CN109756321B - Time synchronization device and method - Google Patents
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Abstract
The embodiment of the invention discloses a time synchronization device, which comprises: a second receiver, a third receiver and a time delay device; the second receiver is used for receiving the first laser signal sent by the opposite-end time synchronization device and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite end time synchronizer; the third receiver is used for receiving the third laser signal and converting the third laser signal into a corresponding third time pulse signal; and the delayer is used for receiving the control signal sent by the opposite-end time synchronization device and carrying out time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal. The embodiment of the invention also discloses another time synchronization device and a time synchronization method corresponding to the time synchronization device.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a time synchronization apparatus and method.
Background
The high-precision time synchronization technology plays an extremely important role in modern scientific experiments and engineering applications, and aims to enable two or more reference time pulse signal sources which are separated from each other by a certain distance to be synchronized in phase and frequency. The high-precision time synchronization technology is widely applied to the fields of communication, radar detection, remote measuring technology, navigation system, astronomical observation, basic scientific research and the like.
In the existing time synchronization system, the adopted synchronization techniques are as follows: a common view synchronization technology based on a Global Positioning System (GPS), a time synchronization technology adopting satellite two-way time comparison, a time synchronization technology based on optical fiber frequency transmission, and a time synchronization technology based on laser two-way comparison transmission. However, the existing synchronization technology has the following problems: the GPS common-view synchronization technology and the satellite two-way time comparison synchronization technology are easily influenced by atmospheric turbulence, so that the synchronization precision is greatly limited; although the synchronization precision of the time synchronization technology based on optical fiber frequency transmission is high, a special optical fiber channel needs to be constructed in the transmission mode, and the synchronization technology cannot be used in the occasions where no existing optical fiber link exists or the optical fiber link is inconvenient to construct, so that the application of the optical fiber time synchronization technology is limited to a certain extent by the use condition.
Although the time synchronization technology based on the laser bidirectional comparison transmission has higher time synchronization precision and overcomes the limitation of an optical fiber link, the existing time synchronization system based on the time synchronization technology based on the laser bidirectional comparison transmission still has the following problems: two sets of lasers need to be configured in the system, the size of the lasers is large, and the portability and the flexibility of the synchronous system are not high.
Disclosure of Invention
In order to solve the above technical problems, embodiments of the present invention are directed to providing a time synchronization apparatus and method, which improve portability and flexibility of a time synchronization system.
The technical scheme of the invention is realized as follows: the embodiment of the invention provides a time synchronization method, which comprises the following steps:
a local time synchronization apparatus, the apparatus comprising: a time source, a transmitter, a first receiver, and a measurer;
a time source for generating a first time pulse signal; the transmitter is used for converting the first time pulse signal into a first laser signal and sending the first laser signal to an opposite end time synchronization device, so that the opposite end time synchronization device decomposes the first laser signal into a second laser signal; the first receiver is used for receiving the second laser signal reflected by the opposite-end time synchronization device and converting the second laser signal into a corresponding second time pulse signal; and the measurer is used for generating a control signal according to the time delay information between the first time pulse signal and the second time pulse signal, and sending the control signal to the opposite-end time synchronization device so that the opposite-end time synchronization device performs time synchronization adjustment operation according to the control signal.
The embodiment of the invention also provides another time synchronization device, which comprises: a second receiver, a third receiver and a time delay device; wherein,
the second receiver is used for receiving the first laser signal sent by the opposite-end time synchronization device and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite-end time synchronization device; the third receiver is used for receiving a third laser signal and converting the third laser signal into a corresponding third time pulse signal; and the delayer is used for receiving the control signal sent by the opposite-end time synchronization device and carrying out time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
The embodiment of the invention also provides a time synchronization method, which comprises the following steps:
generating a first time pulse signal; converting the first time pulse signal into a first laser signal, and sending the first laser signal to an opposite end time synchronization device, so that the opposite end time synchronization device decomposes the first laser signal into a second laser signal; receiving a second laser signal reflected by the opposite-end time synchronization device, and converting the second laser signal into a corresponding second time pulse signal; and generating a control signal according to the time delay information between the first time pulse signal and the second time pulse signal, and sending the control signal to the opposite-end time synchronization device, so that the opposite-end time synchronization device performs time synchronization adjustment operation according to the control signal.
The embodiment of the invention also provides another time synchronization method, which is characterized by comprising the following steps:
receiving a first laser signal sent by an opposite-end time synchronization device, and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite-end time synchronization device; receiving a third laser signal and converting the third laser signal into a corresponding third time pulse signal; and receiving a control signal sent by the opposite-end time synchronization device, and performing time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the steps of any one of the methods described above.
The embodiment of the invention provides a time synchronization device and a method, wherein the device comprises: a second receiver, a third receiver and a time delay device; the second receiver is used for receiving the first laser signal sent by the opposite-end time synchronization device and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite end time synchronizer; the third receiver is used for receiving the third laser signal and converting the third laser signal into a corresponding third time pulse signal; and the delayer is used for receiving the control signal sent by the opposite-end time synchronization device and carrying out time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
By adopting the time synchronization device, only the time source and the laser need to be configured in the time synchronization device at the time signal generation end, and the time source and the laser do not need to be configured in the time synchronization device at the time signal synchronization end, so that the structural complexity of the time synchronization device is reduced, and the portability and the flexibility of the time synchronization device are improved.
