A communication satellite payload test system based on SDR platform

Abstract

A communication satellite payload test system based on an SDR platform comprises an SDR platform, an upconverter, a downconverter, a data generation module, a parameter configuration module, a signal processing module and a communication index calculation module; the data generation module generates original test digital signals; the original test digital signals are transmitted to a satellite payload to be tested along the signal processing module, the SDR platform and the upconverter, the satellite payload to be tested returns feedback signals; the feedback signals are sent to the communication index calculation module along the downconverter, the SDR platform and the signal processing module for communication index calculation. During the whole process, the parameter configuration module adaptively configures the communication parameters of the SDR platform based on the parameters of the satellite payload to be tested, and the signal processing module uniformly processes the received signals of different satellites, thereby realizing communication with satellites of different communication systems and test index calculation based on different received signals.

Description

Technical Field

[0001] This invention relates to a communication satellite payload testing system based on the SDR platform, belonging to the field of integrated testing of spacecraft payload subsystems. Background Technology

[0002] Communication satellite payload testing refers to the testing of various functional performance indicators of the payload during the satellite's ground development phase, such as EIRP, G / T, bit error rate, and packet loss rate, to ensure that all payload indicators meet user requirements. Satellite payload testing is conducted throughout the entire satellite ground development process and is the most effective means of ensuring satellite product quality, as well as a crucial step in ensuring the satellite provides normal service after launch and in orbit.

[0003] In recent years, communication satellites, represented by Internet communication satellites, high-throughput satellites, and relay satellites, have been fully equipped with various digital processing payloads. As a result, the performance indicators for payload testing have not only included radio frequency channel characteristics such as output power, but have also gradually included physical layer modulation and demodulation performance such as bit error rate and packet loss rate, as well as upper-layer system protocol items, which has placed higher demands on ground testing systems.

[0004] Because different satellites use different communication systems, the parameter characteristics of their transmitted and received signals vary significantly. Existing ground-based effective testing systems are all specialized designs for communication satellites in different application scenarios; that is, dedicated test equipment is designed for each satellite, each subsystem, and each payload. Therefore, existing ground-based effective testing systems cannot communicate with satellites using different communication systems, nor can they process signals with different parameter characteristics to calculate corresponding indicators, resulting in extremely low versatility. Using existing testing systems for payload testing not only wastes human and material resources but also results in long equipment development cycles and high development costs, failing to meet current testing requirements for cost-effectiveness, mass production, and parallel development. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of existing technologies and provide a communication satellite payload testing system based on the SDR platform. This system adaptively configures the communication parameters of the SDR platform based on the parameters of the payload of the satellite under test, and performs unified processing of received signals from different satellites through a signal processing module. This enables communication with satellites using different communication systems and the calculation of test indicators based on different received signals, thus solving the problems of low versatility and poor compatibility in existing systems.

[0006] The technical solution of this invention is: A communication satellite payload testing system based on an SDR platform includes: an SDR platform, an upconverter, a downconverter, a data generation module, a parameter configuration module, a signal processing module, and a communication performance calculation module. The SDR platform includes communication parameters; the parameter configuration module configures the communication parameters of the SDR platform based on the parameters of the satellite payload under test; the data generation module includes a general signal processing function library. The data generation module is used to generate the original test digital signal; The signal processing module preprocesses the original test digital signal based on the parameters of the satellite payload under test using a general signal processing function library to generate a test digital signal. The SDR platform performs analog-to-digital signal processing on the test digital signal based on communication parameters to generate a test analog baseband signal, which is then sent to the up-converter. The up-converter performs up-conversion processing on the test analog baseband signal to generate a test analog signal, which is then sent to the satellite payload under test. The satellite payload under test receives and processes the test analog signal, generates a feedback analog signal, and sends the feedback analog signal to the down-converter. The downconverter performs downconversion processing on the feedback analog signal to generate a feedback low-frequency analog signal; the SDR platform receives the feedback low-frequency analog signal based on communication parameters and performs analog-to-digital signal processing on the feedback low-frequency analog signal to generate a feedback low-frequency digital signal; the signal processing module performs post-processing on the feedback low-frequency digital signal based on the parameters of the satellite payload under test using a general signal processing function library to obtain the feedback digital signal. The communication index calculation module calculates the communication index of the satellite payload under test based on the original test digital signal and the feedback digital signal.

[0007] Furthermore, the communication parameters of the SDR platform include: transmit frequency, receive frequency, channel bandwidth, transmit gain, receive gain, and antenna channel.

