Flexible and configurable laser communication terminal test system and method

Abstract

The invention belongs to the technical field of laser communication, and particularly relates to a flexible and configurable laser communication terminal test system and method. The system comprises a calculation module used for controlling a test flow, checking a system state and a test result, and carrying out comparative analysis, statistical processing and local storage on test data; the clock module is used for internal and external clock switching and frequency multiplication output; the interface module is used for low-speed data communication, sending out an OC pulse signal at the same time, completing power-on, power-off and reset operation of the laser communication terminal, and providing dynamic and static 1PPS signals; the digital module is used for performing high-speed data processing, completing coding and modulation of a laser inter-satellite link signal transmission frame, and demodulation and decoding of a laser inter-satellite link signal information frame and a ranging frame, and sending the decoded data to the calculation module for subsequent analysis; and the optical module is used for providing a laser light source and completing mutual conversion between light and an electric signal and light emitting and receiving functions of multiple modulation modes.

Description

Technical Field

[0001] The invention belongs to the technical field of laser communication, and in particular relates to a flexible and configurable laser communication terminal testing system and method. Background Art

[0002] In order to meet the testing needs of various satellite laser communication services and to cover a wider range of laser communication equipment tests, the following three test configurations are usually adopted: from low bit rate to high bit rate, from incoherent to coherent systems, and testing tasks for laser communication terminals in different bands.

[0003] The above three test configurations, each rate, each band, and each system can be combined to form dozens of laser communication terminals of different technical systems. The functional performance and stability of satellite laser communication terminals must be verified before launch. If the terminals of each system are equipped with corresponding test systems, the development cost of the terminals will be greatly increased. Moreover, the test systems supporting the terminals of each system require testers to learn again, and such test systems cannot be used as calibration test equipment to verify the problems of the terminals themselves, which seriously limits the expansion of contemporary satellite Internet.

[0004] Therefore, it is very important to design a flexible and configurable laser communication terminal test system and method that can improve the versatility, multiplexing rate and reliability of the test system. Summary of the invention

[0005] The present invention aims to overcome the problems of system incompatibility, poor equipment versatility and poor reliability in the prior art in the satellite laser communication service test of the existing equipment, and provides a flexible and configurable laser communication terminal test system and method that can improve the versatility, multiplexing rate and reliability of the test system.

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

[0007] Flexible and configurable laser communication terminal test system, including:

[0008] The computing module is used to control the test process, view the system status and test results, and compare, analyze, statistically process and locally store the test data;

[0009] Clock module, used for internal and external clock switching and frequency multiplication output;

[0010] Interface module, used for low-speed data communication, sends out OC pulse signals at the same time, completes the power-off and reset operations of the laser communication terminal, and provides dynamic and static 1PPS signals;

[0011] The digital module is responsible for high-speed data processing, completing the encoding and modulation of the laser intersatellite link signal transmission frame, as well as the demodulation and decoding of the laser intersatellite link signal information frame and ranging frame, and sending the decoded data to the calculation module for subsequent analysis;

[0012] The optical module is used to provide a laser light source, complete the mutual conversion between optical and electrical signals, and the optical transmission and reception functions of various modulation modes.

[0013] Preferably, the computing 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 computing module is equipped with human-computer interaction software, and the human-computer interaction software communicates with the clock module, interface module, digital module and optical module via PCIE protocol; the computing module provides a keyboard, mouse and display interface.

[0015] Preferably, the clock module includes an FPGA chip, a clock switching switch and a frequency multiplication chip; the FPGA chip receives PCIE instruction data and J30J interface instruction data, and then controls the clock switching switch to switch between the external clock and the internal clock; wherein the internal clock is a high-stability clock of 10MHz, and the external clock is a clock source of any frequency; the model of the FPGA chip is XC7A200T;

[0016] The clock signal enters the frequency multiplication chip after being output; the frequency multiplication chip model is LMX2594, and supports an output frequency range of 10MHz-15GHz.

