CN112558106A - Satellite-borne atmospheric ocean high repetition frequency laser radar system and detection method - Google Patents
Satellite-borne atmospheric ocean high repetition frequency laser radar system and detection method Download PDFInfo
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- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
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- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
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- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
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- G—PHYSICS
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
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- G—PHYSICS
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
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- G01S7/483—Details of pulse systems
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- G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
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Abstract
The invention provides a satellite-borne atmosphere ocean high repetition frequency laser radar system and a detection method, and the system comprises a high repetition frequency laser radar arranged on a satellite, wherein the high repetition frequency laser radar comprises a three-wavelength laser emission subsystem, an optical axis adjusting subsystem electrically connected with the three-wavelength laser emission subsystem, a receiving optical subsystem arranged on one side of the three-wavelength laser emission subsystem, and a comprehensive control and signal processing subsystem electrically connected with the three-wavelength laser emission subsystem and interacting with a satellite platform in remote measurement and remote control. The invention provides a satellite-borne atmosphere marine high repetition frequency laser radar system and a detection method for solving the problem of comprehensive observation of gas, sea and underwater.
Description
Technical Field
The invention relates to the technical field of measurement and testing, in particular to a satellite-borne atmospheric marine high repetition frequency laser radar system and a detection method.
Background
Cloud, aerosol, etc. are the main factors affecting the earth's radiation, and affecting the global climate and weather changes. Through satellite-borne cloud-aerosol detection, a vertical section of the global aerosol horizontal flux can be inverted, and the method has great significance for meteorological climate research. The shallow sea water depth measurement is a main component of ocean mapping, can provide important basic data for sea chart compilation, navigation safety, ocean demarcation, port construction and ocean fishery, and the space-based active laser load is the only remote sensing means which can realize high-precision water depth direct measurement on a satellite-borne platform at the present stage, and can acquire near-shore terrain data, water depth data, island and change conditions near mudflats of a global sea area at high precision. Meanwhile, due to mutual influence and mutual constraint of atmospheric-ocean-land radiation, the comprehensive environmental element detection with high space-time consistency is realized by common platform cooperative observation.
In the space-based marine three-dimensional environment laser detection load direction, no special underwater detection laser load exists at the present stage of Europe and America, but the Europe and America and other countries complete space tests of multiple laser remote sensing loads by relying on various test platforms such as space shuttles, satellites and the like, and successfully and plan to emit multiple laser radar loads, wherein the multiple laser radar loads comprise a satellite-borne laser altimeter, a satellite-borne cloud-aerosol laser radar, a satellite-borne atmospheric power observation and atmospheric composition detection laser radar and the like. For years, with the support of various national projects, China's satellite-borne laser radar technology has been greatly developed and has had a deep technical reserve. Starting from the laser altimeter carried on the "ChangE" moon-exploring series satellite, the laser radar load for land surveying and mapping and atmospheric surveying is in orbit or in research at present. However, the laser radar technology is still blank for solving the problem of comprehensive observation of atmosphere, sea surface and underwater.
Disclosure of Invention
The invention provides a satellite-borne atmosphere marine high repetition frequency laser radar system and a detection method for solving the problem of comprehensive observation of gas, sea and underwater.
The invention provides a satellite-borne atmosphere ocean high-repetition-frequency laser radar system which comprises a high-repetition-frequency laser radar arranged on a satellite, wherein the high-repetition-frequency laser radar comprises a three-wavelength laser emission subsystem, an optical axis adjusting subsystem electrically connected with the three-wavelength laser emission subsystem, a receiving optical subsystem arranged on one side of the three-wavelength laser emission subsystem, and an integrated control and signal processing subsystem which is electrically connected with the three-wavelength laser emission subsystem, the optical axis adjusting subsystem and the receiving optical subsystem and is in remote measurement and remote control interaction with a satellite platform;
the three-wavelength laser emission subsystem is used for emitting laser pulses with three wavelengths, splitting, expanding, combining into a beam of laser pulses and outputting the laser pulses to the atmosphere, the seawater and the undersea target at a fixed angle, the optical axis adjusting subsystem is used for adjusting the laser pulses after expanding, expanding and combining to point to the direction coaxial with the receiving optical subsystem, the receiving optical subsystem is used for receiving the backscattering signals of the atmosphere, the seawater and the undersea target and splitting and separating colors, the comprehensive control and signal processing subsystem is used for receiving the analog signals sent by the receiving optical subsystem and screening and framing and then sending the analog signals to the satellite platform.
The invention relates to a satellite-borne atmosphere ocean high-repetition-frequency laser radar system, which is used as a preferred mode, wherein a three-wavelength laser emission subsystem comprises a three-wavelength high-repetition-frequency laser, a light splitting and beam expanding adjusting module arranged on one side of the three-wavelength high-repetition-frequency laser and a laser controller electrically connected with the three-wavelength high-repetition-frequency laser, and the laser controller is electrically connected with an integrated control and signal processing subsystem;
the three-wavelength high-frequency-heavy laser is used for emitting 355nm laser pulses, 532nm laser pulses and 1064nm laser pulses to the light-splitting and beam-expanding adjusting module, the light-splitting and beam-expanding adjusting module is used for receiving the laser pulses emitted by the three-wavelength high-frequency-heavy laser, splitting the beams according to the wavelengths, expanding the beams respectively, compressing the divergence angles of the laser, combining the beams into a beam of laser pulses and outputting the beam of laser pulses to the atmosphere, seawater and an undersea target, and the laser controller is used for generating pumping current pulses under the synchronous control of the comprehensive management unit so as to drive the three-wavelength high-frequency-heavy laser to emit.
The invention relates to a satellite-borne atmosphere ocean high-repetition-frequency laser radar system, which is used as an optimal mode, wherein a pumping source of a three-wavelength high-repetition-frequency laser is a laser diode for optical fiber coupling output, an end surface pump Nd is a YAG laser medium, a BBO electro-optical Q switch is inserted into a resonant cavity of the pumping source to construct a laser oscillation stage, and seed laser output of kHz level, narrow pulse width and high beam quality is obtained; (ii) a YAG medium is used as laser amplification stage, and the amplification stage adopts two-stage amplification; the 1064nm laser pulse output after two-stage amplification is subjected to frequency multiplication by using an LBO crystal to obtain 532nm laser pulse output, the 1064nm laser pulse output after two-stage amplification is subjected to frequency multiplication by using the LBO crystal to obtain 355nm laser pulse output, and the 355nm, 532nm and 1064nm laser pulses are output on a common optical axis;
the beam splitting and expanding adjustment module uses a high damage threshold dichroic mirror to split 355nm laser pulses, 532nm laser pulses and 1064nm laser pulses into three beams.
