Satellite-borne laser terminal simulation test equipment and method for multiple rate systems

Abstract

The invention belongs to the technical field of laser communication, and particularly relates to a satellite-borne laser terminal simulation test device and method for multiple rate systems. The equipment comprises a CPU main control module which is used for being responsible for the overall control of a system and the collection and processing of test data; the clock module is used for providing multi-channel clock signal output and ensuring the synchronization of the system at different rates; the digital interface module is used for low-speed data communication, supports various interfaces and carries out data processing through an FPGA (Field Programmable Gate Array) chip; the digital processing module is used for performing high-speed data processing, performing signal modulation and demodulation, and realizing complex digital signal processing through an FPGA chip; and the optical front-end module is used for transmitting and receiving laser signals and simulating Doppler frequency offset and signal attenuation. The device has the advantages that the universality and flexibility of the device are remarkably improved, the test requirements of laser terminals of different models can be met, and the development and maintenance cost of the device is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of laser communication, and in particular relates to satellite-borne laser terminal simulation test equipment and methods for multiple rate systems. Background Art

[0002] With the rapid development of satellite laser communication technology, the onboard laser terminal must be verified for functional integrity before the satellite is launched. Since different models of onboard laser terminals have different laser rates and wavelengths, ground test equipment needs to be flexibly adapted to these terminals. Existing laser communication ground simulation equipment is usually designed for a specific model of laser terminal, and the test equipment can only meet the test requirements of that model. If special test equipment is designed for each model, it will not only increase the development cost, but also greatly increase the difficulty of equipment maintenance and operation.

[0003] Existing test equipment usually lacks modular design and configuration flexibility when dealing with the needs of laser communication at multiple rates. Therefore, in the test process of multi-rate and multi-system laser terminals, there are problems such as low test efficiency, poor equipment versatility, and difficulty in covering the diverse needs of different terminals.

[0004] Therefore, it is very important to design a ground simulation device that can adapt to different types of satellite-borne laser terminals and multiple rate systems. Summary of the invention

[0005] The present invention aims to overcome the problems of rate system incompatibility and poor equipment versatility in the prior art of existing equipment in ground testing of laser communication terminals. It provides a satellite-borne laser terminal simulation test equipment and method for multiple rate systems that adopts a modular design and realizes multi-system laser communication terminal testing by dividing the test requirements into different functional modules of ground simulation equipment.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] Spaceborne laser terminal simulation test equipment for various rate systems, including:

[0008] CPU main control module is responsible for overall system control and test data collection and processing;

[0009] Clock module, used to provide multiple clock signal outputs to ensure system synchronization at different rates;

[0010] Digital interface module, used for low-speed data communication, supports multiple interfaces, and performs data processing through FPGA chip;

[0011] Digital processing module, responsible for high-speed data processing, signal modulation and demodulation, and realizing complex digital signal processing through FPGA chip;

[0012] Optical front-end module, used for transmitting and receiving laser signals, and simulating Doppler frequency shift and signal attenuation.

[0013] Preferably, the CPU main control module includes a CPCI mainboard; the CPCI mainboard is provided with an SSD solid state drive and a DDR3 memory; the CPCI mainboard is also provided with an external interface; the external interface includes a Gigabit Ethernet interface and a USB2.0 / 3.0 interface.

[0014] Preferably, the CPU main control module also includes a keyboard, mouse and display device for providing a UI interface; the UI interface is used to enable the user to perform human-computer interaction and complete corresponding operations.

[0015] Preferably, a dip switch is provided in the clock module; the dip switch is used to realize the internal and external clock switching function; when the dip switch is turned to 0, it is the internal clock; when the dip switch is turned to 1, it is the external clock; wherein, the internal clock is a high-stable clock of 10MHz, and the external clock is a clock source of any frequency.

[0016] Preferably, the digital interface module communicates with the CPU main control module through the Ethernet port; the digital interface module includes an FPGA management module, a 422 communication interface module, an LVDS interface module, an Ethernet control module and a Flash module; the 422 communication interface module, the LVDS interface module, the Ethernet control module and the Flash module are all communicatively connected with the FPGA management module; the digital interface module manages the 1PPS synchronization signal and realizes telemetry and remote control communication through the FPGA management module.