Drawings
FIG. 1 is a schematic diagram of a time synchronization system according to the prior art;
FIG. 2 is a schematic diagram illustrating a structure of a time synchronization apparatus according to a first embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating a structure of a time synchronization apparatus according to a second embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a structure of a first time synchronization system according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a delay unit according to a third embodiment of the present invention;
FIG. 6 is a schematic diagram illustrating a second exemplary time synchronization system according to an embodiment of the present invention;
FIG. 7 is a flowchart of a first embodiment of a method for time synchronization according to an embodiment of the present invention;
fig. 8 is a flowchart of a time synchronization method according to a second embodiment of the present invention.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
Fig. 1 is a schematic structural diagram of a time synchronization system in the prior art, and as shown in fig. 1, a time synchronization system 10 includes: a local end 11 and a remote end 12, wherein the local end 11 includes: a time source 111, a laser 112, a circulator 113, a beam expander 114, a photodetector 115 and a comparator 116; the distal end 12 includes: a time source 121, a laser 122, a circulator 123, a beam expander 124, a photodetector 125, and a comparator 126.
Here, the method for the remote end 12 to perform time synchronization according to the local time includes: the time source 111 generates a local time signal; the laser 112 converts the time signal into a corresponding local laser signal, and the local laser signal is transmitted to the far end 12 after passing through the circulator 113 and the beam expander 114; the beam expander 124 and the circulator 123 of the far end 12 receive the local laser signal, the photodetector 125 converts the local laser signal into a corresponding time signal, the comparator 126 compares the far end time signal generated by the time source 121 with the locally transmitted time signal to obtain a time difference between the far end time signal and the locally transmitted time signal, and the far end time is adjusted according to the time difference to achieve synchronization between the far end time and the local time.
The method for the local end 11 to perform time synchronization according to the remote time includes: the time source 121 generates a remote time signal; the laser 122 converts the time signal into a corresponding far-end laser signal, and the far-end laser signal is sent to the local end 11 after passing through the circulator 123 and the beam expander 124; the beam expander 114 and the circulator 113 of the local end 11 receive the far-end laser signal, the photodetector 115 converts the far-end laser signal into a corresponding time signal, the comparator 116 compares the local time signal generated by the time source 111 with the time signal sent by the far end to obtain a time difference between the local time signal and the time signal, and the local time is adjusted according to the time difference to achieve synchronization between the local time and the far end.
It can be seen that, in the prior art, when time synchronization is performed between different devices, both the local end and the remote end need to include a time source and a laser, the time synchronization device has a complicated structure, the flexibility and the portability of the device are low, and the time adjustment is performed by using an inherent delay line, the delay range of which does not exceed picoseconds, and the use range of the device is limited.
In order to solve the problems in the prior art, an embodiment of the present invention provides a time synchronization apparatus, fig. 2 is a schematic structural diagram of the time synchronization apparatus in the first embodiment of the present invention, and as shown in fig. 2, the time synchronization apparatus 20 includes: a time source 201, a transmitter 202, a first receiver 203 and a measurer 204; wherein,
a time source 201 for generating a first time pulse signal;
the transmitter 202 is configured to convert the first time pulse signal into a first laser signal, and send the first laser signal to the opposite-end time synchronization device, so that the opposite-end time synchronization device decomposes the first laser signal into a second laser signal;
the first receiver 203 is configured to receive a second laser signal reflected by the peer-to-peer time synchronization device, and convert the second laser signal into a corresponding second time pulse signal;
the measurer 204 is configured to generate a control signal according to the time delay information between the first time pulse signal and the second time pulse signal, and send the control signal to the opposite-end time synchronization device, so that the opposite-end time synchronization device performs time synchronization adjustment operation according to the control signal.
In the first embodiment of the present invention, the time synchronizer is a local time synchronizer, and the peer time synchronizer is a remote time synchronizer.
Illustratively, the remote time synchronization device is specifically configured to receive a first laser signal sent by the local time synchronization device, and decompose the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the local time synchronizer; and the laser processing device is also used for receiving a third laser signal and converting the third laser signal into a corresponding third time pulse signal.
Illustratively, the remote time synchronizer is further configured to obtain a time pulse signal synchronized with the first time pulse signal according to the third time pulse signal after receiving the control signal sent by the measurer 204.
In practical implementation, the time source may be a crystal oscillator for generating a stable first time pulse signal, such as: a quartz crystal oscillator.
In an optional implementation manner, the delay information is free delay; the free time delay is the transmission time of the laser signal transmitted from the time synchronizer to the opposite end time synchronizer.
Here, when the signal processing delay introduced by the local time synchronizer when converting the received second laser signal into the second time pulse signal is different from the signal processing delay introduced by the remote time synchronizer when converting the received third laser signal into the third time pulse signal, the measurer may send the calculated free delay to the remote time synchronizer only, and the remote time synchronizer calculates the sum of the free delay and the fixed delay introduced by the remote time synchronizer to obtain the total delay time, and then performs a time synchronization adjustment operation on the obtained time pulse signal according to the total delay time to obtain the synchronization time signal.
In another optional implementation, the delay information is a sum of a free delay and a first fixed delay; the free time delay is transmission time of the laser signal transmitted from the time synchronizer to the opposite end time synchronizer, and the first fixed time delay is signal processing time delay introduced into the time synchronizer.