[0017] Preferably, the interface module includes an FPGA chip, a local crystal oscillator, a PHY chip, an RS422 interface chip, an RS232 interface chip, an LVDS interface chip, an LLC instruction circuit and a Flash module; the local crystal oscillator, the PHY chip, the RS422 interface chip, the RS232 interface chip, the LVDS interface chip, the LLC instruction circuit and the Flash module are all connected to the FPGA chip for communication; the FPGA chip model is XC7K325T; the local crystal oscillator provides a clock for the interface module to form a minimum system, so that the interface module works without an external clock; the FPGA chip receives control instructions and low-speed data through a PCIE interface, divides the data of the corresponding interface and sends it to the corresponding chip;

[0018] The PHY chip model is RTL8211CLGR; the CAN interface chip model is PCA82C250T; the RS422 interface chip and RS232 interface chip both use MAX3160 chip; the LVDS interface chip uses SN65LVDS32 chip; the LLC instruction circuit is used to continuously generate a level signal for a period of time to control the system's power on / off and reset.

[0019] Preferably, the digital module includes two FPGA chips, a coherent receiver, a laser transceiver integrated module and an AD / DA module; the two FPGA chips are FPGA_A and FPGA_B respectively; the FPGA_A chip is responsible for the modulation and demodulation of the laser signal data, and the FPGA_B chip is responsible for the interaction of the external module data; the FPGA_A chip and the FPGA_B chip are connected through high-speed serial GTH and SRIO interfaces for transmitting high-speed business data;

[0020] The AD / DA module includes 2 ADC chips and 2 DAC chips;

[0021] The coherent receiver and laser transceiver integrated module are used to complete coherent mixing and data clock recovery. The mixed and clock recovered signals are sampled by two ADC chips, and the sampled digital signals are processed inside FPGA_A.

[0022] Preferably, the optical module includes a main control chip, a bias control circuit, a polarization-maintaining optical modulator, an optical attenuation control circuit, a polarization-maintaining optical attenuator, a polarization-maintaining optical amplifier, a polarization-maintaining beam splitter and a polarization-maintaining optical filter;

[0023] In the transmission optical path, the laser signal light is connected to the signal light input interface, and the main control chip modulates the baseband signal onto the laser signal light to form a transmission optical signal. The transmission optical signal passes through the polarization-maintaining optical splitter to form two beams, one of which is used to control the operation of the modulator for the bias control circuit, and the other is used to monitor the optical power.

[0024] In order to simulate the relative motion and position relationship of satellites, the main control chip controls the polarization-maintaining optical attenuator through the optical attenuation control circuit to simulate the variation of the transmitted optical power with the satellite motion, and supports adjustable signal optical transmission power through multi-level optical attenuation cascade;

[0025] In the receiving optical path, polarization-maintaining optical attenuators and polarization-maintaining optical amplifiers are cascaded in multiple stages to ensure that the signal light receiving power is adjustable; after the signal light passes through the polarization-maintaining optical attenuator, it is connected to an optical filter to filter out and suppress the existing spontaneous radiation noise and out-of-band noise.

[0026] The present invention also provides a flexible and configurable laser communication terminal testing method comprising the following steps:

[0027] S1, Multi-system laser communication modulation

[0028] After the computing module directly acquires data or acquires data through a high-speed data interface, the digital module performs frame structuring, encoding and scrambling of the data according to the preset communication rate, and the generated analog electrical signal is transmitted to the optical module, which performs modulation mapping in the QPSK / BPSK / OOK format according to the preset modulation mode to form the transmitted light;

[0029] S2, multi-system laser communication demodulation

[0030] After receiving the laser signal, the laser communication terminal test system identifies the modulation format of the received signal and recovers the code element signal; the identified modulation format is divided into coherent processing and incoherent processing. The coherent processing includes carrier capture, ADC sampling, matched filtering, code element synchronization and carrier tracking, and the incoherent processing includes envelope detection, ADC sampling, bandpass filtering, low-pass filtering and sampling decision.

[0031] The recovered symbol signal is then decoded, descrambled, deframed and processed for ranging, and finally the user data and ranging information are extracted and sent to the computing module or to the satellite platform via a high-speed data interface.

