14E is an explanatory diagram showing time change data when an optical axis shift occurs between the transmitting side and receiving side optical space communication devices.
In FIG. 14E, 119 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target. 119a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0). The signal strengths 119 and 119a of the identification signals have the same values as the signal strengths 111 and 111a even if the optical axis shift occurs.
120 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal intensity 120 is smaller than the signal intensity 112 because the optical axis shift occurs.
　図１４Ｆは、光空間の伝送路内に遮蔽物が侵入した場合の時間変化データを示す説明図である。
　図１４Ｆにおいて、１２１は、ソフトターゲットによって散乱された後方散乱光１０１に含まれている識別信号の信号強度である。１２１ａは、後方散乱光１０１に含まれている識別信号の信号強度のうち、距離レンジ（０）等の極近接距離領域での信号強度である。１２２は、伝送路内の遮蔽物によって散乱された後方散乱光１０１に含まれている識別信号の信号強度である。光トランシーバ２から出力された光信号は、遮蔽物に散乱されることでピークが発生する。信号強度１２２は、遮蔽物に散乱されることで生じているピークの信号強度であり、信号強度１１１よりも増加している。
　伝送路内の遮蔽物よりも遠い距離では、光トランシーバ２から出力された光信号は、遮蔽物によって遮蔽されているため、信号強度１２３は、信号強度１１１，１１２よりも減少している。 FIG. 14F is an explanatory diagram showing time change data when a shield enters the transmission path in the optical space.
In FIG. 14F, 121 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target. 121a is a signal intensity of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0). 122 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the shield in the transmission path. The optical signal output from the optical transceiver 2 is scattered by the shield to generate a peak. The signal intensity 122 is the signal intensity of the peak generated by being scattered by the shield, and is higher than the signal intensity 111.
At a distance farther than the shield in the transmission path, the optical signal output from the optical transceiver 2 is shielded by the shield, so that the signal strength 123 is smaller than the signal strengths 111 and 112.
　判定部５１は、モニタ用バッファ３５によりバッファリングされている時間変化データを取得する。
　判定部５１は、時間変化データが示す時間変化に基づいて、光空間通信が正常であるか否かを判定し、正常であるか否かを示す判定結果を制御部５２に出力する。
　判定部５１は、光空間通信が異常であれば、時間変化データが示す時間変化に基づいて、光空間通信の異常要因を判定し、異常要因の判定結果を制御部５２に出力する。 The determination unit 51 acquires the time change data buffered by the monitor buffer 35.
The determination unit 51 determines whether the optical free space communication is normal based on the time change indicated by the time change data, and outputs a determination result indicating whether the optical space communication is normal to the control unit 52.
If the optical space communication is abnormal, the determination unit 51 determines an abnormality factor of the optical space communication based on the time change indicated by the time change data, and outputs the determination result of the abnormality factor to the control unit 52.
　図１５は、判定部５１の処理内容を示すフローチャートである。
　以下、図１５を参照しながら、判定部５１の処理内容を具体的に説明する。
　まず、データ取得部５１ａは、図１４Ａに示すような光空間通信が正常である場合の時間変化データを取得する（図１５のステップＳＴ１）。
　データ取得部５１ａは、光空間通信が正常である場合の時間変化データを信号強度比較部５１ｂに出力する。
　信号強度比較部５１ｂは、光空間通信が正常である場合の時間変化データから、図１４Ａに示す正常時における識別信号の信号強度１１１，１１１ａ，１１２を認識する。
　具体的には、信号強度比較部５１ｂは、光空間通信が正常である場合の時間変化データにおいて、ピークが発生している１つ以上の信号強度の中で、最も距離レンジが大きい信号強度が、遠距離領域での信号強度１１２であると認識する。
　信号強度比較部５１ｂは、遠距離領域での信号強度１１２に係る距離レンジよりも、距離レンジが小さい信号強度が、近接距離領域での信号強度１１１であると認識する。
　信号強度比較部５１ｂは、近接距離領域での信号強度１１１のうち、例えば、距離レンジ（０）の信号強度が、極近接距離領域での信号強度１１１ａであると認識する。 FIG. 15 is a flowchart showing the processing content of the determination unit 51.
Hereinafter, the processing content of the determination unit 51 will be specifically described with reference to FIG.
First, the data acquisition unit 51a acquires time change data when the optical free space communication as shown in FIG. 14A is normal (step ST1 in FIG. 15).
The data acquisition unit 51a outputs the time change data when the optical free space communication is normal to the signal strength comparison unit 51b.