Specifically, the first fixed time delay is a first signal processing time delay introduced after the local time synchronization device converts the generated first time pulse signal into the first laser signal, and is added with a second signal processing time delay introduced when the received second laser signal is converted into the second time pulse signal, so that all signal processing time delays introduced inside the local time synchronization device are obtained.
Here, when the signal processing delay introduced by the local time synchronization device when converting the received second laser signal into the second time pulse signal is the same as the signal processing delay introduced by the remote time synchronization device when converting the received third laser signal into the third time pulse signal, the measurer may also send the sum of the free delay and the first fixed delay to the remote time synchronization device, and the remote time synchronization device directly performs a time synchronization adjustment operation on the obtained time pulse signal according to the received delay information to obtain the synchronized time signal.
In practical implementation, the transmitter may include: an encoder and a laser; the encoder is used for encoding the first time pulse signal to obtain a first time encoding sequence; and the laser is used for loading the first time code sequence to generate a first laser signal.
Illustratively, the transmitter may further include: a first beam expander; the first speed expanding lens is mainly used for expanding the diameter of the laser beam and reducing the divergence angle of the laser beam, is used for coupling the laser signal to a free space, and is plated with an antireflection film at the position of the objective lens according to different wavelengths.
For example, the measuring Device and the encoder may be formed by at least one of an Application Specific Integrated Circuit (ASIC), a Digital Signal Processing (DSP), a Complex Programmable Logic Device (CPLD), a Field Programmable Gate Array (FPGA), and the like, and the encodable code pattern may be: serial time code (InterRange Instrumentation Group, IRIG-B).
The laser can be a small continuous laser, and can generate a single-frequency continuous laser with adjustable wavelength, so that the generated laser signal has high monochromaticity and side-to-die suppression ratio, such as: a continuous solid laser with adjustable wavelength. The small continuous laser can reduce the space occupation of the local time synchronization device and improve the portability and the flexibility of the device.
In practical implementation, the first receiver may include: a first photodetector and a first decoder; the first photoelectric detector is used for receiving a second laser signal and converting the second laser signal into a second coding sequence; and the first decoder is used for decoding the second coding sequence to obtain a second time pulse signal.
Illustratively, the first receiver may further include: a second beam expander; the second beam expander is used for receiving the second laser signal and transmitting the received second laser signal to the first power-off detector.
Second embodiment
In order to solve the problems in the prior art, an embodiment of the present invention provides a time synchronization apparatus, fig. 3 is a schematic structural diagram of a time synchronization apparatus in a second embodiment of the present invention, and as shown in fig. 3, a time synchronization apparatus 30 includes: a second receiver 301, a third receiver 302 and a time delay 303; wherein,
the second receiver 301 is configured to receive a first laser signal sent by the peer-to-peer time synchronization device, and decompose the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite end time synchronizer;
a third receiver 302, configured to receive a third laser signal and convert the third laser signal into a corresponding third time pulse signal;
and the delayer 303 is configured to receive the control signal sent by the peer time synchronization device, and perform time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
In the second embodiment of the present invention, the time synchronizer is a remote time synchronizer, and the peer time synchronizer is a local time synchronizer.
In practical implementation, the time delay 303 is specifically configured to receive a control signal sent by the local time synchronization device, and adjust the third time pulse signal according to the control signal to obtain a time pulse signal synchronized with the first time pulse signal; the first time pulse signal is generated by a local time synchronization device, and the first laser signal is obtained by converting the first time pulse signal by the local time synchronization device.
In an optional implementation manner, the delay information is free delay; the free time delay is the transmission time of the laser signal when the laser signal is transmitted from the local time synchronizer to the remote time synchronizer. The time delayer is specifically used for adjusting the third time pulse signal according to the sum of the free time delay and a second fixed time delay, wherein the second fixed time delay is the sum of the first processing time delay and the public fixed time delay; the first processing time delay is a signal processing time delay introduced when the time synchronization device converts the third laser signal into a third time pulse signal; the common fixed time delay is a signal processing time delay introduced when the opposite-end time synchronization device converts the generated first time pulse signal into the first laser signal.
Here, when the signal processing delay introduced by the local time synchronizer when converting the received second laser signal into the second time pulse signal is different from the signal processing delay introduced by the remote time synchronizer when converting the received third laser signal into the third time pulse signal, the measurer may send the calculated free delay to the remote time synchronizer only, and the remote time synchronizer calculates the sum of the free delay and the fixed delay introduced by the remote time synchronizer to obtain the total delay time, and then performs a time synchronization adjustment operation on the obtained time pulse signal according to the total delay time to obtain the synchronization time signal. Namely, the delayer adjusts the third time pulse signal according to the total delay time to obtain the time pulse signal synchronous with the first time pulse signal, thereby realizing the time synchronization between the far end and the local.
In another optional implementation, the delay information is a sum of a free delay and a first fixed delay; the free time delay is transmission time of the laser signal transmitted from the time synchronizer to the opposite end time synchronizer, and the first fixed time delay is signal processing time delay introduced into the time synchronizer.
Specifically, the first fixed time delay is a first signal processing time delay introduced after the local time synchronization device converts the generated first time pulse signal into the first laser signal, and is added with a second signal processing time delay introduced when the received second laser signal is converted into the second time pulse signal, so that all signal processing time delays introduced inside the local time synchronization device are obtained.