[0032] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention proposes a flexible and configurable laser communication terminal test system suitable for various environments. The system is adapted to the test tasks of laser communication terminals ranging from low bit rate to high bit rate, from incoherent to coherent systems, and different bands. At the same time, the influence of the integration of various configurations on the system volume is considered, and an external interface is adopted for the low reuse rate module, thereby reducing the system size and weight while ensuring the system integration. Moreover, the same system is subjected to joint testing of terminals of various systems, which is also a test of the test equipment itself, thereby achieving the effect of improving the reuse rate and reliability of the test system; (2) The modules of the present invention communicate with each other at a high speed based on the PCIE bus, and the modules all adopt the CPCI architecture. Based on the CPCI industrial control chassis, various test tasks can be completed by combining different modules; the low-speed interface communication test can be completed by the computing module and the interface module, the high-speed interface communication test can be completed by the computing module, the clock module, and the digital module, and the high-speed laser communication test and the laser communication ranging test can be completed by the computing module, the clock module, the digital module, and the optical module; the main control chip of each module supports the program overload function, and a specific test process can be completed by combining different modules and programs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the architecture of the computing module in the present invention;

[0034] Figure 2A schematic diagram of the clock module in the present invention

[0035] Figure 3 A schematic diagram of the architecture of the interface module in the present invention;

[0036] Figure 4 A schematic diagram of the architecture of the digital module in the present invention;

[0037] Figure 5 A schematic diagram of an optical module in the present invention;

[0038] Figure 6 A flow chart of the multi-system laser communication modulation process in the present invention;

[0039] Figure 7 The present invention is a flowchart of the demodulation process of multi-system laser communication. DETAILED DESCRIPTION

[0040] 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.

[0041] The present invention provides a flexible and configurable laser communication terminal test system, comprising:

[0042] The computing module is used to control the test process, view the system status and test results, and compare, analyze, statistically process and locally store the test data;

[0043] The clock module has internal and external clock switching and frequency multiplication output. The internal clock is a 10Mhz high-stable clock, and the external clock is a clock source of any frequency. Through the parameter setting of the human-computer interaction software, 3 clocks can be output simultaneously, and the clock frequency is calculated according to the frequency multiplication parameter;

[0044] Interface module, which realizes low-speed data communication, such as CAN, RS422, RS232, LVDS and other interface communications, sends out OC pulse signals, completes the power-off and reset operations of the laser communication terminal, and provides dynamic and static 1PPS signals;

[0045] Digital module, which realizes high-speed data communication, such as laser communication, Tlk2711 communication, etc., completes the encoding and modulation of laser intersatellite link signal transmission frames, as well as the demodulation and decoding of laser intersatellite link signal information frames and ranging frames, and sends the decoded data to the calculation module for subsequent analysis;

[0046] The optical module provides a laser light source to achieve mutual conversion between optical and electrical signals, and completes the optical transmission and reception functions of various modulation modes such as QPSK, BPSK, OOK, etc. The optical module is equipped with an optical amplifier, optical attenuator, and optical filter on the transmission and reception links to ensure the quality of the input and output optical signals.

[0047] The above five modules are interconnected based on the CPCI architecture, and use the PCIE protocol as the basic communication protocol for data exchange, realizing flexible and configurable laser communication terminal test tasks for various systems.

[0048] Further, such as Figure 1 As shown, the computing 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. The computing module is equipped with human-computer interaction software, which communicates with the clock module, interface module, digital module and optical module through the PCIE protocol. The user can set the working parameters of other modules in the human-computer interaction interface; in addition, the computing module also provides a keyboard, mouse and display interface.

[0049] Further, such as Figure 2 As shown, the clock module includes an FPGA chip, a clock switching switch and a frequency multiplier chip; the FPGA chip of the clock module is XC7A200T, and the FPGA chip receives PCIE instruction data and J30J interface instruction data, and then controls the clock switching switch to switch between the external clock and the internal clock; the clock signal is output and enters the frequency multiplier chip, which is LMX2594 and supports an output frequency range of 10MHz-15GHz.