The invention relates to a satellite-borne atmosphere ocean high repetition frequency laser radar system, which is used as a preferred mode, wherein an optical axis adjusting subsystem comprises an optical axis adjusting mechanism arranged on one side of a three-wavelength laser emission subsystem and an optical axis adjusting driver electrically connected with the optical axis adjusting mechanism;
the optical axis adjusting mechanism is used for adjusting the laser pulse after the beam expanding and combining to point to the direction coaxial with the receiving optical subsystem, and the optical axis adjusting driver is used for driving and controlling the optical axis adjusting mechanism;
the receiving optical subsystem comprises a receiving telescope arranged on one side of the three-wavelength laser emission subsystem, a receiving optical unit arranged on one side of the receiving telescope, a photoelectric detection unit and a signal conditioning unit, wherein the photoelectric detection unit and the signal conditioning unit are sequentially electrically connected with the optical unit;
the receiving telescope is used for receiving the backscattering signals of the atmosphere, the seawater and the undersea target according to time sequence and outputting the backscattering signals to the receiving optical unit, the receiving optical unit is used for receiving the backscattering signals, splitting, separating colors and filtering narrow bands and then respectively introducing into 355nm vertical polarization channels, the optical signal is output to the photoelectric detection unit after the 355nm parallel polarization channel, the 532nm vertical polarization channel and the 1064nm channel, the photoelectric detection unit is used for detecting and receiving the optical signal output by the optical unit and respectively converting the optical signal into an electric signal to be output to the signal conditioning unit, the signal conditioning unit is used for receiving the electric signal sent by the photoelectric detection unit, converting the electric signal into an analog signal after multi-channel multi-stage amplification conditioning and outputting the analog signal to the comprehensive control and signal processing subsystem, and each detection channel is branched into an atmospheric photon signal channel and an ocean analog signal channel after conditioning.
The satellite-borne atmospheric ocean high-repetition-frequency laser radar system is characterized in that as an optimal mode, a Cassegrain telescope structure is used as a receiving telescope, the caliber of the receiving telescope is 500-1000 mm, and laser pulses emitted by a three-wavelength laser emission subsystem and the receiving telescope are coaxially output through a turning reflector;
the receiving optical unit receives the backscattering signals of the atmosphere, the seawater and the undersea target by using a dichroic mirror, a polarizing beam splitter and a turning reflector, and filters the background light by using a narrow-band optical filter and an F-P standard distance combination mode;
the photoelectric detection unit detects optical signals of a 355nm vertical polarization channel, a 355nm parallel polarization channel, a 532nm parallel polarization channel and a 532nm vertical polarization channel by using a photomultiplier, and the photoelectric detection unit detects optical signals of a 1064nm channel by using a Geiger mode avalanche photodiode;
the signal conditioning unit is used for conditioning an electric signal output by a single detector of the photoelectric detection unit by adopting a multi-channel multi-stage amplification structure, and respectively carrying out conditioning on a bandwidth of 300MHz and a gain of 10dB to generate a first analog signal and conditioning on a bandwidth of 150MHz and a gain of 20dB to generate a second analog signal, wherein the first analog signal is used for photon counting detection, and the second analog signal is used for simulating echo detection.
The invention relates to a satellite-borne atmosphere ocean high repetition frequency laser radar system, which is used as an optimal mode, wherein a comprehensive control and signal processing subsystem comprises a comprehensive management unit which is remotely measured and remotely controlled to interact with a satellite platform and a data acquisition and processing unit which is electrically connected with a receiving optical subsystem, and the comprehensive management unit is electrically connected with a three-wavelength laser emission subsystem, an optical axis adjusting subsystem and the receiving optical subsystem;
the comprehensive management unit is used for receiving a driving instruction of the satellite platform and controlling the three-wavelength laser emission subsystem to emit laser pulse, and the comprehensive management unit is used for power supply and distribution, time sequence and instruction control of the high repetition frequency laser radar; the data acquisition processing unit comprises a data processing unit, a high-speed comparator, an FPGA and an analog-to-digital converter, the data processing unit is used for generating a sampling wave gate according to a sampling time sequence, the high-speed comparator and the FPGA are used for screening optical signals in the wave gate, the analog-to-digital converter and the FPGA are used for sampling analog signals, and processed results are framed and sent to the satellite platform to be downloaded to the ground.
As an optimal mode, the photon counting detection counting rate of the data acquisition and processing unit is larger than 50MCPS, the analog sampling rate of the data acquisition and processing unit is larger than 1GHz, and the effective digit of the data acquisition and processing unit is superior to 12 bits.
The satellite-borne atmosphere ocean high repetition frequency laser radar system provided by the invention has the advantages that as an optimal mode, the fixed angle is 3-5 degrees between the laser pulse emission and the satellite lower point.
The invention provides a detection method of a satellite-borne atmospheric marine high repetition frequency laser radar system, which comprises the following steps:
s1, adjusting the optical axis: the optical axis adjusting driver controls the optical axis adjusting mechanism to direct the laser pulses output by the three-wavelength laser emission subsystem to the direction coaxial with the receiving optical subsystem; emitting laser pulses to step S2, obtaining a detection echo gate delay to step S3, and performing step S2 and step S3 simultaneously;
s2, emitting laser pulses: the integrated control and signal processing subsystem controls the three-wavelength high-repetition-frequency laser to emit high-repetition-frequency laser pulses under the drive of a pulse-per-second falling edge provided by the satellite platform, wherein the pulse-per-second falling edge is T0;
s3, obtaining detection echo gate delay: the integrated control and signal processing subsystem generates a sampling wave gate under the trigger of a pulse-per-second falling edge T0, delays to generate a marine detection emission pulse sampling wave gate, and calculates marine detection echo wave gate delay and atmospheric detection wave gate delay according to the height of a satellite platform;
s4, obtaining atmospheric optical parameter information and marine underwater topography information: the data acquisition processing unit performs analog-to-digital conversion and cache on an ocean analog signal channel in an ocean detection emission pulse sampling wave gate and an ocean detection echo wave gate according to a sampling wave gate; the data acquisition processing unit discriminates and counts photon pulses of the atmospheric photon signal channel in an atmospheric detection wave gate according to the sampling wave gate, frames the processed result and the state information of the high repetition frequency laser radar, and sends the framed result and the state information of the high repetition frequency laser radar to a satellite platform to be downloaded to the ground for subsequent inversion processing, so that atmospheric optical parameter information and ocean underwater topography information are obtained.
The invention relates to a detection method of a satellite-borne atmosphere ocean high repetition frequency laser radar system, which is used as an optimal mode,
in step S2, the emission frequency of the three-wavelength high-frequency and heavy-frequency laser is 1 kHz; the time delay between the light emitting time of the three-wavelength high-repetition-frequency laser and the pulse-per-second falling edge T0 is fixed to be 200us +/-100 ns;
in step S3, delaying 199.75us to generate a sampling wave gate of ocean exploration emission pulses, wherein the width of the sampling wave gate of the ocean exploration emission pulses is 500 ns;
in step S3, calculating the sea detection echo wave gate time delay t1 according to the platform height h sent by the satellite platform in real time:
t1 ═ 0.15+200000, where the ocean sounding echo gate width is 30 us;
in step S3, the atmospheric sounding gate delay t2 is calculated according to the platform height h:
t2 ═ 0.15+200000, where the atmospheric probe wave gate width is 270 us.