[0017] Preferably, the digital processing module includes two FPGA processing modules, an optical signal coherent receiving module and an AD / DA module; the two FPGA modules are respectively an FPGA_0 module and an FPGA_1 module;

[0018] The FPGA_0 module uses the internal hard core of the FPGA to realize the communication between the PCIE interface and the CPU main control module, and is used to transmit data core control information; the FPGA_0 module completes the timing control of the high-speed interface with the satellite platform through the high-speed interface chip; the FPGA_0 module is connected to the FPGA_1 module through the SRIO interface to realize the dynamic loading of the program of the FPGA_1 module;

[0019] The FPGA_1 module is used to complete complex signal processing functions, including signal modulation, demodulation and encoding and decoding;

[0020] The AD / DA module is used for analog-to-digital / digital-to-analog conversion of signal modulation and demodulation;

[0021] The optical signal coherent receiving module is electrically connected to the AD / DA module.

[0022] Preferably, the optical front-end module includes a bias controller, a modulator, an optical attenuator, a splitter, an optical amplifier and an optical filter;

[0023] The optical splitter splits the signal light to the bias controller for controlling the operation of the modulator;

[0024] The optical attenuator is used to prevent the onboard laser terminal from being damaged due to excessive optical power between the system and the onboard laser terminal;

[0025] The optical amplifier is used to make the input power of the back-end demodulation reach a set threshold;

[0026] The optical filter is used to filter out noise and balance gain of the amplified signal light.

[0027] The present invention also provides a satellite-borne laser terminal simulation test method for multiple rate systems, comprising the following steps:

[0028] S1, Multi-rate laser communication modulation

[0029] The test data is transmitted from the CPU main control module to the digital processing module through the PCIE bus; the digital processing module resamples the data according to the preset communication rate and adjusts the data rate through interpolation and extraction technology;

[0030] The data stream is framed and scrambled at a set rate, and the encoded data is converted from electrical signals to optical signals through an optical front-end module and transmitted to the onboard laser terminal;

[0031] S2, multi-system laser communication demodulation

[0032] The optical signal received by the test system is first processed by the optical front-end module. After the optical signal is converted into an electrical signal, it is converted to digital by the ADC in the AD / DA module. The system then identifies the modulation format of the electrical signal according to the preset communication protocol and selects coherent or incoherent processing based on the identification result. The coherent processing process includes carrier capture, matched filtering, symbol synchronization, carrier tracking and frame synchronization, followed by decoding, descrambling and deframing.

[0033] S3, Doppler frequency shift simulation

[0034] The user software calculates the range delay and Doppler frequency deviation information to be simulated based on the relevant parameters of intersatellite motion; the relevant parameters include satellite relative position, velocity vector, signal frequency, propagation delay, observation angle, timestamp and orbit parameters;

[0035] The calculated analog information is transmitted as control information to the optical front-end module, which performs frequency offset compensation and signal attenuation control to ensure that the signal adjustment meets expectations;

[0036] The simulated laser signal is split by a beam splitter to monitor the status of the optical signal in real time.

[0037] Compared with the prior art, the present invention has the following beneficial effects: (1) The laser communication ground simulation equipment of the present invention adopts the CPCI architecture and realizes the support for laser communication tasks of multiple rates and multiple systems and interface link test tasks through modular design; the equipment covers multi-rate universal high-speed laser communication technology, including modulation technology and demodulation technology of multi-rate laser communication, and realizes comprehensive coverage of test requirements under different communication rates, and can meet the test requirements of various satellite-borne laser terminals; (2) The present invention significantly improves the versatility and flexibility of the equipment, can meet the test requirements of different models of laser terminals, reduces the equipment development and maintenance costs, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the architecture of the CPU main control module in the present invention;

[0039] Figure 2 A schematic diagram of the architecture of the digital interface module in the present invention;

[0040] Figure 3 A schematic diagram of the architecture of the digital processing module in the present invention;

[0041] Figure 4 A schematic diagram of the signal flow of the optical front-end module in the present invention. DETAILED DESCRIPTION

[0042] In order to more clearly illustrate the embodiments of the present invention, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings and other implementation methods can be obtained based on these accompanying drawings without creative work.

[0043] The present invention provides a satellite-borne laser terminal simulation test device for multiple rate systems, comprising:

[0044] CPU main control module is responsible for overall system control and test data collection and processing;

[0045] Clock module, used to provide multiple clock signal outputs to ensure system synchronization at different rates;

[0046] Digital interface module, used for low-speed data communication, supports multiple interfaces (422, LVDS, Ethernet, etc.), and performs data processing through FPGA chip;

[0047] Digital processing module, responsible for high-speed data processing, signal modulation and demodulation, and realizing complex digital signal processing through FPGA chip;

[0048] The optical front-end module is used to transmit and receive laser signals and simulate Doppler frequency deviation and signal attenuation to ensure the signal quality of the laser link.