Here, when the signal processing delay introduced by the local time synchronization device when converting the received second laser signal into the second time pulse signal is the same as the signal processing delay introduced by the remote time synchronization device when converting the received third laser signal into the third time pulse signal, the measurer may also send the sum of the free delay and the first fixed delay to the remote time synchronization device, and the remote time synchronization device directly performs a time synchronization adjustment operation on the obtained time pulse signal according to the received delay information to obtain the synchronized time signal. I.e. the delayer adjusts the third time pulse signal directly according to the received delay information.
It can be seen that, in the embodiment of the present invention, the remote time synchronization apparatus can achieve time synchronization with the local time synchronization apparatus without configuring a time source and a laser, thereby reducing the complexity of the time synchronization apparatus and improving the portability of the time synchronization apparatus.
In practical implementation, the delay unit may perform any delay on the input time pulse signal, and the delay unit may be formed by at least one of an ASIC, a DSP, a CPLD, an FPGA, and the like. Illustratively, the delay device is an FPGA; the FPGA includes: the device comprises an input interface, an output interface and N shift registers, wherein N is a positive integer.
The input interface is used for sampling the third time pulse signal according to the sampling frequency, continuously acquiring N groups of sampling data, and respectively sending the acquired N groups of sampling data to the 1 st shift register and the Nth shift register;
each shift register is used for adjusting the received sampling data according to the control signal and sending the adjusted sampling data to the output interface;
and the output interface is used for sequentially outputting the sampling data adjusted by the 1 st shift register to the sampling data adjusted by the Nth shift register to obtain a synchronous time signal.
Here, an FPGA chip may be used to perform the time delay adjustment, so as to improve the sampling precision by setting N shift registers, and improve the adjustment range of the delay time by setting the depth of each shift register.
Illustratively, the second receiver may include: a beam splitter; and decomposing the first laser signal into a second laser signal and a third laser signal through a beam splitter, and sending the second laser signal to a local time synchronization device.
Optionally, the second receiver may further include: at least one mirror; the second laser signal is reflected to the local time synchronizer by the mirror.
The receiver comprises a combination of a beam splitter and a reflector, and is mainly used for dividing laser into two beams of transmission and reflection light with a certain light intensity ratio, and returning the reflection light to the transmitting end, wherein the reflection light is a second laser signal, and the transmission light is a third laser signal.
In the embodiment of the present invention, the local time synchronization apparatus includes: a time source, a transmitter, a first receiver, and a measurer; a time source for generating a first time pulse signal; the transmitter is used for converting the first time pulse signal into a first laser signal and sending the first laser signal to the opposite end time synchronization device, so that the opposite end time synchronization device decomposes the first laser signal into a second laser signal; the first receiver is used for receiving a second laser signal reflected by the opposite-end time synchronization device and converting the second laser signal into a corresponding second time pulse signal; and the measurer is used for generating a control signal according to the time delay information between the first time pulse signal and the second time pulse signal, and sending the control signal to the opposite-end time synchronization device so that the opposite-end time synchronization device performs time synchronization adjustment operation according to the control signal.
A remote time synchronization device, comprising: a second receiver, a third receiver and a time delay device; the second receiver is used for receiving the first laser signal sent by the opposite-end time synchronization device and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite end time synchronizer; the third receiver is used for receiving the third laser signal and converting the third laser signal into a corresponding third time pulse signal; and the delayer is used for receiving the control signal sent by the opposite-end time synchronization device and carrying out time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
By adopting the time synchronization device, only the time source and the laser need to be configured in the time synchronization device (namely, the local time synchronization device) of the time signal generation end, and the time source and the laser do not need to be configured in the time synchronization device (namely, the far-end time synchronization device) of the time signal synchronization end, so that the structural complexity of the time synchronization device is reduced, and the portability and the flexibility of the time synchronization device are improved.
Third embodiment
In order to further embody the object of the present invention, the following description is further exemplified on the basis of the first embodiment and the second embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a first time synchronization system according to an embodiment of the present invention, and as shown in fig. 4, the system includes: a local time synchronizer 41 and a remote time synchronizer 42; the embodiment of the invention introduces a time synchronization process between two stations, wherein the two stations comprise a local end and a remote end. Wherein,
the local time synchronizer 41 includes: a time source 411, an encoder 412, a laser 413, a first expander mirror 414, a second expander mirror 415, a first photodetector 416, a first decoder 417, and a measurer 418.
The remote time synchronizing device 42 includes: a mirror 421, a beam splitter 422, a third beam expander 423, a second photodetector 424, a second decoder 425, and a time delay 426.