The signal strength comparison unit 51b recognizes the signal strengths 111, 111a, 112 of the identification signal at the normal time shown in FIG. 14A from the time change data when the optical free space communication is normal.
Specifically, the signal strength comparison unit 51b determines that the signal strength with the largest distance range is one of the signal strengths having a peak in the time-varying data when the optical space communication is normal. , The signal strength 112 in the long-distance region is recognized.
The signal strength comparison unit 51b recognizes that the signal strength having a smaller distance range than the signal strength 112 in the long distance area is the signal strength 111 in the short distance area.
The signal strength comparison unit 51b recognizes that, of the signal strengths 111 in the close distance area, for example, the signal strength in the distance range (0) is the signal strength 111a in the very close distance area.
　データ取得部５１ａは、モニタ用バッファ３５によりバッファリングされている時間変化データである監視時間変化データを取得する（図１５のステップＳＴ２）。
　データ取得部５１ａは、監視時間変化データを信号強度比較部５１ｂに出力する。
　信号強度比較部５１ｂは、監視時間変化データに含まれている近接距離領域での信号強度ＳＮと、極近接距離領域での信号強度ＳＮａと、遠距離領域での信号強度ＳＦとを認識する。
　具体的には、信号強度比較部５１ｂは、監視時間変化データにおいて、ピークが発生している１つ以上の信号強度の中で、最も距離レンジが大きい信号強度が、遠距離領域での信号強度ＳＦであると認識する。
　信号強度比較部５１ｂは、遠距離領域での信号強度ＳＦに係る距離レンジよりも、距離レンジが小さい信号強度が、近接距離領域での信号強度ＳＮであると認識する。
　信号強度比較部５１ｂは、近接距離領域での信号強度ＳＮのうち、例えば、距離レンジ（０）の信号強度が、極近接距離領域での信号強度ＳＮａであると認識する。 The data acquisition unit 51a acquires the monitoring time change data that is the time change data buffered by the monitor buffer 35 (step ST2 in FIG. 15).
The data acquisition unit 51a outputs the monitoring time change data to the signal strength comparison unit 51b.
The signal strength comparison unit 51b compares the signal strength S N in the close distance area, the signal strength S Na in the extremely close distance area, and the signal strength S F in the long distance area included in the monitoring time change data. recognize.
Specifically, in the monitoring time change data, the signal strength comparison unit 51b determines that the signal strength having the largest distance range is the signal strength in the long distance area among the one or more signal strengths having peaks. Recognize as S F.
The signal strength comparing unit 51b recognizes that the signal strength having a smaller distance range than the signal strength S F in the long distance area is the signal strength S N in the short distance area.
The signal strength comparison unit 51b recognizes that the signal strength in the distance range (0) is the signal strength S Na in the extremely close distance area, of the signal strength S N in the close distance area.
　なお、光空間の伝送路内に遮蔽物が侵入している状況下では、ピークが発生している信号強度に係る距離レンジが、相手局が存在していると想定される距離レンジよりも小さい。そして、当該状況下では、ピークが発生している信号強度に係る距離レンジよりも、距離レンジが大きい信号強度が、一律に低下する。
　信号強度比較部５１ｂは、ピークが発生している信号強度に係る距離レンジが、相手局が存在していると想定される距離レンジよりも小さく、ピークが発生している信号強度に係る距離レンジよりも、距離レンジが大きい信号強度が一律に低下していれば、一律に低下している信号強度が、遠距離領域での信号強度ＳＦであると認識する。
　相手局が存在していると想定される距離レンジは、信号強度比較部５１ｂの内部メモリに格納されているものであってもよいし、外部から与えられるものであってもよい。 In addition, under the condition that a shield is invading the transmission path of the optical space, the distance range related to the signal intensity at which the peak occurs is smaller than the distance range in which the partner station is assumed to exist. .. Then, under the circumstance, the signal intensity having a larger distance range than the distance range related to the signal intensity at which the peak is generated uniformly decreases.
The signal strength comparison unit 51b determines that the distance range related to the signal strength at which the peak is generated is smaller than the distance range assumed to include the partner station, and the distance range related to the signal strength at which the peak is generated. If the signal intensity with a large distance range is uniformly reduced, the signal intensity that is uniformly reduced is recognized as the signal intensity S F in the long-distance region.
The distance range in which the partner station is assumed to exist may be stored in the internal memory of the signal strength comparison unit 51b or may be given from the outside.