The invention has the following advantages:
(1) the system adopts high repetition frequency and low monopulse energy emission, simulation and single photon cooperative detection and atmospheric marine signal single-channel time-sharing acquisition, realizes the simultaneous acquisition of multiple factors of global atmospheric, sea surface and underwater environment information, and expands the detection efficiency of the system. Such satellite-borne lidar has not been reported internationally.
(2) By adopting the high repetition frequency multi-wavelength emission technology, the emission average power is not influenced on the detection efficiency, the laser emission peak power is effectively reduced, the damage threshold requirement on optical elements in a laser cavity is reduced, the reliability of the laser is improved, the satellite-borne long service life requirement is met, meanwhile, the ground horizontal resolution of the system can be improved by high repetition frequency emission, and the information acquisition efficiency is improved.
(3) By adopting the simulation and single photon cooperative detection technology, different signal conditioning channels are configured by a single detector, and the simulation sampling detection of ocean strong scattering echoes and the photon counting detection of atmosphere weak scattering echoes are realized simultaneously, so that the detection dynamic range of the system is greatly increased, and the detection capability of weak signals is improved.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment 1 of a satellite-borne atmospheric marine high repetition frequency lidar system;
FIG. 2 is a schematic structural diagram of an embodiment 2-3 of a satellite-borne atmospheric marine high repetition frequency lidar system;
FIG. 3 is a flow chart of a detection mode of a satellite-borne atmospheric marine high-repetition-frequency laser radar system.
Reference numerals:
1. a three-wavelength laser emission subsystem; 11. a three-wavelength high-repetition-frequency laser; 12. a light splitting and beam expanding adjusting module; 13. a laser controller; 2. an optical axis adjustment subsystem; 21. an optical axis adjusting mechanism; 22. an optical axis adjustment driver; 3. a receive optical subsystem; 31. a receiving telescope; 32. a receiving optical unit; 33. a photodetecting unit; 34. a signal conditioning unit; 4. a comprehensive control and signal processing subsystem; 41. a comprehensive management unit; 42. and a data acquisition and processing unit.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Example 1
As shown in fig. 1, a satellite-borne atmospheric marine high repetition frequency laser radar system comprises a high repetition frequency laser radar arranged on a satellite, wherein the high repetition frequency laser radar comprises a three-wavelength laser emission subsystem 1, an optical axis adjustment subsystem 2 electrically connected with the three-wavelength laser emission subsystem 1, a receiving optical subsystem 3 arranged on one side of the three-wavelength laser emission subsystem 1, and an integrated control and signal processing subsystem 4 electrically connected with the three-wavelength laser emission subsystem 1, the optical axis adjustment subsystem 2 and the receiving optical subsystem 3 and interacting with a satellite telemetry platform in a remote control manner;
the three-wavelength laser emission subsystem 1 is used for emitting laser pulses with three wavelengths, splitting, expanding, combining and outputting the laser pulses into a beam of laser pulses and outputting the laser pulses to atmosphere, seawater and undersea targets at a fixed angle, the optical axis adjusting subsystem 2 is used for adjusting the laser pulses after expanding, expanding and combining to be directed to the direction coaxial with the receiving optical subsystem 3, the receiving optical subsystem 3 is used for receiving backscattering signals of the atmosphere, the seawater and the undersea targets, splitting, color separation, narrow-band filtering and signal conditioning and converting the signals into analog signals to be output to the comprehensive control and signal processing subsystem 4, the comprehensive control and signal processing subsystem 4 is used for receiving driving instructions of a satellite platform and controlling the three-wavelength laser emission subsystem 1 to emit the laser pulses, the comprehensive control and signal processing subsystem 4 is used for power supply and distribution, timing and instruction control of the high-repetition-frequency laser radar, and the comprehensive control and signal processing subsystem 4 is used for receiving the analog signals sent by the receiving optical subsystem And sending the data to a satellite platform.
Example 2
As shown in fig. 2, a satellite-borne atmospheric marine high repetition frequency laser radar system comprises a high repetition frequency laser radar arranged on a satellite, wherein the high repetition frequency laser radar comprises a three-wavelength laser emission subsystem 1, an optical axis adjustment subsystem 2 electrically connected with the three-wavelength laser emission subsystem 1, a receiving optical subsystem 3 arranged on one side of the three-wavelength laser emission subsystem 1, and an integrated control and signal processing subsystem 4 electrically connected with the three-wavelength laser emission subsystem 1, the optical axis adjustment subsystem 2 and the receiving optical subsystem 3 and interacting with a satellite telemetry platform in a remote control manner;
the three-wavelength laser emission subsystem 1 is used for emitting laser pulses with three wavelengths, splitting, expanding, combining into a beam of laser pulses and outputting the laser pulses to the atmosphere, seawater and undersea targets at a fixed angle, the fixed angle is that the laser pulses are emitted and the undersea point is kept at 3-5 degrees, the optical axis adjusting subsystem 2 is used for adjusting the direction of the laser pulses after being expanded and combined to the direction coaxial with the receiving optical subsystem 3, the receiving optical subsystem 3 is used for receiving the back scattering signals of the atmosphere, seawater and undersea targets, splitting, color separation, narrow-band filtering and signal conditioning are carried out on the back scattering signals, converting the back scattering signals into analog signals and outputting the analog signals to the comprehensive control and signal processing subsystem 4, the comprehensive control and signal processing subsystem 4 is used for receiving driving instructions of a satellite platform and controlling the three-wavelength laser emission subsystem 1 to emit laser pulses, and the comprehensive control and signal processing subsystem 4, The time sequence and instruction control, integrated control and signal processing subsystem 4 is used for receiving the analog signals sent by the optical subsystem 3, screening and framing the analog signals and sending the analog signals to the satellite platform;
the three-wavelength laser emission subsystem 1 comprises a three-wavelength high-frequency and heavy-frequency laser 11, a light splitting and beam expanding adjusting module 12 arranged on one side of the three-wavelength high-frequency and heavy-frequency laser 11 and a laser controller 13 electrically connected with the three-wavelength high-frequency and heavy-frequency laser 11, wherein the laser controller 13 is electrically connected with the comprehensive control and signal processing subsystem 4;