[0049] Through the flexible combination of the above modules, the present invention can realize laser communication modulation and demodulation under multiple systems, and is suitable for various rates and test tasks of satellite-borne laser terminals.

[0050] Further, such as Figure 1 As shown, the CPU main control module is a traditional CPCI motherboard, with the computer CPU as the core chip, equipped with a large-capacity, high-performance SSD solid-state drive and high-performance DDR3 memory. The external interface supports Gigabit Ethernet interface and USB2.0 / 3.0 interface, and supports external large-capacity USB storage devices to expand the device capacity. Provides keyboard, mouse and display device and UI interface, users can perform human-computer interaction and complete the operation of this system. The main function is to complete the configuration and detection of the entire system, including the status detection of the entire system, the sending and receiving and display of telemetry and remote control commands, the real-time reception of link test data and the comparison of the disk, and can also realize the sending and receiving of local data sources to complete the link performance test.

[0051] Furthermore, the clock module is provided with a dip switch; the dip switch is used to realize the internal and external clock switching function; when the dip switch is turned to 0, it is the internal clock; when the dip switch is turned to 1, it is the external clock; wherein, the internal clock is a 10MHz high-stability clock, and the external clock is a clock source of any frequency. Through the setting, the clock module can output three clock signals at the same time to meet the synchronization requirements of multi-rate laser communication.

[0052] Further, such as Figure 2As shown, the digital interface module adopts a design architecture based on FPGA as the main processing to realize low-speed data communication. It is mainly composed of FPGA management module, 422 communication interface module, LVDS interface module, Ethernet control module and Flash module. It mainly completes the management of 1PPS, telemetry and remote control communication function based on 422 interface, measurement and control communication function and communication of low-speed interfaces such as CAN bus, and communicates with the CPU main control module through the Ethernet port.

[0053] Further, such as Figure 3 As shown, the digital processing module includes two FPGA processing modules, an optical signal coherent receiving module and an AD / DA module; the two FPGA modules are FPGA_0 module and FPGA_1 module respectively;

[0054] FPGA_0 module uses the internal hard core of FPGA to realize the communication between PCIE interface and CPU main control module, which is used to transmit data core control information; it completes the timing control of the high-speed interface with the satellite platform through the high-speed interface chip; it connects with FPGA_1 module through SRIO interface to realize dynamic loading of program to FPGA_1 module;

[0055] The FPGA_1 module is used to complete complex signal processing functions, including signal modulation, demodulation and encoding and decoding;

[0056] The AD / DA module is used for analog-to-digital / digital-to-analog conversion of signal modulation and demodulation; wherein the DAC performs digital-to-analog conversion on the signal after BPSK mapping to obtain the output of the baseband modulation signal, and sends it to the laser modulator to obtain the laser modulation signal; the demodulation end converts the input laser modulation signal to the baseband through the laser local oscillator to obtain the I, Q baseband complex signal, and then performs ADC sampling;

[0057] The optical signal coherent receiving module is electrically connected to the AD / DA module.

[0058] Further, such as Figure 4 As shown, the optical front-end module includes a bias controller, a modulator, an optical attenuator, an optical splitter, an optical amplifier and an optical filter;

[0059] The optical splitter splits the signal light to the bias controller for controlling the operation of the modulator;

[0060] The optical attenuator is used to prevent the onboard laser terminal from being damaged due to excessive optical power between the system and the onboard laser terminal;

[0061] The optical amplifier is used to make the input power of the back-end demodulation reach a set threshold;

[0062] The optical filter is used to filter out noise and balance gain of the amplified signal light.