　信号強度比較部５１ｂは、正常時における信号強度１１１、信号強度１１１ａ及び信号強度１１２を判定処理部５１ｃに出力する。
　また、信号強度比較部５１ｂは、近接距離領域での信号強度ＳＮ、極近接距離領域での信号強度ＳＮａ及び遠距離領域での信号強度ＳＦを判定処理部５１ｃに出力する。
　近接距離領域での信号強度ＳＮは、信号強度１１３、信号強度１１５、信号強度１１７、信号強度１１９又は信号強度１２１に対応する信号強度である。
　極近接距離領域での信号強度ＳＮａは、信号強度１１３ａ、信号強度１１５ａ、信号強度１１７ａ、信号強度１１９ａ又は信号強度１２１ａに対応する信号強度である。
　遠距離領域での信号強度ＳＦは、信号強度１１４、信号強度１１６、信号強度１１８、信号強度１２０又は信号強度１２３に対応する信号強度である。 The signal strength comparison unit 51b outputs the signal strength 111, the signal strength 111a, and the signal strength 112 under normal conditions to the determination processing unit 51c.
Further, the signal strength comparison unit 51b outputs the signal strength S N in the close distance area, the signal strength S Na in the very close distance area, and the signal strength S F in the long distance area to the determination processing unit 51c.
The signal strength SN in the short distance area is a signal strength corresponding to the signal strength 113, the signal strength 115, the signal strength 117, the signal strength 119, or the signal strength 121.
The signal strength S Na in the extremely close distance region is a signal strength corresponding to the signal strength 113a, the signal strength 115a, the signal strength 117a, the signal strength 119a, or the signal strength 121a.
The signal strength S F in the long-distance region is a signal strength corresponding to the signal strength 114, the signal strength 116, the signal strength 118, the signal strength 120, or the signal strength 123.
　判定処理部５１ｃは、正常時における遠距離領域での信号強度１１２と、遠距離領域での信号強度ＳＦとを比較する（図１５のステップＳＴ３）。
　判定処理部５１ｃは、信号強度ＳＦが信号強度１１２以上であれば（図１５のステップＳＴ３：ＹＥＳの場合）、正常時における近接距離領域での信号強度１１１と、近接距離領域での信号強度ＳＮとを比較する（図１５のステップＳＴ４）。
　判定処理部５１ｃは、近接距離領域での信号強度ＳＮが、信号強度１１１以上の時間帯がある場合（図１５のステップＳＴ４：ＮＯの場合）、図１４Ａの状況に該当するため、光空間通信が正常であると判定する（図１５のステップＳＴ５）。
　判定処理部５１ｃは、近接距離領域での信号強度ＳＮが、全ての時間に亘って信号強度１１１よりも小さければ（図１５のステップＳＴ４：ＹＥＳの場合）、図１４Ｂの状況に該当するため、光空間におけるエアロゾル濃度が減少しているものの、光空間通信は正常であると判定する（図１５のステップＳＴ６）。 The determination processing unit 51c compares the signal strength 112 in the long-distance area in a normal state with the signal strength S F in the long-distance area (step ST3 in FIG. 15).
If the signal strength S F is equal to or higher than the signal strength 112 (step ST3 of FIG. 15: YES), the determination processing unit 51c determines that the signal strength 111 in the close distance area and the signal strength in the close distance area are normal. It is compared with S N (step ST4 in FIG. 15).
When there is a time zone in which the signal strength SN in the short distance area is equal to or higher than the signal strength 111 (step ST4 of FIG. 15: NO), the determination processing unit 51c corresponds to the situation of FIG. It is determined that the communication is normal (step ST5 in FIG. 15).
If the signal strength SN in the near distance region is smaller than the signal strength 111 over the entire time (step ST4: YES in FIG. 15), the determination processing unit 51c corresponds to the situation in FIG. 14B. Although the aerosol concentration in the light space is decreasing, it is determined that the light space communication is normal (step ST6 in FIG. 15).
　判定処理部５１ｃは、信号強度ＳＦが信号強度１１２よりも小さければ（図１５のステップＳＴ３：ＮＯの場合）、正常時における極近接距離領域での信号強度１１１ａと、極近接距離領域での信号強度ＳＮａとを比較する（図１５のステップＳＴ７）。
　判定処理部５１ｃは、極近接距離領域での信号強度ＳＮａが信号強度１１１ａよりも小さければ（図１５のステップＳＴ７：小さい場合）、図１４Ｃの状況に該当するため、図１に示す光空間通信装置の故障を要因とする光空間通信の異常であると判定する（図１５のステップＳＴ８）。 If the signal strength S F is smaller than the signal strength 112 (step ST3 of FIG. 15: NO), the determination processing unit 51c determines that the signal strength 111a in the extremely close distance area in the normal state and that in the extremely close distance area are normal. The signal strength S Na is compared (step ST7 in FIG. 15).