[0050] Further, such as Figure 3 As shown, the interface module includes an FPGA chip, a local crystal oscillator, a PHY chip, an RS422 interface chip, an RS232 interface chip, an LVDS interface chip, an LLC instruction circuit and a Flash module; the local crystal oscillator, the PHY chip, the RS422 interface chip, the RS232 interface chip, the LVDS interface chip, the LLC instruction circuit and the Flash module are all connected to the FPGA chip for communication;

[0051] The FPGA of the interface module uses XC7K325T, and the local crystal oscillator provides the clock to form a minimum system, which can work without an external clock. The FPGA receives control instructions and low-speed data through the PCIE interface, divides the data of the corresponding interface and sends it to the corresponding chip. Among them, the PHY chip uses RTL8211CLGR. The CAN interface chip uses PCA82C250T. The RS422 and RS232 interface chips use the MAX3160 chip, and the LVDS interface chip uses the SN65LVDS32 chip. The LLC instruction circuit is used to continuously generate a level signal for a period of time, which is used for equipment power on / off and reset.

[0052] Further, such as Figure 4 As shown, the digital module includes two FPGA chips, a coherent receiver, a laser transceiver module and an AD / DA module; the two FPGA chips are FPGA_A and FPGA_B; FPGA_A is responsible for the modulation and demodulation of laser signal data, and FPGA_B is responsible for the interaction of external module data; FPGA_B uses XC7K325T, and FPGA_A uses XC7VX690T. FPGA_A and FPGA_B are connected through high-speed serial GTH and SRIO interfaces to transmit high-speed business data

[0053] The AD / DA module includes 2 ADC chips and 2 DAC chips; the baseband data generated by FPGA_A is sent to the optical module through 2 high-speed DACs;

[0054] The coherent receiver and laser transceiver integrated module are used to complete coherent mixing and data clock recovery. The mixed and clock recovered signals are sampled by two ADC chips, and the sampled digital signals are processed inside FPGA_A.

[0055] Further, such as Figure 5As shown in the figure, the main components of the optical module transmission optical path include polarization-maintaining optical modulator (Mach-Zehnder modulator / MZ modulator), polarization-maintaining optical splitter, polarization-maintaining optical attenuator, etc. The laser signal light is connected to the signal light input interface, and the main control chip modulates the baseband signal onto the signal light to form a transmission optical signal. The transmission optical signal passes through the optical splitter to form two beams, one of which is used to control the operation of the modulator for the bias control circuit, and the other is used to monitor the optical power. In order to simulate the relative motion and position relationship of the satellite, the main control chip controls the optical attenuator through the optical attenuation control circuit to simulate the law of the change of the transmission optical power with the satellite motion, and supports the adjustable signal light transmission power through multi-stage optical attenuation cascade. The main components of the receiving optical path include polarization-maintaining optical attenuator, polarization-maintaining optical amplifier, polarization-maintaining optical splitter, polarization-maintaining optical filter, etc. The multi-stage cascade of polarization-maintaining optical attenuator and polarization-maintaining optical amplifier can meet the adjustable signal light receiving power. After the signal light passes through the optical attenuator, there is spontaneous radiation noise and out-of-band noise. An optical filter can be connected to filter and suppress the above noise to meet the signal quality requirements of coherent demodulation. The optical splitter is mainly used to split the received light, monitor the status of various received lights for remote measurement while meeting the optical link processing.

[0056] The main test task of the laser communication terminal test system is laser communication ranging. In order to complete the laser communication and ranging tasks of various systems and adapt to the functional modules of the CPCI architecture, a general high-speed laser communication ranging technology is designed, including multi-system laser communication modulation and multi-system laser communication demodulation technology.