the three-wavelength high-gravity laser 11 is used for emitting 355nm laser pulses, 532nm laser pulses and 1064nm laser pulses to the light-splitting and beam-expanding adjusting module 12, the light-splitting and beam-expanding adjusting module 12 is used for receiving the laser pulses emitted by the three-wavelength high-gravity laser 11, splitting the beams according to the wavelengths, respectively expanding the beams and compressing the divergence angles of the laser, combining the beams into a beam of laser pulses, and outputting the beam of laser pulses to the atmosphere, seawater and an undersea target, and the laser controller 13 is used for generating pumping current pulses under the synchronous control of the comprehensive management unit 4 to drive the three-wavelength high-gravity laser 11 to emit the laser pulses;
the pumping source of the three-wavelength high-frequency and heavy-frequency laser 11 is a laser diode LD (laser diode) coupled and output by an optical fiber, the end face pumps Nd, namely a YAG laser medium, and a BBO (barium boron oxide) electro-optical Q switch is inserted into a resonant cavity of the pumping source to construct a laser oscillation stage; the three-wavelength high-frequency and heavy-frequency laser 11 uses a laser diode end pump Nd and YAG medium which are coupled and output by optical fibers as a laser amplification stage, and the amplification stage adopts two-stage amplification; frequency multiplication is carried out on 1064nm laser pulses output after two-stage amplification by using an LBO crystal to obtain 532nm laser pulse output, and sum frequency is carried out on the 1064nm laser pulses output after two-stage amplification by using the LBO crystal to obtain 355nm laser pulse output;
the beam splitting and expanding adjustment module 12 uses a high damage threshold dichroic mirror to split 355nm laser pulses, 532nm laser pulses and 1064nm laser pulses into three beams;
the optical axis adjusting subsystem 2 comprises an optical axis adjusting mechanism 21 arranged on one side of the three-wavelength laser emitting subsystem 1 and an optical axis adjusting driver 22 electrically connected with the optical axis adjusting mechanism 21;
the optical axis adjusting mechanism 21 is used for adjusting the laser pulse after beam expansion and combination to point to the direction coaxial with the receiving optical subsystem 3, and the optical axis adjusting driver 22 is used for driving and controlling the optical axis adjusting mechanism 21;
the receiving optical subsystem 3 comprises a receiving telescope 31 arranged on one side of the three-wavelength laser emission subsystem 1, a receiving optical unit 32 arranged on one side of the receiving telescope 31, a photoelectric detection unit 33 and a signal conditioning unit 34 which are sequentially and electrically connected with the optical unit 32;
the receiving telescope 31 is used for receiving the backscattering signals of the atmosphere, the seawater and the undersea target according to time sequence and outputting the backscattering signals to the receiving optical unit 32, the receiving optical unit 32 is used for receiving the backscattering signals, splitting light, separating color and filtering narrow band, then respectively introducing 355nm vertical polarization channels, outputting optical signals to the photoelectric detection unit 33 after the 355nm parallel polarization channel, the 532nm vertical polarization channel and the 1064nm channel, wherein the photoelectric detection unit 33 is used for detecting and receiving optical signals output by the optical unit 32 and respectively converting the optical signals into electric signals to be output to the signal conditioning unit 34, the signal conditioning unit 34 is used for receiving the electric signals sent by the photoelectric detection unit 33, converting the electric signals into analog signals after multi-channel multi-stage amplification conditioning and outputting the analog signals to the comprehensive control and signal processing subsystem 4, and each detection channel is divided into an atmospheric photon signal channel and an ocean analog signal channel after conditioning;
the receiving telescope 31 adopts a Cassegrain telescope structure, the caliber of the receiving telescope 31 is 500-1000 mm, and laser pulses transmitted by the three-wavelength laser transmitting subsystem 1 and the receiving telescope 31 are coaxially output through a turning reflector;
the receiving optical unit 32 receives the backscattering signals of the atmosphere, the seawater and the undersea target by using a dichroic mirror, a polarizing beam splitter and a turning mirror, and the receiving optical unit 32 filters the background light by using a narrow-band optical filter and an F-P standard distance combination mode;
the photoelectric detection unit 33 detects optical signals of a 355nm vertical polarization channel, a 355nm parallel polarization channel, a 532nm parallel polarization channel and a 532nm vertical polarization channel by using a photomultiplier, and the photoelectric detection unit 33 detects optical signals of a 1064nm channel by using a Geiger-mode avalanche photodiode;
the signal conditioning unit 34 conditions the electric signals output by the single detector of the photoelectric detection unit 33 by adopting a multi-channel multi-stage amplification structure, and respectively conditions the bandwidth of 300MHz and the gain of 10dB to generate a first analog signal and conditions the bandwidth of 150MHz and the gain of 20dB to generate a second analog signal, wherein the first analog signal is used for photon counting detection, and the second analog signal is used for simulating echo detection;
the integrated control and signal processing subsystem 4 comprises an integrated management unit 41 which is in remote measurement and remote control interaction with a satellite platform and a data acquisition and processing unit 42 which is electrically connected with the receiving optical subsystem 3, wherein the integrated management unit 41 is electrically connected with the three-wavelength laser emission subsystem 1, the optical axis adjusting subsystem 2 and the receiving optical subsystem 3;
the comprehensive management unit 41 is used for receiving a driving instruction of the satellite platform and controlling the three-wavelength laser emission subsystem 1 to emit laser pulses, and the comprehensive management unit 41 is used for power supply and distribution, time sequence and instruction control of the high repetition frequency laser radar; the data acquisition processing unit 42 comprises a data processing unit, a high-speed comparator, an FPGA and an analog-to-digital converter, wherein the data processing unit is used for generating a sampling wave gate according to a sampling time sequence, screening optical signals in the wave gate through the high-speed comparator and the FPGA, sampling the analog signals by the analog-to-digital converter and the FPGA, and framing the processed results to send the processed results to the satellite platform for downloading to the ground;
the photon counting detection counting rate of the data acquisition processing unit 42 is more than 50MCPS, the analog sampling rate of the data acquisition processing unit 42 is more than 1GHz, and the effective digit of the data acquisition processing unit 42 is better than 12 bits.