In practical implementation, the time synchronization system is implemented as follows:
1. the local time source 411 generates a first time pulse signal with an initial time t0；
2. The first time pulse signal is coded by the coder 412 to obtain a first time coding sequence;
3. loading the first time code sequence onto the laser 413 in a current modulation or external modulation manner to obtain a first laser signal, and assuming that a common fixed time delay t is generated after passing through the laser 4131The time before the first laser signal is emitted can be recorded as t0+t1. Here, the laser may use a continuous laser with a wavelength of 1.5 μm as a local light source;
4. the first beam expander 414 couples the first laser signal into free space and passes through free space to the remote time synchronizer 42, assuming that there is a free time delay t in the free space unidirectional optical pathpThen the time when the first laser signal reaches the far end can be recorded as t0+t1+tpThe length of the time delay generated in the free space is related to the distance between the remote end and the local end;
5. after the far-end beam splitter 422 receives the first laser signal, the first laser signal is decomposed into two paths of laser signals, including a second laser signal and a third laser signal; the second laser signal is reflected back to the local time synchronizer 41 via the mirror 421; the third laser signal is received by the second photodetector 424 after passing through the remote third beam expander 423;
6. the second laser signal is received by the first photodetector 416 after passing through the second beam expander 415 at the local end, and the same free time delay t exists in the free space one-way optical path when the second laser signal is reflected from the far end back to the local endpTherefore, the time of the second laser signal transmitted from the remote end back to the local end can be recorded as t0+t1+2tp；
7. After the second laser signal at the local end is converted into an encoded signal by the first photodetector 416, the encoded signal is processed by the first decoder 417The decoding results in a second time pulse signal, assuming that the process results in a fixed time delay t by the first photodetector 416 and the first decoder 417c1If the time of the second time pulse signal after the local decoding is t0+t1+tc1+2tp(ii) a Wherein (t)1+tc1) Namely, the first fixed time delay in the embodiment of the present invention;
8. the third laser signal is received by the second photodetector 424 after passing through the remote third beam expander 423, the third laser signal is converted into a coded signal by the second photodetector 424, and then decoded by the second decoder 425 to obtain a third time pulse signal, and it is assumed that the fixed time delay t is also generated by the second photodetector 424 and the second decoder 425 in the processc2And the time of the third time pulse signal after the far-end decoding is recorded as t0+t1+tc2+tp(ii) a Wherein, tc2The time delay is the second fixed time delay in the embodiment of the present invention, that is, the signal processing time delay introduced inside the remote time synchronization device;
9. the first time pulse signal and the second time pulse signal are sent to the measuring device 418, and the time difference between the two signals is measured, and the time difference between the two signals is t1+tc1+2tpDue to (t)1+tc1) The first fixed time delay introduced into the local time synchronizer is obtained in advance, so that the time delay can be calibrated in advance to obtain t1And tc1Then the time delay t caused by the free space one-way optical path can be further calculatedp(ii) a Calculating the free time delay tpWith a first fixed time delay (t)1+tc1) Summing to generate a control signal; then sending the control signal to the remote end; here, tc1And tc2Equal; when t isc1And tc2When not equal, only free delay t is setpAnd sending the data to the remote end.
10. The remote delay 426 receives the third time pulse signal and the control signal and determines the delay time information t contained in the control signal1+tc1+tpImplementing a time delay to the third time pulse signalCompensation, tc1＝tc2I.e. t0+t1+tc2+tp-(t1+tc2+tp)＝t0The time delay compensation algorithm adjusts the time delay of the far-end delayer to offset the time delay t generated in the free space transmission so as to achieve the aim of synchronizing the far-end time signal and the local-end reference time pulse signalpAnd fixed time delay t generated in photoelectric detection coding and decoding1+tc1The time pulse signal of the far end and the time reference pulse signal of the local end are completely synchronized, so that the high-precision free space wireless time synchronization is realized.
In actual implementation, an FPGA delayer with an adjustment precision of nanoseconds and an adjustment range of milliseconds is designed for the requirement of the delayer 426 for performing large-range and high-precision delay adjustment on the third time pulse signal. Fig. 5 is a schematic diagram of a composition structure of a delay unit according to a third embodiment of the present invention, and as shown in fig. 5, the FPGA delay unit 50 at least includes: a sampling clock PLL501(Phase Locked Loop, chinese name: Phase Locked Loop), a logic control unit 502, an input interface 503, a shift register group 504, and an output interface 505, where the shift register group 504 includes: and 4 shift registers, namely a shift register 1, a shift register 2, a shift register 3 and a shift register 4.
The sampling clock PLL501 can output a stable and high-frequency sampling clock to control the normal operation of the input interface 503 and the output interface 505, and the control signal passes through the logic control unit 502 to control the shift register set 504 to perform the delay adjustment operation of the third time pulse signal.
Illustratively, the sampling clocks for the input interface 503 and the output interface 505 are both 250 MHz. Therefore, the sampling clock of each shift register channel is 250MHz, and the 1GHz equivalent sampling, namely the nanosecond precision time delay, can be finally realized through the precise combination control of the four shift registers. Meanwhile, a shift register with a certain depth can be set according to the register scales of different FPGAs, so that the millisecond-level time delay range is achieved.
In the embodiment of the invention, the photoelectric detector can convert the detected laser signal into the coded signal, the frequency response range of the coded signal can be from direct current to more than 1GHz, and the gain is adjustable.
In the embodiment of the present invention, the measurement of the round trip delay in the free space by the measurer 418 and the high-precision delay adjustment of the remote third time pulse signal by the delayer 426 enable the remote time synchronization device to implement the time synchronization with nanosecond precision and the millisecond-scale delay range adjustment between two stations.
Here, experimental verification is also performed on the time synchronization apparatus provided in the embodiment of the present invention, and taking as an example that a local-end time source generates a 10ms (100Hz) first time pulse signal to achieve time synchronization with a remote end, a time synchronization experiment is performed in an outdoor free space with a transmission distance between the local end and the remote end exceeding 100 m. In the synchronization process, time delay fluctuation and time instability of a time synchronization system between two stations are measured, a first time pulse signal of 10ms is transmitted within 5000s, the root mean square value of the measured time delay fluctuation is about 1ns, the time instability of a far end within 1s is 1 x 10^ (-10), and the time instability of the far end within kiloseconds is 1 x 10^ (-12). The time synchronization precision is better than that of the commercial GPS system, so the time synchronization system can replace the existing GPS-based time synchronization device under the distance of hundred meters.