[0057] Specifically, the present invention also provides a flexible and configurable laser communication terminal testing method comprising the following steps:

[0058] S1, Multi-system laser communication modulation

[0059] After the computing module directly obtains data or obtains data through a high-speed data interface, the digital module frames, encodes and scrambles the data according to the preset communication rate, and the generated analog electrical signal is transmitted to the optical module, which performs modulation mapping in the QPSK / BPSK / OOK format according to the preset modulation method to form an emission light; Figure 6 As shown, the specific process is as follows:

[0060] Step S11, the calculation module or the high-speed data interface module obtains user data and sends it to the digital module;

[0061] Step S12, the digital module selects corresponding interpolation and decimation coefficients according to the preset communication rate, and resamples the data; the resampled symbol data stream is framed at the set rate;

[0062] Step S13, when framing, a specific code group is inserted into the front of the code data stream, and the receiving end determines the start and end positions of the data frame by detecting the specific code group, thereby achieving data frame synchronization;

[0063] Step S14, when the assembly of the data frame is completed, the system fills the time difference information with the 1PPS rising edge time into the ranging frame, and integrates the data frame and the ranging frame into an inter-satellite transmission frame, and then performs coding and scrambling;

[0064] Step S15, during coding and scrambling, the inter-satellite transmission frame is encoded according to a preset coding method; after the coding is completed, in order to ensure the randomness of the data sequence in the communication and prevent the loss of synchronization information or the equalizer from not converging and causing performance degradation, the encoded data is scrambled; the generating polynomial used by the scrambling module is provided by the calculation module, and the scrambled data is subjected to signal modulation processing;

[0065] Step S16, signal modulation processing includes incoherent and coherent modulation modes; signal envelope modulation or frequency phase modulation is performed according to the modulation format set by the calculation module.

[0066] S2, multi-system laser communication demodulation

[0067] After receiving the laser signal, the laser communication terminal test system identifies the modulation format of the received signal and recovers the code element signal; the identified modulation format is divided into coherent processing and incoherent processing. The coherent processing includes carrier capture, ADC sampling, matched filtering, code element synchronization and carrier tracking, and the incoherent processing includes envelope detection, ADC sampling, bandpass filtering, low-pass filtering and sampling decision.

[0068] The recovered symbol signal is then decoded, descrambled, deframed and processed for ranging, and finally the user data and ranging information are extracted and sent to the calculation module or the data and ranging information are sent to the satellite platform through a high-speed data interface; Figure 7 As shown, the specific process is as follows:

[0069] Step S21, the laser communication terminal test system identifies the modulation format of the received optical signal and sets coherent demodulation parameters or incoherent demodulation parameters;

[0070] Step S22, if it is coherent demodulation, the optical signal is captured and calculated after the mixed data is sampled by the ADC, and the difference between the local oscillator optical frequency of the optical module and the signal optical frequency is determined according to the calculation result; the difference is fed back to the control chip of the optical module to adjust the local oscillator optical frequency; after the carrier is successfully captured, the signal is matched filtered;

[0071] Step S23, the calculation module sets the matching filter coefficient according to the signal rate and bandwidth, selects the useful signal, suppresses various noises and interferences, and performs symbol synchronization on the signal after matching filtering;

[0072] Step S24, during symbol synchronization, after each loop calculation determines the best sampling point of the input data stream, ranging calculation and carrier tracking calculation are performed on the sampled data;

[0073] Step S25, when calculating the distance, first record the 1PPS time when the symbol data is read; then, after the symbol data undergoes carrier tracking, frame synchronization, LDPC decoding and descrambling, and deframing processing, extract the time identification information, and perform inter-satellite pseudo-range measurement;

[0074] Step S26, during carrier tracking, after receiving the data after symbol synchronization, the slight frequency difference between the carriers of the transmitting and receiving ends will be processed; in order to eliminate the influence of carrier deviation on the communication performance of the system, the module further estimates and compensates the carrier frequency; after the carrier tracking process, the symbol will converge to 0 and 1, correcting the frequency deviation of the received signal; at this time, the data will be frame synchronized and decoded;

[0075] Step S27, frame synchronization determines the start and end positions of the frame by identifying the special code group inserted during the previous framing, and extracts the encoded data after the frame header for decoding and descrambling; after descrambling and decoding, the inter-satellite transmission frame is further deframed to generate user data frames and ranging frames; after ranging calculation, the ranging frame is sent to the calculation module for analysis; the user data frame is transmitted to the satellite platform through the high-speed interface module, or directly sent to the calculation module for analysis.