Example 3
As shown in fig. 2, a satellite-borne atmospheric marine high repetition frequency laser radar system comprises a high repetition frequency laser radar arranged on a satellite, wherein the high repetition frequency laser radar comprises a three-wavelength laser emission subsystem 1, an optical axis adjustment subsystem 2 electrically connected with the three-wavelength laser emission subsystem 1, a receiving optical subsystem 3 arranged on one side of the three-wavelength laser emission subsystem 1, and an integrated control and signal processing subsystem 4 electrically connected with the three-wavelength laser emission subsystem 1 and interacting with a satellite platform in remote measurement and remote control;
the three-wavelength laser emission subsystem 1 is used for emitting three-wavelength laser pulses, splitting, expanding, combining into one laser pulse and outputting the laser pulse to the atmosphere, seawater and an undersea target at a fixed angle, wherein the fixed angle is 3-5 degrees for laser pulse emission and an undersea point, and the saturation of a detection channel caused by sea surface Fresnel reflection is avoided; the optical axis adjusting subsystem 2 is used for adjusting the laser pulse after beam expanding and combining to point to the direction coaxial with the receiving optical subsystem 3, the receiving optical subsystem 3 is used for receiving the back scattering signals of the atmosphere, the seawater and the undersea target, splitting, color separating, narrow-band filtering and signal conditioning are carried out on the back scattering signals, the back scattering signals are converted into analog signals, the analog signals are output to the comprehensive control and signal processing subsystem 4, the comprehensive control and signal processing subsystem 4 is used for receiving driving instructions of a satellite platform and controlling the three-wavelength laser transmitting subsystem 1 to transmit laser pulses, the comprehensive control and signal processing subsystem 4 is used for power supply, distribution, time sequence and instruction control of the high-repetition-frequency laser radar, and the comprehensive control and signal processing subsystem 4 is used for receiving the analog signals transmitted by the receiving optical subsystem 3 and screening and framing and then transmitting;
the three-wavelength laser emission subsystem 1 comprises a three-wavelength high-frequency and heavy-frequency laser 11, a light splitting and beam expanding adjusting module 12 arranged on one side of the three-wavelength high-frequency and heavy-frequency laser 11 and a laser controller 13 electrically connected with the three-wavelength high-frequency and heavy-frequency laser 11, wherein the laser controller 13 is electrically connected with the comprehensive control and signal processing subsystem 4;
the three-wavelength high-gravity laser 11 is used for emitting 355nm laser pulses, 532nm laser pulses and 1064nm laser pulses to the light-splitting and beam-expanding adjusting module 12, the light-splitting and beam-expanding adjusting module 12 is used for receiving the laser pulses emitted by the three-wavelength high-gravity laser 11, splitting the beams according to the wavelengths, respectively expanding the beams and compressing the divergence angles of the laser, combining the beams into a beam of laser pulses, and outputting the beam of laser pulses to the atmosphere, seawater and an undersea target, and the laser controller 13 is used for generating pumping current pulses under the synchronous control of the comprehensive management unit 4 to drive the three-wavelength high-gravity laser 11 to emit the laser pulses;
the pumping source of the three-wavelength high-frequency and heavy-frequency laser 11 is a laser diode LD (laser diode) coupled and output by an optical fiber, the end face pumps Nd, namely a YAG laser medium, and a BBO (barium boron oxide) electro-optical Q switch is inserted into a resonant cavity of the pumping source to construct a laser oscillation stage; the three-wavelength high-frequency and heavy-frequency laser 11 uses a laser diode end pump Nd and YAG medium which are coupled and output by optical fibers as a laser amplification stage, and the amplification stage adopts two-stage amplification; the 1064nm laser pulse output after two-stage amplification is subjected to frequency doubling by using an LBO crystal to obtain 532nm laser pulse output, the 1064nm laser pulse output after two-stage amplification is subjected to frequency doubling by using the LBO crystal to obtain 355nm laser pulse output, the single pulse energy is respectively 2mJ, 8mJ and 8mJ, and the laser emission repetition frequency is 1000 Hz;
by applying the high repetition frequency laser emission technology, the detection efficiency is not influenced by the emission average power, the laser emission peak power and the monopulse energy are effectively reduced, the laser radar marine detection avoids the saturation of a detection system, and meanwhile, the signal-to-noise ratio required by atmospheric detection is improved by means of photon counting and time accumulation, so that the laser radar can simultaneously realize the atmospheric, water surface and underwater target detection;
the beam splitting and expanding adjustment module 12 uses a dichroic mirror with a high damage threshold to split 355nm laser pulses, 532nm laser pulses and 1064nm laser pulses into three beams, and the three beams are expanded by a beam expander and then combined into one beam for output. The specific method is that the wavelength beam splitting of the emergent laser is realized through a dichroic mirror, the compression of the divergence angle of the laser is realized through a beam expanding lens, and the beam combination is realized through a 45-degree turning reflecting mirror after the beam expanding, so that the design difficulty of the beam expanding lens caused by the chromatic aberration of different wavelengths can be reduced;
the optical axis adjusting subsystem 2 comprises an optical axis adjusting mechanism 21 arranged on one side of the three-wavelength laser emitting subsystem 1 and an optical axis adjusting driver 22 electrically connected with the optical axis adjusting mechanism 21;
the optical axis adjusting mechanism 21 is used for adjusting the laser pulse after beam expansion and combination to point to the direction coaxial with the receiving optical subsystem 3, and the optical axis adjusting driver 22 is used for driving and controlling the optical axis adjusting mechanism 21; the optical axis adjusting subsystem 2 comprises an optical axis adjusting driver 22 and an optical axis adjusting mechanism 21, the optical axis adjusting mechanism 21 consists of a two-axis adjusting reflector, a stepping motor, a high-precision encoder, a precision reducer and a precision lead screw, the optical axis adjusting driver 22 provides driving current for the motor through a driving circuit, the precision lead screw is driven by the precision reducer to enable the two-axis adjusting reflector to rotate, and angle rotation information is read by the high-precision encoder in real time to realize closed-loop control of the adjusting mechanism; the two-axis adjustment of the optical axis adjusting mechanism 22 drives the combined 355nm, 532nm and 1064nm emitted laser beams to point, the adjustment range of the azimuth direction and the pitch direction is +/-1 DEG, the adjustment precision is 5 mu rad, and the coaxial output with the receiving telescope 31 is realized by adjusting echo data to the maximum extent;
the receiving optical subsystem 3 comprises a receiving telescope 31 arranged on one side of the three-wavelength laser emission subsystem 1, a receiving optical unit 32 arranged on one side of the receiving telescope 31, a photoelectric detection unit 33 and a signal conditioning unit 34 which are sequentially and electrically connected with the optical unit 32;