[0008] Furthermore, the parameter configuration module configures the communication parameters of the SDR platform based on the parameters of the satellite payload under test, specifically as follows: The parameter configuration module configures the transmit and receive frequencies of the SDR platform based on the working center frequency of the satellite payload under test, combined with the local oscillator frequencies of the up-converter and down-converter. The parameter configuration module configures the channel bandwidth of the SDR platform according to the signal operating bandwidth of the satellite payload under test and the constraint that the bandwidth of the SDR platform must be greater than the operating bandwidth of the payload signal. The parameter configuration module calculates the power range of the SDR platform output signal based on the input power range of the satellite payload under test and the insertion loss result of the link transmission between the upconverter and the satellite payload under test, and configures the transmission gain of the SDR platform based on the power range of the output signal. The parameter configuration module calculates the power range of the signal received by the SDR platform based on the maximum output power of the satellite payload under test and the insertion loss result of the link transmission between the downconverter and the satellite payload under test, and configures the receiving gain of the SDR platform based on the power range of the received signal. The parameter configuration module obtains the antenna channel of the SDR platform based on the connection relationship between the satellite payload under test and the radio frequency link of the SDR platform.

[0009] Furthermore, the SDR platform performs analog-to-digital signal processing on the test digital signal based on communication parameters to generate a test analog baseband signal, and sends the test analog baseband signal to the up-converter. The specific process is as follows: The first step is that the SDR platform performs digital-to-analog signal processing on the test digital signal based on the channel bandwidth to generate a test analog baseband signal. The digital-to-analog signal processing operation specifically involves upsampling, data stream framing and packing, digital up-conversion, and digital-to-analog conversion on the test digital baseband signal in sequence. The second step involves the SDR platform sending a test analog baseband signal to the upconverter based on the transmit frequency point and transmit gain, according to the configured antenna channel.

[0010] Furthermore, the SDR platform receives the feedback low-frequency analog signal based on communication parameters, and performs analog-to-digital signal processing on the feedback low-frequency analog signal to generate the feedback low-frequency digital signal. The specific process is as follows: The first step is for the SDR platform to receive low-frequency analog signals based on the receiving frequency and receiving gain, according to the configured antenna channels. The second step involves the SDR platform performing analog-to-digital signal processing on the feedback low-frequency analog signal based on the channel bandwidth, generating a feedback low-frequency digital signal. Specifically, the SDR platform sequentially performs internal down-conversion, analog-to-digital conversion, digital down-conversion, and decimation filtering on the feedback low-frequency analog signal.

[0011] Furthermore, the general signal processing function library encapsulates basic signal processing functions adapted to various satellite systems; these basic signal processing functions include frame processing functions, quantization processing functions, CRC check functions, sampling functions, preamble synchronization functions, bit synchronization functions, disturbance processing functions, modulation and demodulation functions, encoding and decoding functions, frequency offset and phase compensation functions, channel equalization functions, and I / Q processing functions.

[0012] Furthermore, the specific process by which the signal processing module preprocesses the original test digital signal based on the parameters of the satellite payload under test using a general signal processing function library is as follows: The first step is for the signal processing module to determine the system type of the satellite payload based on the parameters of the satellite payload under test. In the second step, the signal processing module sequentially calls the frame processing function, CRC check function, disturbance processing function, encoding and decoding function, modulation and demodulation function, channel equalization function, and I / Q processing function in the general signal processing function library that correspond to the system type of the satellite payload under test. The original test digital signal is framed, CRC check code is added, scrambled, encoded, modulated, shaped and filtered, and I / Q data modulated, and finally the test digital signal is obtained.

[0013] Furthermore, the specific process by which the signal processing module performs post-processing on the low-frequency digital signals in the feedback, based on the parameters of the satellite payload under test and utilizing a general signal processing function library, is as follows: The first step is for the signal processing module to determine the system type of the satellite payload based on the parameters of the satellite payload under test. In the second step, the signal processing module sequentially calls the quantization processing function, sampling function, preamble synchronization function, bit synchronization function, frequency offset and phase compensation function, modulation and demodulation function, disturbance processing function, encoding and decoding function, and CRC check function in the general signal processing function library corresponding to the system type of the satellite payload under test. The module performs quantization, downsampling, preamble synchronization, bit synchronization, frequency offset and phase compensation, demodulation, descrambling, decoding, and CRC check on the low-frequency digital signal in the feedback, and finally obtains the feedback digital signal.

[0014] Furthermore, the specific process of receiving and processing the test simulation signal by the satellite payload under test is as follows: the satellite payload under test processes the test simulation signal according to the preprocessing procedure of its own input received signal under on-orbit working condition.

[0015] Furthermore, the communication metrics of the satellite payload under test include: bit error rate, packet loss rate, and output power.

[0016] The advantages of this invention compared to the prior art are: (1) The present invention adapts the communication parameters of the SDR platform based on the parameters of the satellite payload under test, and performs unified processing of the received signals of different satellites through the signal processing module, realizing communication with satellites with different communication systems and calculation of test indicators based on different received signals. It can be adapted to the payload test of various types of satellites, improving the versatility of the test system.

[0017] (2) The present invention uses a parameter configuration module to adaptively configure the communication parameters of the SDR platform based on the parameters of the satellite payload under test, thereby enabling the SDR platform to communicate with satellite payloads of various communication systems, realizing the unification of communication between different satellite payloads and the test system, and ensuring the universality of the test system.