[0076] Step S28, if it is non-coherent demodulation, the data sampled by the ADC of the optical signal is used to detect the amplitude keying signal through an envelope detector to restore the baseband signal;

[0077] Step S29, in the system, the bandpass filter is used to suppress noise, and the sampling decision device improves the receiver performance, thereby effectively recovering the baseband signal; the recovered baseband signal will undergo frame synchronization, decoding and descrambling, deframing and ranging processing to extract user data and ranging information, and send it to the satellite platform for analysis through the high-speed data interface, or transmit it to the computing module for analysis.

[0078] The present invention proposes a flexible and configurable laser communication terminal test system suitable for various environments. The system is adapted to test tasks of laser communication terminals ranging from low bit rate to high bit rate, from incoherent to coherent systems, and different bands. Meanwhile, the influence of the integration of various configurations on the system volume is considered, and an external interface mode is adopted for low reuse rate modules, so that the system size and weight are reduced while ensuring the system integration. Moreover, the same system is jointly tested by terminals of various systems, which is also an inspection of the test equipment itself, so as to achieve the effect of improving the reuse rate and credibility of the test system. The modules of the present invention perform high-speed communication based on a PCIE bus, and the modules all adopt a CPCI architecture. Based on a CPCI industrial control chassis, various test tasks can be completed by combining different modules. The low-speed interface communication test can be completed by a calculation module and an interface module, the high-speed interface communication test can be completed by a calculation module, a clock module, and a digital module, and the high-speed laser communication test and the laser communication ranging test can be completed by a calculation module, a clock module, a digital module, and an optical module. The main control chip of each module supports a program overload function, and a specific test flow can be completed by combining different modules and programs.

[0079] 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. Flexible and configurable laser communication terminal test system, characterized by: include: The computing module is used to control the test process, view the system status and test results, and compare, analyze, statistically process and locally store the test data; Clock module, used for internal and external clock switching and frequency multiplication output; Interface module, used for low-speed data communication, sends out OC pulse signals at the same time, completes the power-off and reset operations of the laser communication terminal, and provides dynamic and static 1PPS signals; The digital module is responsible for high-speed data processing, completing the encoding and modulation of the laser intersatellite link signal transmission frame, as well as the demodulation and decoding of the laser intersatellite link signal information frame and ranging frame, and sending the decoded data to the calculation module for subsequent analysis; The optical module is used to provide a laser light source, complete the mutual conversion between optical and electrical signals, and the optical transmission and reception functions of various modulation modes.

2. The flexible and configurable laser communication terminal test system according to claim 1 is characterized in that: The computing module comprises a CPCI mainboard; an SSD solid state drive and a DDR3 memory are arranged on the CPCI mainboard; an external interface is also arranged on the CPCI mainboard; the external interface comprises a Gigabit Ethernet interface and a USB2.0 / 3.0 interface.

3. The flexible and configurable laser communication terminal test system according to claim 2 is characterized in that: The computing module is equipped with human-computer interaction software, and the human-computer interaction software communicates with the clock module, the interface module, the digital module and the optical module through the PCIE protocol; the computing module provides a keyboard, mouse and display interface.

4. The flexible and configurable laser communication terminal test system according to claim 1, characterized in that: The clock module includes an FPGA chip, a clock switching switch and a frequency multiplication chip; the FPGA chip receives PCIE instruction data and J30J interface instruction data, and then controls the clock switching switch to switch between the external clock and the internal clock; wherein the internal clock is a 10MHz high-stable clock, and the external clock is a clock source of any frequency; the model of the FPGA chip is XC7A200T; The clock signal enters the frequency multiplication chip after being output; the frequency multiplication chip model is LMX2594, and supports an output frequency range of 10MHz-15GHz.