[0063] The optical front-end module needs to complete the functions of transmitting BPSK optical signals and receiving optical signals, as well as the function of detecting the optical transmission and reception status. To ensure the stable operation of the modulator, the optical front-end module needs a splitter to split the signal light to the bias controller for controlling the operation of the modulator. The optical attenuator is to prevent damage to the satellite laser terminal due to excessive optical power between this system and the satellite laser terminal. In order to monitor the optical power of the transmitted signal, a splitter detector is configured in front of the modulated light output port to detect the transmission power. The optical amplifier is to make the input power of the back-end demodulation reach a certain threshold. After the signal light passes through the optical amplifier, there is spontaneous radiation noise in the amplification process, and an optical filter needs to be configured to filter out the noise and balance the gain. The splitter is used to divide the received signal light into two equal parts, which is convenient for real-time monitoring of the status of the received optical signal. The main functions of the transmitting and receiving links are as follows:

[0064] 1. Modulation and conversion of electrical signals to optical signals. The DA unit on the digital processing board connects the coded and mapped electrical signals to the optoelectronic front-end module through cables. The modulation driver on the optoelectronic front-end module amplifies the electrical signals and inputs them into the modulator to modulate them into optical signals. After attenuation by the optical attenuator, the optical signals that meet the user's setting requirements are sent to the communication terminal under test. After the received optical signals are processed by EDFA and optical filter, they are input into the coherent receiver of the digital processing version.

[0065] 2. Perform Doppler frequency deviation and attenuation control on the transmitted optical signal. The user software calculates the required simulated distance delay, Doppler frequency deviation, amplitude attenuation and other information based on the intersatellite motion, and transmits the required control information through the digital processing module. The optoelectronic front end completes the main part of the Doppler frequency deviation and attenuation simulation. Since the Doppler frequency deviation of intersatellite communication is large, it is necessary to compensate the frequency deviation of the received optical signal.

[0066] Specifically, the present invention also provides a satellite-borne laser terminal simulation test method for multiple rate systems, comprising the following steps:

[0067] S1, Multi-rate laser communication modulation

[0068] The test data is transmitted from the CPU main control module to the digital processing module through the PCIE bus; the digital processing module resamples the data according to the preset communication rate and adjusts the data rate through interpolation and extraction technology;

[0069] The data stream is framed and scrambled at a set rate. The encoded data is converted from electrical signals to optical signals through the optical front-end module and transmitted to the onboard laser terminal. The entire modulation process is divided into the following detailed steps:

[0070] Step S11: Obtain test data

[0071] The CPU main control module or high-speed data interface module first obtains the user's test data, and then transmits the data to the digital processing module to prepare for subsequent modulation.

[0072] Step S12: Data resampling

[0073] The digital processing module selects appropriate interpolation and decimation coefficients according to the preset communication rate and resamples the data. The resampled symbol data stream is adjusted according to the communication rate to meet the laser communication requirements of different rate systems.

[0074] Step S13: Framing and scrambling

[0075] During the framing process, the symbol data stream is framed according to the preset protocol. Specific code groups are inserted at specific positions in the frame so that the receiving end can achieve frame synchronization. In addition, in order to improve the randomness of the data and avoid the loss of symbol synchronization, the data stream is scrambled. The scrambling uses a preset generating polynomial to ensure that there are not too many 0s or 1s in the data sequence, which can avoid system performance degradation.

[0076] Step S14: Data encoding

[0077] The encoding is performed according to the laser communication protocol. After being scrambled, the data stream is encoded according to the preset encoding method to improve the reliability and efficiency of communication. The encoded data is ready for modulation.

[0078] Step S15: Signal modulation

[0079] On the optical front-end module, the modulation driver amplifies the electrical signal and inputs it into the modulator for modulation to generate the corresponding optical signal. The optical signal is mapped according to the selected modulation method (such as QPSK, BPSK, etc.) and output to the onboard laser terminal for transmission.

[0080] S2, multi-system laser communication demodulation

[0081] The optical signal received by the test system is first processed by the optical front-end module. After the optical signal is converted into an electrical signal, it is converted to digital by the ADC in the AD / DA module. The system then identifies the modulation format of the electrical signal according to the preset communication protocol and selects coherent or incoherent processing based on the identification result. The coherent processing process includes carrier capture, matched filtering, symbol synchronization, carrier tracking and frame synchronization, followed by decoding, descrambling and deframing. The specific demodulation process includes the following detailed steps:

[0082] Step S21: Optical signal reception and modulation format identification

[0083] The system first receives the optical signal from the satellite-borne laser terminal and converts it into an electrical signal through the optical front-end module. After the signal is sampled by the ADC, the system identifies the modulation format and selects coherent or incoherent processing based on the modulation mode.

[0084] Step S22: Carrier capture and matched filtering

[0085] If it is coherent demodulation, after the signal is sampled by the ADC, the carrier capture calculation is performed first. The system determines the difference between the local oscillator optical frequency and the signal optical frequency based on the capture result. The local oscillator optical frequency is adjusted by the control chip to complete the carrier capture. After successful capture, the signal is matched filtered to select useful signals and suppress noise and interference.