If the signal strength S Na in the extremely close distance region is smaller than the signal strength 111a (step ST7 of FIG. 15: small), the determination processing unit 51c corresponds to the situation of FIG. 14C, and therefore the optical space shown in FIG. It is determined that the optical space communication is abnormal due to the failure of the communication device (step ST8 in FIG. 15).
　判定処理部５１ｃは、極近接距離領域での信号強度ＳＮａが信号強度１１１ａよりも大きければ（図１５のステップＳＴ７：大きい場合）、図１４Ｄの状況に該当するため、降雨又は濃霧を要因とする光空間通信の異常であると判定する（図１５のステップＳＴ９）。
　判定処理部５１ｃは、極近接距離領域での信号強度ＳＮａが信号強度１１１ａと同じ値である場合（図１５のステップＳＴ７：同じ場合）、正常時における近接距離領域での信号強度１１１と、近接距離領域での信号強度ＳＮとを比較する（図１５のステップＳＴ１０）。
　信号強度ＳＮａと信号強度１１１ａとが同じ値であるか否かの判定において、信号強度ＳＮａと信号強度１１１ａとの差分が、閾値以下であれば、判定処理部５１ｃが、同じ値であると判定するものであってもよい。閾値は、判定処理部５１ｃの内部メモリに格納されているものであってもよいし、外部から与えられるものであってもよい。 If the signal strength S Na in the extremely close distance region is larger than the signal strength 111a (step ST7 of FIG. 15: when it is large), the determination processing unit 51c corresponds to the situation of FIG. It is determined that the optical space communication is abnormal (step ST9 in FIG. 15).
When the signal strength S Na in the extremely close distance area has the same value as the signal strength 111 a (step ST7 in FIG. 15: the same case), the determination processing unit 51c determines that the signal strength 111 in the close distance area at the normal time is The signal strength S N in the short distance area is compared (step ST10 in FIG. 15).
In the determination of whether the signal strength S Na and the signal strength 111a have the same value, if the difference between the signal strength S Na and the signal strength 111a is less than or equal to the threshold value, the determination processing unit 51c has the same value. May be determined. The threshold may be stored in the internal memory of the determination processing unit 51c or may be given from the outside.
　判定処理部５１ｃは、近接距離領域での信号強度ＳＮが、全ての時間に亘って信号強度１１１以上であれば（図１５のステップＳＴ１０：ＹＥＳの場合）、図１４Ｅの状況に該当するため、光軸ずれを要因とする光空間通信の異常であると判定する（図１５のステップＳＴ１１）。
　判定処理部５１ｃは、近接距離領域での信号強度ＳＮが、信号強度１１１以下の時間帯がある場合（図１５のステップＳＴ１０：ＮＯの場合）、図１４Ｆの状況に該当するため、遮蔽物の侵入を要因とする光空間通信の異常であると判定する（図１５のステップＳＴ１２）。信号強度ＳＮが、信号強度１１１以下の時間帯がある状況としては、一部の時間の信号強度ＳＮが信号強度１１１よりも小さく、かつ、信号強度１１１よりも大きいピークの信号強度１２２が生じている状況が考えられる。 If the signal strength SN in the near distance region is equal to or higher than the signal strength 111 over the entire time (step ST10: YES in FIG. 15), the determination processing unit 51c corresponds to the situation in FIG. 14E. , And it is determined that the optical space communication is abnormal due to the optical axis shift (step ST11 in FIG. 15).
When there is a time zone in which the signal strength SN in the close range is equal to or less than the signal strength 111 (step ST10: NO in FIG. 15), the determination processing unit 51c corresponds to the situation of FIG. It is determined that there is an abnormality in the optical free space communication due to the intrusion of (step ST12 in FIG. 15). Signal strength S N is, as a situation where there is a time period following the signal strength 111, smaller than some of the time of the signal strength S N signal strength 111, and the signal strength 122 of the larger peak than the signal strength 111 It is possible that the situation is occurring.
　制御部５２は、判定部５１から出力された判定結果が、光空間通信が正常である旨を示していれば、光空間通信を有効にして、ＲＦ空間通信を無効にするため、光空間通信を実施する旨を示す制御信号を送信用スイッチ２１及び受信用スイッチ３２のそれぞれに出力する。 If the determination result output from the determination unit 51 indicates that the optical space communication is normal, the control unit 52 enables the optical space communication and disables the RF space communication. A control signal indicating that the above is performed is output to each of the transmission switch 21 and the reception switch 32.