the receiving telescope 31 is used for receiving the backscattering signals of the atmosphere, the seawater and the undersea target according to time sequence and outputting the backscattering signals to the receiving optical unit 32, the receiving optical unit 32 is used for receiving the backscattering signals, splitting light, separating color and filtering narrow band, then respectively introducing 355nm vertical polarization channels, outputting optical signals to the photoelectric detection unit 33 after the 355nm parallel polarization channel, the 532nm vertical polarization channel and the 1064nm channel, wherein the photoelectric detection unit 33 is used for detecting and receiving optical signals output by the optical unit 32 and respectively converting the optical signals into electric signals to be output to the signal conditioning unit 34, the signal conditioning unit 34 is used for receiving the electric signals sent by the photoelectric detection unit 33, converting the electric signals into analog signals after multi-channel multi-stage amplification conditioning and outputting the analog signals to the comprehensive control and signal processing subsystem 4, and each detection channel is divided into an atmospheric photon signal channel and an ocean analog signal channel after conditioning;
the receiving telescope 31 adopts a Cassegrain telescope structure, the caliber of the receiving telescope 31 is 500-1000 mm, and laser pulses transmitted by the three-wavelength laser transmitting subsystem 1 and the receiving telescope 31 are coaxially output through a turning reflector; the receiving telescope 31 realizes that the parallel light enters the parallel light and exits, the telescope mainly comprises a primary mirror assembly, a secondary mirror assembly, an outer lens hood, a supporting structure and a telescope main structure, and the emitted laser is converted and coaxially output with a 45-degree conversion reflector behind the secondary mirror of the receiving telescope 31 after being converted by a beam splitting and expanding adjusting module;
the receiving optical unit 32 receives the backscattering signals of the atmosphere, the seawater and the undersea target by using a dichroic mirror, a polarizing beam splitter and a turning mirror, and the receiving optical unit 32 filters the background light by using a narrow-band optical filter and an F-P standard distance combination mode;
a field diaphragm is arranged on the focal plane of the receiving telescope 31, a target scattered light signal is collimated into parallel light by a collimating mirror after passing through the scattering diaphragm, then 355nm wavelength light is separated out through reflection of a three-wavelength dichroic mirror, and then enters a 355nm detector for photoelectric conversion after being filtered by a 355nm F-P cavity, a 355nm narrow-band optical filter and focused by a 355nm focusing mirror; 532nm and 1064nm light is transmitted by a three-wavelength dichroic mirror, 532nm light is reflected and separated by a dual-wavelength dichroic mirror and is incident to a 532nm F-P cavity for background light filtering, the filtered light passes through a polarization beam splitter, a light beam in the P polarization direction in the light beam is transmitted by the polarization beam splitter, then filtered by a 532nm narrow-band filter, and enters a 532nm P detector for photoelectric conversion; the light beam in the S polarization direction in the light beam is reflected at 90 degrees on the surface of the polarization beam splitter, enters a 532nm S turning reflector, is filtered by a 532nm narrow-band filter, enters a 532nm focusing mirror and then enters a 532nm S detector for photoelectric conversion; 1064nm light is separated by transmission after passing through the dual-wavelength dichroic mirror, enters the 1064nm narrow-band filter and the 1064nm focusing mirror and then enters the 1064nm analog detector for photoelectric conversion. The F-P cavities of the 532nm and 355nm channels are combined with the narrow-band filter to realize the filtering bandwidth of 50pm, the 1064nm channel has small influence due to background light, and the 0.3nm filter is adopted to realize background light inhibition;
the photoelectric detection unit 33 detects optical signals of a 355nm vertical polarization channel, a 355nm parallel polarization channel, a 532nm parallel polarization channel and a 532nm vertical polarization channel by using a photomultiplier, and the photoelectric detection unit 33 detects optical signals of a 1064nm channel by using a Geiger-mode avalanche photodiode; photomultiplier tube selectionThe 9880U PMT of HAMAMTSU company of Japan can realize the responsivity of 50mA/W and 1 x 106A gain of (d); the avalanche photodiode selects SPCM-AQRH-15 of Laser components, and the dark noise of the avalanche photodiode can realize single-photon magnitude detection due to 50 CPS/s;
the signal conditioning unit 34 conditions the electric signals output by the single detector of the photoelectric detection unit 33 by adopting a multi-channel multi-stage amplification structure, and respectively conditions the bandwidth of 300MHz and the gain of 10dB to generate a first analog signal and conditions the bandwidth of 150MHz and the gain of 20dB to generate a second analog signal, wherein the first analog signal is used for photon counting detection, and the second analog signal is used for simulating echo detection;
the integrated control and signal processing subsystem 4 comprises an integrated management unit 41 which is in remote measurement and remote control interaction with a satellite platform and a data acquisition and processing unit 42 which is electrically connected with the receiving optical subsystem 3, wherein the integrated management unit 41 is electrically connected with the three-wavelength laser emission subsystem 1, the optical axis adjusting subsystem 2 and the receiving optical subsystem 3;
the comprehensive management unit 41 is used for receiving a driving instruction of the satellite platform and controlling the three-wavelength laser emission subsystem 1 to emit laser pulses, and the comprehensive management unit 41 is used for power supply and distribution, time sequence and instruction control of the high repetition frequency laser radar; the data acquisition processing unit 42 comprises a data processing unit, a high-speed comparator, an FPGA and an analog-to-digital converter, wherein the data processing unit is used for generating a sampling wave gate according to a sampling time sequence, screening optical signals in the wave gate through the high-speed comparator and the FPGA, sampling the analog signals by the analog-to-digital converter and the FPGA, and framing the processed results to send the processed results to the satellite platform for downloading to the ground;
the comprehensive management unit realizes remote measurement and instruction interaction with the satellite platform by adopting a 1553B bus; the power on and off of other single machines in the radar are controlled by adopting an OC door; the bidirectional 422 asynchronous serial port is adopted to realize instruction control, parameter issuing and telemetering data collection with other single machines in the radar; meanwhile, under the drive of a pulse per second falling edge (time T0) provided by a satellite platform, a radar sampling gate is generated and sent to a data acquisition processing unit; thereby realizing the radar integrated management and control function;
the photon counting detection counting rate of the data acquisition processing unit 42 is more than 50MCPS, the analog sampling rate of the data acquisition processing unit 42 is more than 1GHz, and the effective digit of the data acquisition processing unit 42 is better than 12 bits.