Fourth embodiment
In order to further embody the object of the present invention, the following description is further exemplified on the basis of the first embodiment and the second embodiment of the present invention.
Fig. 6 is a schematic structural diagram of a second time synchronization system according to an embodiment of the present invention, and as shown in fig. 6, the system includes: a local time synchronizer 61, a remote 1 time synchronizer 62, and a remote 2 time synchronizer 63; the embodiment of the invention introduces a time synchronization process among three stations, wherein the three stations comprise a local end and 2 remote ends. Wherein,
the local time synchronizer 61 includes: the device comprises a time source, an encoder, a laser 1, a beam expander 2, a detection and decoder 1, a measurer 1, a laser 2, a beam expander 3, a beam expander 4, a detection and decoder 2 and a measurer 2. The system comprises a laser 1, a beam expander 2, a detection and decoder 1 and a measurer 1, wherein the laser 1, the beam expander, the detection and decoder 1 and the measurer 1 are used for completing the time synchronization process of a far end 1; the laser 2, the beam expander 3, the beam expander 4, the detection and decoder 2 and the measurer 2 are used for completing the time synchronization process of the far end 2.
The remote 1 time synchronizer 62 includes: beam splitter 621, mirror 622, beam expander 5, detector and decoder 3 and delay 1.
The remote 2 time synchronizer 63 includes: beam splitter 631, mirror 632, beam expander 6, detector and decoder 4 and delay 2.
Here, each remote end is configured with a corresponding receiving and transmitting device at the local end to achieve time synchronization for different remote ends. The detectors and decoders 1 to 4 are used to implement the functions of the photodetector and decoder in the third embodiment, and convert the received laser signal into a corresponding time pulse signal.
In actual implementation, the time synchronization operation between the local time synchronization device and the remote 1 time synchronization device or the remote 2 time synchronization device is the same as the implementation process of the local and remote devices in the third embodiment of the present invention, and is not described herein again.
In practical implementation, the plurality of measurers, the plurality of detectors and decoders, the plurality of beam expanders, and the plurality of time delays used by the time synchronization device may be the same or different, and these may be selected according to practical requirements, and the present invention is not limited specifically.
In the embodiment of the invention, when the time synchronization among the stations is realized, the local end can be provided with one laser, and the time synchronization of the remote time synchronization devices is realized by controlling one laser to respectively send laser signals to the remote time synchronization devices.
It should be noted that, the embodiment of the present invention only exemplarily provides a synchronization process among multiple stations, and an implementation method including more than 2 remote time synchronization apparatuses in actual implementation is the same as the implementation principle described above, and is not described herein again.
Fifth embodiment
Based on the same inventive concept, an embodiment of the present invention further provides a time synchronization method corresponding to the local time synchronization apparatus, fig. 7 is a flowchart of a first embodiment of the time synchronization method in the embodiment of the present invention, and as shown in fig. 7, the method includes:
step 701: a first time pulse signal is generated.
Step 702: and converting the first time pulse signal into a first laser signal, and sending the first laser signal to an opposite-end time synchronization device, so that the opposite-end time synchronization device decomposes the first laser signal into a second laser signal.
Here, the purpose of sending the first laser signal to the peer time synchronizer is to: and enabling the opposite-end time synchronization device to decompose the first laser signal into a second laser signal and a third laser signal. And reflecting the second laser signal; and converting the third laser signal into a corresponding third time pulse signal.
In a fifth embodiment of the present invention, the peer time synchronizer is a remote time synchronizer.
Step 703: and receiving a second laser signal reflected by the opposite-end time synchronization device, and converting the second laser signal into a corresponding second time pulse signal.
Step 704: and generating a control signal according to the time delay information between the first time pulse signal and the second time pulse signal, and sending the control signal to the opposite-end time synchronization device to enable the opposite-end time synchronization device to perform time synchronization adjustment operation according to the control signal.
Specifically, the purpose of sending the control signal to the remote time synchronization device is: and the far-end time synchronization device adjusts the third time pulse signal according to the control signal to obtain a time pulse signal synchronized with the first time pulse signal.
In an optional implementation manner, the delay information is free delay; the free time delay is the transmission time when the laser signal is transmitted to the opposite end time synchronizer.
In another optional implementation, the delay information is a sum of a free delay and a first fixed delay; the free time delay is transmission time of the laser signal transmitted from the time synchronizer to the opposite end time synchronizer, and the first fixed time delay is signal processing time delay introduced into the time synchronizer.
Optionally, it may also be monitored whether the remote time synchronization apparatus completes the time synchronization operation, that is, whether the received time pulse signal is successfully subjected to the time delay compensation, and if so, the time synchronization operation is ended; if not, the time synchronization operation is carried out again, such as: and reproducing and acquiring time delay information between the first time pulse signal and the second time pulse signal, generating a control signal, and performing time delay compensation according to the control signal so as to realize high-precision time synchronization.
Sixth embodiment
Based on the same inventive concept, an embodiment of the present invention further provides a time synchronization method corresponding to the remote time synchronization apparatus, fig. 8 is a flowchart of a second embodiment of the time synchronization method in the embodiment of the present invention, and as shown in fig. 8, the method includes:
step 801: receiving a first laser signal sent by an opposite-end time synchronization device, and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflects the second laser signal back to the opposite end time synchronizer.