　送信用スイッチ２１は、制御部５２から、光空間通信を実施する旨を示す制御信号を受けると、引き続き、送信用バッファ１１によりバッファリングされている送信用の通信データをデータ変調駆動回路２２に出力する。
　ただし、ＲＦ空間通信を有効にして、光空間通信を無効にしている状況下において、制御部５２から、光空間通信を実施する旨を示す制御信号を受けると、送信用スイッチ２１は、ＲＦ空間通信を無効にして、光空間通信を有効にするように、通信の切替を行う。
　具体的には、送信用スイッチ２１は、送信用バッファ１１によりバッファリングされている送信用の通信データをＲＦトランシーバ３の送信用バッファ４１に出力している状況から、送信用の通信データをデータ変調駆動回路２２に出力する状況に切り替える。 When the transmission switch 21 receives from the control unit 52 a control signal indicating that optical space communication is to be performed, the transmission switch 21 continuously transmits the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. Output.
However, when the RF space communication is enabled and the optical space communication is disabled, when the control signal indicating that the optical space communication is performed is received from the control unit 52, the transmission switch 21 causes the transmission switch 21 to operate in the RF space. The communication is switched so that the communication is disabled and the optical space communication is enabled.
Specifically, the transmission switch 21 outputs the communication data for transmission from the situation in which the communication data for transmission buffered by the transmission buffer 11 is being output to the transmission buffer 41 of the RF transceiver 3. The output is switched to the modulation drive circuit 22.
　受信用スイッチ３２は、制御部５２から、光空間通信を実施する旨を示す制御信号を受けると、引き続き、データ通信用光受信機３１から出力された通信データをデータインタフェース部１の受信用バッファ１２に出力する。
　ただし、ＲＦ空間通信を有効にして、光空間通信を無効にしている状況下において、制御部５２から、光空間通信を実施する旨を示す制御信号を受けると、受信用スイッチ３２は、ＲＦ空間通信を無効にして、光空間通信を有効にするように、通信の切替を行う。
　具体的には、受信用スイッチ３２は、受信用バッファ４４によりバッファリングされている通信データを受信用バッファ１２に出力している状況から、データ通信用光受信機３１から出力された通信データを受信用バッファ１２に出力する状況に切り替える。 When the receiving switch 32 receives the control signal indicating that the optical space communication is performed from the control unit 52, the receiving switch 32 continuously receives the communication data output from the data communication optical receiver 31 into the receiving buffer of the data interface unit 1. Output to 12.
However, when the RF space communication is enabled and the optical space communication is disabled, when the control signal indicating that the optical space communication is performed is received from the control unit 52, the reception switch 32 causes the reception space 32 to be in the RF space. The communication is switched so that the communication is disabled and the optical space communication is enabled.
Specifically, the reception switch 32 outputs the communication data output from the data communication optical receiver 31 from the situation in which the communication data buffered by the reception buffer 44 is being output to the reception buffer 12. The situation is switched to output to the reception buffer 12.
　制御部５２は、判定部５１から出力された判定結果が、光空間通信が異常である旨を示していれば、ＲＦ空間通信を有効にして、光空間通信を無効にするため、ＲＦ空間通信を実施する旨を示す制御信号を送信用スイッチ２１及び受信用スイッチ３２のそれぞれに出力する。 If the determination result output from the determination unit 51 indicates that the optical space communication is abnormal, the control unit 52 enables the RF space communication and disables the optical space communication. A control signal indicating that the above is performed is output to each of the transmission switch 21 and the reception switch 32.
　送信用スイッチ２１は、制御部５２から、ＲＦ空間通信を実施する旨を示す制御信号を受けると、送信用バッファ１１によりバッファリングされている送信用の通信データをＲＦトランシーバ３の送信用バッファ４１に出力する。
　受信用スイッチ３２は、制御部５２から、ＲＦ空間通信を実施する旨を示す制御信号を受けると、ＲＦトランシーバ３の受信用バッファ４４によりバッファリングされている通信データをデータインタフェース部１の受信用バッファ１２に出力する。 When the transmission switch 21 receives from the control unit 52 a control signal indicating that RF space communication is to be performed, the transmission switch 21 sends the transmission communication data buffered by the transmission buffer 11 to the transmission buffer 41 of the RF transceiver 3. Output to.
When receiving the control signal indicating that the RF space communication is to be performed, the receiving switch 32 receives the communication data buffered by the receiving buffer 44 of the RF transceiver 3 from the control unit 52 for receiving the data interface unit 1. Output to the buffer 12.