As shown in fig. 3, the detection method of embodiments 1 to 3 includes the steps of:
s1, adjusting the optical axis: the optical axis adjusting driver 22 controls the optical axis adjusting mechanism 21 to direct the laser pulses output by the three-wavelength laser emission subsystem 1 to a direction coaxial with the receiving optical subsystem 3; emitting laser pulses to step S2, obtaining a detection echo gate delay to step S3, and performing step S2 and step S3 simultaneously;
s2, emitting laser pulses: the integrated control and signal processing subsystem 4 controls the three-wavelength high-repetition-frequency laser 11 to emit high-repetition-frequency laser pulses under the drive of a pulse-per-second falling edge provided by the satellite platform, wherein the pulse-per-second falling edge is T0; the emission frequency of the three-wavelength high-repetition laser 11 is 1 kHz; the time delay between the light emitting time of the three-wavelength high-repetition laser 11 and the pulse-per-second falling edge T0 is fixed to be 200us +/-100 ns;
s3, obtaining detection echo gate delay: the integrated control and signal processing subsystem 4 generates a sampling wave gate under the trigger of a pulse-per-second falling edge T0, delays 199.75us to generate a marine detection emission pulse sampling wave gate, and the width of the marine detection emission pulse sampling wave gate is 500 ns;
calculating the ocean exploration echo wave gate time delay t1 according to the platform height h sent by the satellite platform in real time:
t1 ═ h-2250/0.15+200000, wherein the width of the sea detection echo gate is 30 us; calculating the atmospheric sounding wave gate delay t2 according to the platform height h:
t2 ═ h-30000/0.15+200000, wherein the width of the atmospheric sounding wave gate is 270 us;
s4, obtaining atmospheric optical parameter information and marine underwater topography information: the data acquisition processing unit 42 performs analog-to-digital conversion and cache on the ocean analog signal channel in the ocean detection emission pulse sampling wave gate and the ocean detection echo wave gate according to the sampling wave gate; the data acquisition processing unit 42 discriminates and counts photon pulses of the atmospheric photon signal channel in an atmospheric detection wave gate according to the sampling wave gate, frames the processed result and the state information of the high repetition frequency laser radar, and transmits the framed result and the state information of the high repetition frequency laser radar to a satellite platform for being transmitted to the ground for subsequent inversion processing, so as to obtain atmospheric optical parameter information and ocean underwater topography information.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (10)
1. A satellite-borne atmosphere ocean high repetition frequency laser radar system is characterized in that: the system comprises a high repetition frequency laser radar arranged on a satellite, wherein the high repetition frequency laser radar comprises a three-wavelength laser emission subsystem (1), an optical axis adjusting subsystem (2) electrically connected with the three-wavelength laser emission subsystem (1), a receiving optical subsystem (3) arranged on one side of the three-wavelength laser emission subsystem (1) and an integrated control and signal processing subsystem (4) which is electrically connected with the three-wavelength laser emission subsystem (1), the optical axis adjusting subsystem (2) and the receiving optical subsystem (3) and interacts with a satellite platform in a telemetering and remote control mode;
the three-wavelength laser emission subsystem (1) is used for emitting laser pulses with three wavelengths, splitting, expanding, combining and outputting the laser pulses into a beam of laser pulses and then outputting the laser pulses to the atmosphere, the seawater and the undersea target at a fixed angle, the optical axis adjusting subsystem (2) is used for adjusting the laser pulses after expanding, expanding and combining to point to the direction coaxial with the receiving optical subsystem (3), the receiving optical subsystem (3) is used for receiving the back scattering signals of the atmosphere, the seawater and the undersea target, splitting, color separation, narrow-band filtering and signal conditioning and converting the signals into analog signals to output the analog signals to the comprehensive control and signal processing subsystem (4), the comprehensive control and signal processing subsystem (4) is used for receiving driving instructions of the satellite platform and controlling the three-wavelength laser emission subsystem (1) to emit the laser pulses, and the comprehensive control and signal processing subsystem (4) is used for power supply, distribution and distribution of the high-repetition-frequency laser radar, And the comprehensive control and signal processing subsystem (4) is used for receiving the analog signals sent by the receiving optical subsystem (3), screening and framing the analog signals and sending the analog signals to the satellite platform.
2. A space-borne atmospheric marine high repetition rate lidar system according to claim 1, wherein: the three-wavelength laser emission subsystem (1) comprises a three-wavelength high-frequency laser (11), a light splitting and beam expanding adjusting module (12) arranged on one side of the three-wavelength high-frequency laser (11) and a laser controller (13) electrically connected with the three-wavelength high-frequency laser (11), wherein the laser controller (13) is electrically connected with the comprehensive control and signal processing subsystem (4);
the three-wavelength high-repetition-frequency laser (11) is used for emitting 355nm laser pulses, 532nm laser pulses and 1064nm laser pulses to the light splitting and beam expanding adjusting module (12), the light splitting and beam expanding adjusting module (12) is used for receiving the laser pulses emitted by the three-wavelength high-repetition-frequency laser (11), splitting the beams according to the wavelength, expanding the beams respectively, compressing the divergence angles of the laser, combining the beams into a beam of laser pulses and outputting the beam of laser pulses to the atmosphere, the seawater and the undersea target, and the laser controller (13) is used for generating pumping current pulses under the synchronous control of the comprehensive management unit (4) to drive the three-wavelength high-repetition-frequency laser (11) to emit the laser pulses.
3. The space-borne atmospheric marine high repetition frequency lidar system and the detection method according to claim 2, wherein: the pumping source of the three-wavelength high-repetition-frequency laser (11) is a Laser Diode (LD) for fiber coupling output, the end face pump Nd is a YAG laser medium, and a BBO electro-optical Q switch is inserted into the resonant cavity of the pumping source to construct a laser oscillation stage; the three-wavelength high-repetition-frequency laser (11) uses a laser diode end pump Nd, namely a YAG medium, which is output by fiber coupling, as a laser amplification stage, and the amplification stage adopts two-stage amplification; frequency multiplication is carried out on the 1064nm laser pulse output after two-stage amplification by using an LBO crystal to obtain the 532nm laser pulse output, and sum frequency of the two-stage amplified 1064nm laser pulse is used for obtaining the 355nm laser pulse output;
the beam splitting and expanding adjustment module (12) splits the 355nm, 532nm and 1064nm laser pulses into three beams using a high damage threshold dichroic mirror.
4. A space-borne atmospheric marine high repetition rate lidar system according to claim 1, wherein:
the optical axis adjusting subsystem (2) comprises an optical axis adjusting mechanism (21) arranged on one side of the three-wavelength laser emitting subsystem (1) and an optical axis adjusting driver (22) electrically connected with the optical axis adjusting mechanism (21);
the optical axis adjusting mechanism (21) is used for adjusting the laser pulse after beam expansion and combination to point to a direction coaxial with the receiving optical subsystem (3), and the optical axis adjusting driver (22) is used for driving and controlling the optical axis adjusting mechanism (21);
the receiving optical subsystem (3) comprises a receiving telescope (31) arranged on one side of the three-wavelength laser emission subsystem (1), a receiving optical unit (32) arranged on one side of the receiving telescope (31), a photoelectric detection unit (33) and a signal conditioning unit (34) which are sequentially and electrically connected with the optical unit (32);
the receiving telescope (31) is used for receiving the backscattering signals of the atmosphere, the seawater and the undersea target according to a time sequence and outputting the backscattering signals to the receiving optical unit (32), the receiving optical unit (32) is used for receiving the backscattering signals, splitting, color separation and narrow-band filtering are carried out on the backscattering signals, then the backscattering signals are respectively led into a 355nm vertical polarization channel, a 355nm parallel polarization channel, a 532nm vertical polarization channel and a 1064nm channel and output light signals to the photoelectric detection unit (33), the photoelectric detection unit (33) is used for detecting and receiving the light signals output by the receiving optical unit (32) and respectively converting the light signals into electric signals to be output to the signal conditioning unit (34), the signal conditioning unit (34) is used for receiving the electric signals sent by the photoelectric detection unit (33), carrying out multi-channel multi-stage amplification conditioning on the electric signals and converting the electric, each detection channel is branched into an atmospheric photon signal channel and an ocean analog signal channel after being conditioned.