5. The flexible and configurable laser communication terminal test system according to claim 1, characterized in that: The interface module includes an FPGA chip, a local crystal oscillator, a PHY chip, an RS422 interface chip, an RS232 interface chip, an LVDS interface chip, an LLC instruction circuit and a Flash module; the local crystal oscillator, the PHY chip, the RS422 interface chip, the RS232 interface chip, the LVDS interface chip, the LLC instruction circuit and the Flash module are all connected to the FPGA chip for communication; the FPGA chip model is XC7K325T; the local crystal oscillator provides a clock for the interface module to form a minimum system, so that the interface module works without an external clock; the FPGA chip receives control instructions and low-speed data through a PCIE interface, divides the data of the corresponding interface and sends it to the corresponding chip; The PHY chip model is RTL8211CLGR; the CAN interface chip model is PCA82C250T; the RS422 interface chip and RS232 interface chip both use MAX3160 chip; the LVDS interface chip uses SN65LVDS32 chip; the LLC instruction circuit is used to continuously generate a level signal for a period of time to control the system's power on / off and reset.

6. The flexible and configurable laser communication terminal test system according to claim 1, characterized in that: The digital module includes two FPGA chips, a coherent receiver, a laser transceiver integrated module and an AD / DA module; the two FPGA chips are FPGA_A and FPGA_B respectively; the FPGA_A chip is responsible for the modulation and demodulation of laser signal data, and the FPGA_B chip is responsible for the interaction of external module data; the FPGA_A chip and the FPGA_B chip are connected through high-speed serial GTH and SRIO interfaces for transmitting high-speed business data; The AD / DA module includes 2 ADC chips and 2 DAC chips; The coherent receiver and laser transceiver integrated module are used to complete coherent mixing and data clock recovery. The mixed and clock recovered signals are sampled by two ADC chips, and the sampled digital signals are processed inside FPGA_A.

7. The flexible and configurable laser communication terminal test system according to claim 1, characterized in that: The optical module includes a main control chip, a bias control circuit, a polarization-maintaining optical modulator, an optical attenuation control circuit, a polarization-maintaining optical attenuator, a polarization-maintaining optical amplifier, a polarization-maintaining optical splitter and a polarization-maintaining optical filter; In the transmission optical path, the laser signal light is connected to the signal light input interface, and the main control chip modulates the baseband signal onto the laser signal light to form a transmission optical signal. The transmission optical signal passes through the polarization-maintaining optical splitter to form two beams, one of which is used to control the operation of the modulator for the bias control circuit, and the other is used to monitor the optical power. In order to simulate the relative motion and position relationship of satellites, the main control chip controls the polarization-maintaining optical attenuator through the optical attenuation control circuit to simulate the variation of the transmitted optical power with the satellite motion, and supports adjustable signal optical transmission power through multi-level optical attenuation cascade; In the receiving optical path, polarization-maintaining optical attenuators and polarization-maintaining optical amplifiers are cascaded in multiple stages to ensure that the signal light receiving power is adjustable; after the signal light passes through the polarization-maintaining optical attenuator, it is connected to an optical filter to filter out and suppress the existing spontaneous radiation noise and out-of-band noise.

8. A flexible and configurable laser communication terminal test method, applied to a flexible and configurable laser communication terminal test system as claimed in any one of claims 1 to 7, characterized in that: The flexible and configurable laser communication terminal testing method comprises the following steps: S1, Multi-system laser communication modulation After the computing module directly acquires data or acquires data through a high-speed data interface, the digital module performs frame structuring, encoding and scrambling of the data according to the preset communication rate, and the generated analog electrical signal is transmitted to the optical module, which performs modulation mapping in the QPSK / BPSK / OOK format according to the preset modulation mode to form the transmitted light; S2, multi-system laser communication demodulation After receiving the laser signal, the laser communication terminal test system identifies the modulation format of the received signal and recovers the code element signal; the identified modulation format is divided into coherent processing and incoherent processing. The coherent processing includes carrier capture, ADC sampling, matched filtering, code element synchronization and carrier tracking, and the incoherent processing includes envelope detection, ADC sampling, bandpass filtering, low-pass filtering and sampling decision. The recovered symbol signal is then decoded, descrambled, deframed and processed for ranging, and finally the user data and ranging information are extracted and sent to the computing module or to the satellite platform via a high-speed data interface.

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