　以上の実施の形態１は、識別信号と通信データを含む光信号の光空間通信を行う光トランシーバ２と、通信データを含むＲＦ信号のＲＦ空間通信を行うＲＦトランシーバ３と、光トランシーバ２から光信号が送信されたのち、光トランシーバ２により受信された光信号の後方散乱光に含まれている識別信号における信号強度の時間変化に基づいて、光空間通信が正常であるか否かを判定し、光空間通信が異常であれば、信号強度の時間変化に基づいて、光空間通信の異常要因を判定する判定部５１とを備えるように、光空間通信装置を構成した。したがって、光空間通信装置は、光空間通信の異常要因を特定することができる。 In the first embodiment described above, the optical transceiver 2 for performing the optical space communication of the optical signal including the identification signal and the communication data, the RF transceiver 3 for performing the RF space communication of the RF signal including the communication data, and the optical transceiver 2 After the signal is transmitted, it is determined whether or not the optical space communication is normal based on the temporal change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver 2. If the optical space communication is abnormal, the optical space communication device is configured so as to include the determination unit 51 that determines the cause of the abnormality in the optical space communication based on the temporal change in the signal strength. Therefore, the optical space communication device can identify the cause of abnormality in the optical space communication.
　また、実施の形態１は、判定部５１により光空間通信が正常であると判定されれば、光空間通信を有効にして、ＲＦ空間通信を無効にし、判定部５１により光空間通信が異常であると判定されれば、ＲＦ空間通信を有効にして、光空間通信を無効にする制御部５２を備えるように、光空間通信装置を構成した。したがって、光空間通信装置は、光空間通信が異常である場合でも、通信データの伝送を継続することができる。 Further, in the first embodiment, if the determination unit 51 determines that the optical space communication is normal, the optical space communication is enabled, the RF space communication is disabled, and the determination unit 51 determines that the optical space communication is abnormal. If it is determined that the optical space communication device is configured, the optical space communication device is configured to include the control unit 52 that enables the RF space communication and disables the optical space communication. Therefore, the optical space communication device can continue the transmission of communication data even when the optical space communication is abnormal.
　さらに、実施の形態１は、望遠鏡３０により受信された光信号の波長が、通信相手の光空間通信装置から送信された光信号の波長であれば、当該光信号をデータ通信用光受信機３１に出力し、望遠鏡３０により受信された光信号の波長が、望遠鏡３０から送信された光信号の波長であれば、当該光信号を光サーキュレータ２８に出力する波長分岐カプラ２９を備えるように、光空間通信装置を構成した。したがって、光空間通信装置は、１つの望遠鏡３０が、通信相手の光空間通信装置から送信された光信号の受信と、望遠鏡３０から送信された光信号の後方散乱光の受信とを兼ねることができる。 Further, in the first embodiment, if the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner, the optical signal is transmitted to the optical receiver 31 for data communication. If the wavelength of the optical signal output by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, the optical signal is provided so as to include the wavelength branching coupler 29 that outputs the optical signal to the optical circulator 28. Configured the spatial communication device. Therefore, in the optical space communication device, one telescope 30 may serve both as the reception of the optical signal transmitted from the optical space communication device of the communication partner and the reception of the backscattered light of the optical signal transmitted from the telescope 30. it can.
　なお、本願発明はその発明の範囲内において、実施の形態の任意の構成要素の変形、もしくは実施の形態の任意の構成要素の省略が可能である。 It should be noted that the invention of the present application is capable of modifying any of the constituent elements of the embodiment or omitting any of the constituent elements of the embodiment within the scope of the invention.
　この発明は、光信号の光空間通信を行う光空間通信装置及び光空間通信方法に適している。 The present invention is suitable for an optical space communication device and an optical space communication method for performing optical space communication of optical signals.