5. A space-borne atmospheric marine high repetition rate lidar system according to claim 4, wherein: the receiving telescope (31) adopts a Cassegrain telescope structure, the caliber of the receiving telescope (31) is 500-1000 mm, and the laser pulse transmitted by the three-wavelength laser transmitting subsystem (1) and the receiving telescope (31) are coaxially output through a turning reflector;
the receiving optical unit (32) receives the backscattering signals of the atmosphere, the seawater and the undersea target by using a dichroic mirror, a polarizing beam splitter and a turning mirror subchannel, and the receiving optical unit (32) filters background light by using a narrow-band optical filter and an F-P standard distance combination mode;
said photodetector unit (33) detecting said optical signals of said 355nm vertically polarized channel, said 355nm parallel polarized channel, said 532nm parallel polarized channel, and said 532nm vertically polarized channel using a photomultiplier, said photodetector unit (33) detecting said optical signals of said 1064nm channel using a geiger-mode avalanche photodiode;
the signal conditioning unit (34) is used for conditioning the electric signals output by a single detector of the photoelectric detection unit (33) by adopting a multi-channel multi-stage amplification structure, and respectively carrying out conditioning on a bandwidth of 300MHz and a gain of 10dB to generate a first analog signal and conditioning on a bandwidth of 150MHz and a gain of 20dB to generate a second analog signal, wherein the first analog signal is used for photon counting detection, and the second analog signal is used for simulating echo detection.
6. A space-borne atmospheric marine high repetition rate lidar system according to claim 1, wherein: the integrated control and signal processing subsystem (4) comprises an integrated management unit (41) which is in telemetering and remote control interaction with the satellite platform and a data acquisition and processing unit (42) which is electrically connected with the receiving optical subsystem (3), and the integrated management unit (41) is electrically connected with the three-wavelength laser emission subsystem (1), the optical axis adjusting subsystem (2) and the receiving optical subsystem (3);
the integrated management unit (41) is used for receiving a driving instruction of the satellite platform and controlling the three-wavelength laser emission subsystem (1) to emit the laser pulse, and the integrated management unit (41) is used for power supply and distribution, time sequence and instruction control of the high repetition frequency laser radar; the data acquisition and processing unit (42) comprises a data processing unit, a high-speed comparator, an FPGA (field programmable gate array) and an analog-to-digital converter, the data processing unit is used for generating a sampling wave gate according to a sampling time sequence, the optical signals are screened and processed in the wave gate through the high-speed comparator and the FPGA, the analog-to-digital converter and the FPGA perform sampling processing on the analog signals, and the processed results are framed and sent to the satellite platform to be downloaded to the ground.
7. A space-borne atmospheric marine high repetition rate lidar system according to claim 6, wherein: the photon counting detection counting rate of the data acquisition processing unit (42) is greater than 50MCPS, the analog sampling rate of the data acquisition processing unit (42) is greater than 1GHz, and the effective digit of the data acquisition processing unit (42) is superior to 12 bits.
8. A space-borne atmospheric marine high repetition rate lidar system according to claim 1, wherein: the fixed angle is that laser pulse emission and intersatellite point keep 3 ~ 5.
9. A detection method of a satellite-borne atmospheric ocean high repetition frequency laser radar system is characterized by comprising the following steps: the method comprises the following steps:
s1, adjusting the optical axis: the optical axis adjusting driver (22) controls the optical axis adjusting mechanism (21) to direct the laser pulses output by the three-wavelength laser emission subsystem (1) to the direction coaxial with the receiving optical subsystem (3); emitting laser pulses to step S2, obtaining a detection echo gate delay to step S3, and performing step S2 and step S3 simultaneously;
s2, emitting laser pulses: the integrated control and signal processing subsystem (4) controls the three-wavelength high-repetition-frequency laser (11) to emit high-repetition-frequency laser pulses under the drive of a pulse-per-second falling edge provided by the satellite platform, wherein the pulse-per-second falling edge is T0 moment;
s3, obtaining detection echo gate delay: the integrated control and signal processing subsystem (4) generates a sampling wave gate under the trigger of the pulse per second falling edge T0, delays to generate a marine detection emission pulse sampling wave gate, and calculates the marine detection echo wave gate delay and the atmospheric detection wave gate delay according to the height of the satellite platform;
s4, obtaining atmospheric optical parameter information and marine underwater topography information: the data acquisition processing unit (42) performs analog-to-digital conversion and cache on an ocean analog signal channel in the ocean detection emission pulse sampling wave gate and the ocean detection echo wave gate according to the sampling wave gate; and the data acquisition processing unit (42) discriminates and counts photon pulses of the atmospheric photon signal channel in the atmospheric detection wave gate according to the sampling wave gate, frames the processed result and the state information of the high repetition frequency laser radar, and transmits the framed result and the state information of the high repetition frequency laser radar to the satellite platform to be transmitted to the ground for subsequent inversion processing, so as to obtain atmospheric optical parameter information and marine underwater topography information.
10. The method for detecting the spaceborne atmospheric marine high repetition frequency laser radar system according to claim 9, characterized in that:
in step S2, the emission frequency of the three-wavelength high-repetition laser (11) is 1 kHz; the time delay between the light emitting moment of the three-wavelength high-frequency and heavy-frequency laser (11) and the pulse-per-second falling edge T0 is fixed to be 200us +/-100 ns;
in step S3, delaying 199.75us to generate the ocean exploration transmission pulse sampling gate, wherein the width of the ocean exploration transmission pulse sampling gate is 500 ns;
in step S3, the ocean sounding echo gate delay t1 is calculated according to the platform height h sent by the satellite platform in real time:
t1 ═ h-2250)/0.15+200000, where the sea detection echo gate width is 30 us;
in step S3, the atmospheric sounding gate delay t2 is calculated according to the platform height h:
t2 ═ h-30000)/0.15+200000, where the atmospheric probe wave gate width is 270 us.
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| CN113126122A (en) * | 2021-04-02 | 2021-07-16 | 青岛海洋科学与技术国家实验室发展中心 | Interference imaging altimeter and laser radar double-satellite accompanying marine observation method and system |
| CN113126122B (en) * | 2021-04-02 | 2023-03-28 | 青岛海洋科学与技术国家实验室发展中心 | Interference imaging altimeter and laser radar double-satellite accompanying marine observation method and system |
| CN113514853A (en) * | 2021-04-07 | 2021-10-19 | 厦门大学 | Integrated laser detection method and integrated detection laser radar |
| CN113514853B (en) * | 2021-04-07 | 2023-12-08 | 厦门大学 | Integrated laser detection method and integrated detection laser radar |
| CN114235173A (en) * | 2021-11-17 | 2022-03-25 | 自然资源部第二海洋研究所 | Photon counting satellite-borne marine laser radar detection simulation method |
| CN114235173B (en) * | 2021-11-17 | 2024-04-09 | 自然资源部第二海洋研究所 | Photon counting satellite-borne ocean laser radar detection simulation method |
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