[0086] Step S23: Symbol synchronization

[0087] The signal after matched filtering enters the symbol synchronization loop. The system determines the best sampling point of the input data stream through loop calculation, thereby improving the accuracy of demodulation and synchronization performance. Symbol synchronization ensures that subsequent data can be processed in the correct timing.

[0088] Step S24: Carrier tracking and frequency offset compensation

[0089] After symbol synchronization, the system performs carrier tracking processing to further estimate and compensate for the slight frequency difference between the receiving end and the transmitting end. Carrier tracking can correct the frequency deviation in the received signal, ensure that the demodulated signal is restored to symbol 0 or 1, and maintain the stability of the communication system.

[0090] Step S25: Frame synchronization and decoding

[0091] Frame synchronization determines the start and end of each data frame in the data stream by identifying the special code group agreed upon by the protocol in the data frame, thereby extracting the data in the data frame according to the agreed protocol, and then descrambling and decoding the data to obtain valid data.

[0092] Step S26: Data storage and transmission

[0093] The valid data is transmitted to the CPU main control module for test data storage, statistics and comparison.

[0094] S3, Doppler frequency shift simulation

[0095] Step S31: The user software calculates the range delay and Doppler frequency deviation information to be simulated according to the relevant parameters of intersatellite motion; the relevant parameters include satellite relative position, velocity vector, signal frequency, propagation delay, observation angle, timestamp and orbital parameters (satellite orbit type (such as circular, elliptical) and its related orbital elements);

[0096] Step S32: The calculated analog information is transmitted as control information to the optical front-end module, and the optical front-end module performs frequency offset compensation and signal attenuation control to ensure that the signal adjustment meets expectations;

[0097] Step S33: The simulated laser signal is split by a beam splitter to monitor the state of the optical signal in real time.

[0098] During the entire testing process, the CPU main control module is responsible for managing and scheduling various functional modules to ensure that all parts of the system work according to the predetermined process.

[0099] The CPU main control module collects and processes test data in real time, and communicates with other modules at high speed through the PCIE bus to ensure seamless data transmission.

[0100] The CPU main control module can also communicate with the satellite platform through a high-speed interface to support remote data monitoring and processing, ensuring the flexibility and efficiency of the entire test system.

[0101] Aiming at the test requirements of satellite-borne laser terminals of various systems, the laser communication ground simulation equipment of the present invention adopts CPCI architecture and realizes the support of laser communication tasks of various rates and systems and interface link test tasks through modular design. The equipment covers multi-rate universal high-speed laser communication technology, including modulation technology and demodulation technology of multi-rate laser communication, and realizes comprehensive coverage of test requirements under different communication rates, and can meet the test requirements of various satellite-borne laser terminals.

[0102] The present invention provides a ground simulation device for satellite-borne laser communication terminals applicable to various rate systems through modular design, PCIE bus data interaction, flexible clock configuration and Doppler frequency deviation control. Its design significantly improves the versatility and flexibility of the device, can meet the testing requirements of laser terminals of different models, reduces the cost of equipment development and maintenance, and has broad application prospects.

[0103] The above description is only a detailed description of the preferred embodiments and principles of the present invention. For ordinary technicians in this field, according to the ideas provided by the present invention, there will be changes in the specific implementation methods, and these changes should also be regarded as the protection scope of the present invention.

Claims

1. A satellite-borne laser terminal simulation test device for multiple rate systems, characterized in that: include: CPU main control module is responsible for overall system control and test data collection and processing; Clock module, used to provide multiple clock signal outputs to ensure system synchronization at different rates; Digital interface module, used for low-speed data communication, supports multiple interfaces, and performs data processing through FPGA chip; Digital processing module, responsible for high-speed data processing, signal modulation and demodulation, and digital signal processing through FPGA chip; Optical front-end module, used for transmitting and receiving laser signals, and simulating Doppler frequency shift and signal attenuation.

2. The satellite-borne laser terminal simulation test equipment for multiple rate systems according to claim 1 is characterized in that: The CPU main control module includes a CPCI mainboard; the CPCI mainboard is provided with an SSD solid state hard disk and a DDR3 memory; the CPCI mainboard is also provided with an external interface; the external interface includes a Gigabit Ethernet interface and a USB2.0 / 3.0 interface.