　１　データインタフェース部、２　光トランシーバ、３　ＲＦトランシーバ、１１　送信用バッファ、１２　受信用バッファ、２１　送信用スイッチ、２２　データ変調駆動回路、２３　バースト変調駆動回路、２４　信号合波器、２５　基準光源、２６　光強度変調器、２７　蓄積型光増幅器、２８　光サーキュレータ、２９　波長分岐カプラ、３０　望遠鏡、３１　データ通信用光受信機、３２　受信用スイッチ、３３　光受信機、３４　時系列信号処理部、３５　モニタ用バッファ、４１　送信用バッファ、４２　送受信機、４３　送受信アンテナ、４４　受信用バッファ、５１　判定部、５１ａ　データ取得部、５１ｂ　信号強度比較部、５１ｃ　判定処理部、５２　制御部、６１　受信信号入力部、６２　トリガ信号入力部、６３　識別信号抽出部、６４　クロック発生部、６５　ＬＰＦ、６６　ＡＤＣ、６７　データバッファ、６８　データ抽出部、６９　信号強度算出部、７０　フーリエ変換部、７１　信号強度算出処理部、７２　時間変化データ生成部、７３　データ出力部、８１　データ抽出回路、８２　フーリエ変換回路、８３　信号強度算出処理回路、８４　時間変化データ生成回路、８５　データ取得回路、８６　信号強度比較回路、８７　判定処理回路、８８　制御回路、９１，９３　メモリ、９２，９４　プロセッサ、１０１，１０２　後方散乱光、１１１～１２３　信号強度、１１１ａ，１１３ａ，１１５ａ，１１７ａ，１１９ａ，１２１ａ　信号強度。 1 data interface unit, 2 optical transceiver, 3 RF transceiver, 11 transmission buffer, 12 reception buffer, 21 transmission switch, 22 data modulation drive circuit, 23 burst modulation drive circuit, 24 signal multiplexer, 25 reference light source, 26 optical intensity modulator, 27 storage type optical amplifier, 28 optical circulator, 29 wavelength branching coupler, 30 telescope, 31 data communication optical receiver, 32 receiving switch, 33 optical receiver, 34 time series signal processing unit, 35 Monitor buffer, 41 transmission buffer, 42 transceiver, 43 transmission / reception antenna, 44 reception buffer, 51 determination unit, 51a data acquisition unit, 51b signal strength comparison unit, 51c determination processing unit, 52 control unit, 61 reception signal input Section, 62 trigger signal input section, 63 identification signal extraction section, 64 clock generation section, 65 LPF, 66 ADC, 67 data buffer, 68 data extraction section, 69 signal strength calculation section, 70 Fourier transform section, 71 signal strength calculation processing Section, 72 time change data generation section, 73 data output section, 81 data extraction circuit, 82 Fourier transform circuit, 83 signal strength calculation processing circuit, 84 time change data generation circuit, 85 data acquisition circuit, 86 signal strength comparison circuit, 87 Judgment processing circuit, 88 control circuit, 91, 93 memory, 92, 94 processor, 101, 102 backscattered light, 111-123 signal strength, 111a, 113a, 115a, 117a, 119a, 121a signal strength.

Claims (6)

  1. 　識別信号と通信データを含む光信号の光空間通信を行う光トランシーバと、
    　前記通信データを含む無線周波数信号の無線周波数空間通信を行う無線周波数トランシーバと、
    　前記光トランシーバから光信号が送信されたのち、前記光トランシーバにより受信された前記光信号の後方散乱光に含まれている識別信号における信号強度の時間変化に基づいて、前記光空間通信が正常であるか否かを判定し、前記光空間通信が異常であれば、前記信号強度の時間変化に基づいて、前記光空間通信の異常要因を判定する判定部と
    　を備えた光空間通信装置。     An optical transceiver that performs optical space communication of an optical signal including an identification signal and communication data,
    A radio frequency transceiver for performing radio frequency spatial communication of a radio frequency signal including the communication data,
    After the optical signal is transmitted from the optical transceiver, the optical space communication is normally performed based on the time change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver. An optical space communication device comprising: a determination unit that determines whether or not the optical space communication is abnormal, and determines an abnormal factor of the optical space communication based on a temporal change in the signal strength.
  2. 　前記判定部により前記光空間通信が正常であると判定されれば、前記光空間通信を有効にして、前記無線周波数空間通信を無効にし、前記判定部により前記光空間通信が異常であると判定されれば、前記無線周波数空間通信を有効にして、前記光空間通信を無効にする制御部を備えたことを特徴とする請求項１記載の光空間通信装置。 If the determination unit determines that the optical space communication is normal, the optical space communication is enabled, the radio frequency spatial communication is disabled, and the determination unit determines that the optical space communication is abnormal. The optical space communication device according to claim 1, further comprising a control unit that enables the radio frequency space communication and disables the optical space communication.