In the sixth embodiment of the present invention, the peer time synchronizer is the local time synchronizer.
The local time synchronization device is specifically used for generating a first time pulse signal, converting the first time pulse signal into a first laser signal and sending the first laser signal; converting the received second laser signal into a corresponding second time pulse signal; and generating a control signal according to the time delay information between the first time pulse signal and the second time pulse signal.
Step 802: and receiving a third laser signal and converting the third laser signal into a corresponding third time pulse signal.
Step 803: and receiving a control signal sent by the opposite-end time synchronization device, and performing time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
In an optional implementation manner, the delay information is free delay; the free time delay is the transmission time from the time of sending the laser signal from the opposite end time synchronizer to the time of receiving the laser signal. Adjusting a third time pulse signal according to the sum of the free time delay and a second fixed time delay, wherein the second fixed time delay is the sum of a first processing time delay and a public fixed time delay, and the first processing time delay is a signal processing time delay introduced when a third laser signal is converted into the third time pulse signal; the common fixed time delay is a signal processing time delay introduced when the opposite-end time synchronization device converts the generated first time pulse signal into the first laser signal.
In another optional implementation, the delay information is a sum of a free delay and a first fixed delay; the free time delay is transmission time of the laser signal transmitted from the time synchronizer to the opposite end time synchronizer, and the first fixed time delay is signal processing time delay introduced into the time synchronizer.
In actual implementation, the FPGA is controlled to perform time synchronization adjustment on the third time pulse signal according to the control signal; the FPGA includes: the device comprises an input interface, an output interface and N shift registers, wherein N is a positive integer;
the input interface is used for sampling the third time pulse signal according to the sampling frequency, continuously acquiring N groups of sampling data, and respectively sending the acquired N groups of sampling data to the 1 st shift register and the Nth shift register;
each shift register is used for adjusting the received sampling data according to the control signal and sending the adjusted sampling data to the output interface;
and the output interface is used for sequentially outputting the sampling data adjusted by the 1 st shift register to the sampling data adjusted by the Nth shift register to obtain a synchronous time signal.
In practical implementation, a first laser signal sent by an opposite-end time synchronization device is received through a beam splitter, and the first laser signal is decomposed into a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite-end time synchronization device through the reflecting mirror.
Seventh embodiment
Based on the same inventive concept of the time synchronization method in the fifth embodiment, an embodiment of the present invention further provides a computer-readable storage medium, such as a memory including a computer program, which is executable by a processor of the time synchronization apparatus to perform the method steps in the foregoing fifth embodiment.
Eighth embodiment
Based on the same inventive concept of the time synchronization method in the sixth embodiment, an embodiment of the present invention further provides another computer-readable storage medium, such as a memory including a computer program, which is executable by a processor of the time synchronization apparatus to perform the method steps in the sixth embodiment.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.
The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks and/or flowchart block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks and/or flowchart block or blocks.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.
Claims (20)
1. A time synchronization apparatus for performing wireless time synchronization, the apparatus comprising: a time source, a transmitter, a first receiver, and a measurer;
a time source for generating a first time pulse signal;
the transmitter is used for converting the first time pulse signal into a first laser signal and sending the first laser signal to an opposite end time synchronization device, so that the opposite end time synchronization device decomposes the first laser signal into a second laser signal;
the first receiver is used for receiving the second laser signal reflected by the opposite-end time synchronization device and converting the second laser signal into a corresponding second time pulse signal;
and the measurer is used for generating a control signal according to the time delay information between the first time pulse signal and the second time pulse signal, and sending the control signal to the opposite-end time synchronization device so that the opposite-end time synchronization device performs time synchronization adjustment operation according to the control signal.
2. The apparatus of claim 1, wherein the latency information is free latency; the free time delay is the transmission time of the laser signal transmitted from the time synchronizer to the opposite end time synchronizer.
3. The apparatus of claim 1, wherein the delay information is a sum of a free delay and a first fixed delay; the free time delay is transmission time of a laser signal transmitted from the time synchronizer to the opposite end time synchronizer, and the first fixed time delay is signal processing time delay introduced into the time synchronizer.
4. The apparatus of claim 1, wherein the transmitter comprises: an encoder and a laser;
the encoder is used for encoding the first time pulse signal to obtain a first time encoding sequence;
the laser is used for loading the first time code sequence to generate the first laser signal.
5. The apparatus of claim 1, wherein the first receiver comprises: a first photodetector and a first decoder;
the first photoelectric detector is used for receiving the second laser signal and converting the second laser signal into a second coding sequence;
and the first decoder is used for decoding the second coding sequence to obtain the second time pulse signal.
6. A time synchronization apparatus for performing wireless time synchronization, the apparatus comprising: a second receiver, a third receiver and a time delay device; wherein,
the second receiver is used for receiving the first laser signal sent by the opposite-end time synchronization device and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite-end time synchronization device;
the third receiver is used for receiving a third laser signal and converting the third laser signal into a corresponding third time pulse signal;
and the delayer is used for receiving the control signal sent by the opposite-end time synchronization device and carrying out time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
7. The apparatus of claim 6, wherein the control signal comprises delay information, and wherein the delay information is free delay; the free time delay is the transmission time of the laser signal transmitted from the opposite end time synchronizer to the time synchronizer.