3. The satellite-borne laser terminal simulation test equipment for multiple rate systems according to claim 2 is characterized in that: The CPU main control module also includes a keyboard, mouse and display device for providing a UI interface; the UI interface is used to enable the user to perform human-computer interaction and complete corresponding operations.

4. The satellite-borne laser terminal simulation test equipment for multiple rate systems according to claim 1 is characterized in that: The clock module is provided with a dip switch; the dip switch is used to realize the internal and external clock switching function; when the dip switch is turned to 0, it is the internal clock; when the dip switch is turned to 1, it is the external clock; wherein, the internal clock is a high-stability clock of 10MHz, and the external clock is a clock source of any frequency.

5. The satellite-borne laser terminal simulation test equipment for multiple rate systems according to claim 1 is characterized in that: The digital interface module communicates with the CPU main control module through the Ethernet port; the digital interface module includes an FPGA management module, a 422 communication interface module, an LVDS interface module, an Ethernet control module and a Flash module; the 422 communication interface module, the LVDS interface module, the Ethernet control module and the Flash module are all communicatively connected with the FPGA management module; the digital interface module manages the 1PPS synchronization signal and realizes telemetry and remote control communication through the FPGA management module.

6. The satellite-borne laser terminal simulation test equipment for multiple rate systems according to claim 1, characterized in that: The digital processing module includes two FPGA processing modules, an optical signal coherent receiving module and an AD / DA module; the two FPGA modules are respectively an FPGA_0 module and an FPGA_1 module; The FPGA_0 module uses the internal hard core of the FPGA to realize the communication between the PCIE interface and the CPU main control module, and is used to transmit data core control information; the FPGA_0 module completes the timing control of the high-speed interface with the satellite platform through the high-speed interface chip; the FPGA_0 module is connected to the FPGA_1 module through the SRIO interface to realize the dynamic loading of the program of the FPGA_1 module; The FPGA_1 module is used to complete complex signal processing functions, including signal modulation, demodulation and encoding and decoding; The AD / DA module is used for analog-to-digital / digital-to-analog conversion of signal modulation and demodulation; The optical signal coherent receiving module is electrically connected to the AD / DA module.

7. The satellite-borne laser terminal simulation test equipment for multiple rate systems according to claim 1 is characterized in that: The optical front-end module includes a bias controller, a modulator, an optical attenuator, an optical splitter, an optical amplifier and an optical filter; The optical splitter splits the signal light to the bias controller for controlling the operation of the modulator; The optical attenuator is used to prevent the onboard laser terminal from being damaged due to excessive optical power between the system and the onboard laser terminal; The optical amplifier is used to make the input power of the back-end demodulation reach a set threshold; The optical filter is used to filter out noise and balance gain of the amplified signal light.

8. A satellite-borne laser terminal simulation test method for multiple rate systems, applied to a satellite-borne laser terminal simulation test device for multiple rate systems as claimed in any one of claims 1 to 7, characterized in that: The onboard laser terminal simulation test method for multiple rate systems comprises the following steps: S1, Multi-rate laser communication modulation The test data is transmitted from the CPU main control module to the digital processing module through the PCIE bus; the digital processing module resamples the data according to the preset communication rate and adjusts the data rate through interpolation and extraction technology; The data stream is framed and scrambled at a set rate, and the encoded data is converted from electrical signals to optical signals through an optical front-end module and transmitted to the onboard laser terminal; S2, multi-system laser communication demodulation The optical signal received by the test system is first processed by the optical front-end module. After the optical signal is converted into an electrical signal, it is converted into an analog-to-digital signal by the ADC in the AD / DA module. The system then identifies the modulation format of the electrical signal according to the preset communication protocol and selects coherent or incoherent processing mode based on the identification result. The coherent processing includes carrier acquisition, matched filtering, symbol synchronization, carrier tracking and frame synchronization, followed by decoding, descrambling and deframing. S3, Doppler frequency shift simulation The user software calculates the range delay and Doppler frequency deviation information to be simulated based on the relevant parameters of intersatellite motion; the relevant parameters include satellite relative position, velocity vector, signal frequency, propagation delay, observation angle, timestamp and orbit parameters; The calculated analog information is transmitted as control information to the optical front-end module, which performs frequency offset compensation and signal attenuation control to ensure that the signal adjustment meets expectations; The simulated laser signal is split by a beam splitter to monitor the status of the optical signal in real time.

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