  3. 　前記識別信号の周波数と、前記通信データの周波数帯域とが異なり、
    　前記光トランシーバは、
    　前記光信号の後方散乱光に含まれている通信データの通過を阻止して、前記後方散乱光に含まれている識別信号を抽出する識別信号抽出部と、
    　前記識別信号抽出部により抽出された識別信号の信号強度を算出する信号強度算出部と、
    　前記信号強度算出部により信号強度が算出される毎に、前記信号強度を保存することで、前記信号強度の時間変化を示す時間変化データを生成する時間変化データ生成部とを備え、
    　前記判定部は、
    　前記時間変化データ生成部により生成された時間変化データが示す時間変化に基づいて、前記光空間通信が正常であるか否かを判定し、前記光空間通信が異常であれば、前記時間変化データが示す時間変化に基づいて、前記光空間通信の異常要因を判定することを特徴とする請求項１記載の光空間通信装置。     The frequency of the identification signal and the frequency band of the communication data are different,
    The optical transceiver is
    An identification signal extraction unit that blocks passage of communication data included in the backscattered light of the optical signal and extracts an identification signal included in the backscattered light,
    A signal strength calculation unit that calculates the signal strength of the identification signal extracted by the identification signal extraction unit;
    Each time the signal strength is calculated by the signal strength calculation unit, the signal strength is stored, and a time change data generation unit that generates time change data indicating a time change of the signal strength is provided.
    The determination unit,
    Based on the time change indicated by the time change data generated by the time change data generation unit, it is determined whether the optical space communication is normal, and if the optical space communication is abnormal, the time change data. The optical space communication device according to claim 1, wherein an abnormal factor of the optical space communication is determined based on a temporal change indicated by.
  4. 　前記判定部は、前記時間変化データ生成部により生成された時間変化データが示す時間変化と、前記光空間通信が正常であるときの信号強度の時間変化とを比較することで、前記光空間通信が正常であるか否かの判定と、前記異常要因の判定とを行うことを特徴とする請求項３記載の光空間通信装置。 The determination unit compares the time change indicated by the time change data generated by the time change data generation unit with the time change of the signal strength when the optical space communication is normal, thereby performing the optical space communication. 4. The optical space communication device according to claim 3, wherein it is determined whether or not is normal, and the determination of the abnormal factor.
  5. 　前記光トランシーバから送信される光信号の波長と、通信相手の光空間通信装置から送信される光信号の波長とが異なり、
    　前記光トランシーバは、
    　光信号を送受信する望遠鏡と、
    　前記望遠鏡により受信された光信号の波長が、通信相手の光空間通信装置から送信された光信号の波長であれば、通信データを復調するためのデータ通信用光受信機に当該光信号を出力し、前記望遠鏡により受信された光信号の波長が、前記望遠鏡から送信された光信号の波長であれば、当該光信号を前記判定部に出力する波長分岐カプラとを備えていることを特徴とする請求項１記載の光空間通信装置。     The wavelength of the optical signal transmitted from the optical transceiver and the wavelength of the optical signal transmitted from the optical space communication device of the communication partner are different,
    The optical transceiver is
    A telescope that sends and receives optical signals,
    If the wavelength of the optical signal received by the telescope is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner, the optical signal is output to the optical receiver for data communication for demodulating communication data. However, if the wavelength of the optical signal received by the telescope is the wavelength of the optical signal transmitted from the telescope, a wavelength branching coupler that outputs the optical signal to the determination unit is provided. The optical space communication device according to claim 1.
  6. 　光トランシーバが、識別信号と通信データを含む光信号の光空間通信を行い、
    　無線周波数トランシーバが、前記通信データを含む無線周波数信号の無線周波数空間通信を行い、
    　判定部が、前記光トランシーバから光信号が送信されたのち、前記光トランシーバにより受信された前記光信号の後方散乱光に含まれている識別信号における信号強度の時間変化に基づいて、前記光空間通信が正常であるか否かを判定し、前記光空間通信が異常であれば、前記信号強度の時間変化に基づいて、前記光空間通信の異常要因を判定する
    　光空間通信方法。     An optical transceiver performs optical space communication of an optical signal including an identification signal and communication data,
    A radio frequency transceiver performs radio frequency spatial communication of a radio frequency signal containing the communication data,
    The determination unit, after the optical signal is transmitted from the optical transceiver, based on the temporal change of the signal intensity in the identification signal included in the backscattered light of the optical signal received by the optical transceiver, the optical space An optical space communication method for determining whether communication is normal, and if the optical space communication is abnormal, determining an abnormality factor of the optical space communication based on a temporal change of the signal strength.
PCT/JP2018/042999 2018-11-21 2018-11-21 Optical spatial communication device and optical spatial communication method WO2020105143A1 (en)

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JP2003520491A (en) * 2000-01-13 2003-07-02 ライトポイント コミュニケーションズ インコーポレイテッド Hybrid wireless optical and radio frequency communication links
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