8. The apparatus according to claim 7, wherein the delay unit is specifically configured to adjust the third time pulse signal according to a sum of the free delay and a second fixed delay, where the second fixed delay is a sum of a first processing delay and a common fixed delay; the first processing time delay is a signal processing time delay introduced when the time synchronization device converts the third laser signal into a third time pulse signal; the common fixed time delay is a signal processing time delay introduced when the opposite-end time synchronization device converts the generated first time pulse signal into the first laser signal.
9. The apparatus of claim 6, wherein the delay timer is a Field Programmable Gate Array (FPGA); the FPGA comprises: the device comprises an input interface, an output interface and N shift registers, wherein N is a positive integer;
the input interface is used for sampling the third time pulse signal according to the sampling frequency, continuously acquiring N groups of sampling data, and respectively sending the acquired N groups of sampling data to the 1 st shift register and the Nth shift register;
each shift register is used for adjusting the received sampling data according to the control signal and sending the adjusted sampling data to the output interface;
and the output interface is used for sequentially outputting the sampling data adjusted by the 1 st shift register to the sampling data adjusted by the Nth shift register to obtain a synchronous time signal.
10. The apparatus of claim 6, wherein the second receiver comprises: a beam splitter and a mirror;
a beam splitter for splitting the first laser signal into a second laser signal and a third laser signal;
and the reflector is used for reflecting the second laser signal to the opposite end time synchronization device.
11. The apparatus of claim 6, wherein the third receiver comprises: a second photodetector and a second decoder;
the second photoelectric detector is used for receiving the third laser signal and converting the third laser signal into a third coding sequence;
and the second decoder is used for decoding the third coding sequence to obtain the third time pulse signal.
12. A method for time synchronization, which is used for implementing wireless time synchronization, and is characterized in that the method comprises:
generating a first time pulse signal;
converting the first time pulse signal into a first laser signal, and sending the first laser signal to an opposite end time synchronization device, so that the opposite end time synchronization device decomposes the first laser signal into a second laser signal;
receiving a second laser signal reflected by the opposite-end time synchronization device, and converting the second laser signal into a corresponding second time pulse signal;
and generating a control signal according to the time delay information between the first time pulse signal and the second time pulse signal, and sending the control signal to the opposite-end time synchronization device, so that the opposite-end time synchronization device performs time synchronization adjustment operation according to the control signal.
13. The method of claim 12, wherein the delay information is a free delay; the free time delay is the transmission time when the laser signal is transmitted to the opposite end time synchronizer.
14. A method for time synchronization, which is used for implementing wireless time synchronization, and is characterized in that the method comprises:
receiving a first laser signal sent by an opposite-end time synchronization device, and decomposing the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite-end time synchronization device;
receiving a third laser signal and converting the third laser signal into a corresponding third time pulse signal;
and receiving a control signal sent by the opposite-end time synchronization device, and performing time synchronization adjustment on the third time pulse signal according to the control signal to obtain a synchronization time signal.
15. The method of claim 14, wherein the control signal comprises delay information, and wherein the delay information is a free delay; the free time delay is the transmission time from the time of sending the laser signal to the time of receiving the laser signal from the opposite end time synchronizer.
16. The method of claim 15, wherein the time-synchronized adjusting of the third time pulse signal according to the control signal comprises: adjusting the third time pulse signal according to the sum of the free time delay and a second fixed time delay, wherein the second fixed time delay is the sum of a first processing time delay and a public fixed time delay, and the first processing time delay is a signal processing time delay introduced when the third laser signal is converted into the third time pulse signal; the common fixed time delay is a signal processing time delay introduced when the opposite-end time synchronization device converts the generated first time pulse signal into the first laser signal.
17. The method of claim 16, wherein the time-synchronized adjusting of the third time pulse signal according to the control signal comprises: controlling the FPGA to perform time synchronization adjustment on the third time pulse signal according to the control signal;
the FPGA comprises: the device comprises an input interface, an output interface and N shift registers, wherein N is a positive integer;
the input interface is used for sampling the third time pulse signal according to the sampling frequency, continuously acquiring N groups of sampling data, and respectively sending the acquired N groups of sampling data to the 1 st shift register and the Nth shift register;
each shift register is used for adjusting the received sampling data according to the control signal and sending the adjusted sampling data to the output interface;
and the output interface is used for sequentially outputting the sampling data adjusted by the 1 st shift register to the sampling data adjusted by the Nth shift register to obtain a synchronous time signal.
18. The method according to claim 14, wherein the receiving device receives a first laser signal sent by an opposite-end time synchronization device, and decomposes the first laser signal to obtain a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite end time synchronizer, comprising:
receiving a first laser signal sent by an opposite-end time synchronization device through a beam splitter, and decomposing the first laser signal into a second laser signal and a third laser signal; and reflecting the second laser signal back to the opposite-end time synchronization device through a reflector.
19. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method of any one of claims 12 to 13.
20. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method of any one of claims 14 to 18.
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| CN112286841B (en) * | 2019-07-23 | 2022-04-19 | 珠海零边界集成电路有限公司 | Data synchronization method and register |
| CN110971333B (en) * | 2019-11-28 | 2021-09-07 | 四川福帆科技有限公司 | Two-way time synchronization system and method based on free space laser communication |
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