[0018] (3) The data generation module of the present invention is equipped with a general signal processing function library. The general signal processing function library encapsulates basic signal processing functions adapted to various satellite systems. When a signal is received, the data generation module selects the appropriate processing function based on the communication satellite payload parameters to perform signal processing, thereby realizing the calculation of test indicators for different types of communication satellite payloads. Attached Figure Description

[0019] Figure 1 This is an overall block diagram of a communication satellite payload testing system based on an SDR platform according to the present invention. Figure 2 This is a schematic diagram illustrating the workflow of a communication satellite payload testing system based on an SDR platform according to the present invention. Figure 3 This invention relates to a preprocessing step for the signal processing module in a communication satellite payload testing system based on an SDR platform. Figure 4 This describes the post-processing steps of the signal processing module in a communication satellite payload testing system based on an SDR platform according to the present invention. Detailed Implementation

[0020] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0021] like Figure 1 As shown, the present invention provides a communication satellite payload testing system based on an SDR platform, including: an SDR platform, an upconverter, a downconverter, a data generation module, a parameter configuration module, a signal processing module, and a communication index calculation module; The SDR platform includes communication parameters; the parameter configuration module configures the communication parameters of the SDR platform based on the parameters of the satellite payload under test; the data generation module includes a general signal processing function library. The data generation module is used to generate the original test digital signal; The signal processing module preprocesses the original test digital signal based on the parameters of the satellite payload under test using a general signal processing function library to generate a test digital signal. The SDR platform performs analog-to-digital signal processing on the test digital signal based on communication parameters to generate a test analog baseband signal, which is then sent to the up-converter. The up-converter performs up-conversion processing on the test analog baseband signal to generate a test analog signal, which is then sent to the satellite payload under test. The satellite payload under test receives and processes the test analog signal, generates a feedback analog signal, and sends the feedback analog signal to the down-converter. The downconverter performs downconversion processing on the feedback analog signal to generate a feedback low-frequency analog signal; the SDR platform receives the feedback low-frequency analog signal based on communication parameters and performs analog-to-digital signal processing on the feedback low-frequency analog signal to generate a feedback low-frequency digital signal; the signal processing module performs post-processing on the feedback low-frequency digital signal based on the parameters of the satellite payload under test using a general signal processing function library to obtain the feedback digital signal. The communication performance index calculation module calculates the communication performance index of the satellite payload under test based on the original test digital signal and the feedback digital signal; the workflow of the entire system is as follows: Figure 2 As shown.

[0022] Furthermore, the SDR platform adopts a broadband universal RF front-end and a unified FPGA hardware architecture. The hardware is not customized or fixed for any particular satellite communication system, but rather adapted through software custom programming. The hardware is uniformly configured with consistent sampling clock, ADC / DAC sampling rate, RF operating frequency, and digital up / down conversion hardware channels, providing only a unified IQ digital baseband data input / output interface.

[0023] Furthermore, the data generation module, parameter configuration module, signal processing module, and communication index calculation module are all deployed on the industrial control computer; the industrial control computer and the SDR platform communicate via a switch.

[0024] Furthermore, the communication parameters of the SDR platform include: transmit frequency, receive frequency, channel bandwidth, transmit gain, receive gain, and antenna channel.

[0025] Furthermore, the parameter configuration module configures the communication parameters of the SDR platform based on the parameters of the satellite payload under test, specifically as follows: The parameter configuration module configures the transmit and receive frequencies of the SDR platform based on the working center frequency of the satellite payload under test, combined with the local oscillator frequencies of the up-converter and down-converter. The parameter configuration module configures the channel bandwidth of the SDR platform according to the signal operating bandwidth of the satellite payload under test and the constraint that the bandwidth of the SDR platform must be greater than the operating bandwidth of the payload signal. The parameter configuration module calculates the power range of the SDR platform output signal based on the input power range of the satellite payload under test and the insertion loss result of the link transmission between the upconverter and the satellite payload under test, and configures the transmission gain of the SDR platform based on the power range of the output signal. The parameter configuration module calculates the power range of the signal received by the SDR platform based on the maximum output power of the satellite payload under test and the insertion loss result of the link transmission between the downconverter and the satellite payload under test, and configures the receiving gain of the SDR platform based on the power range of the received signal. The parameter configuration module obtains the antenna channel of the SDR platform based on the connection relationship between the satellite payload under test and the radio frequency link of the SDR platform.

[0026] The host computer configures various hardware parameters of the SDR platform based on the operating parameters of the satellite payload under test: It configures the transmit and receive frequencies to ensure the test analog signal is aligned with the payload's uplink operating frequency and the receive local oscillator is aligned with the payload's downlink output frequency, guaranteeing that the feedback analog signal can be down-converted to baseband correctly; it configures the transmit gain to precisely control the output level of the test analog signal, meeting the requirements of linear interval testing while avoiding oversaturation of the satellite payload due to high-power signals; it configures the receive gain to reasonably amplify the feedback analog signal, balancing weak signal reception capability with preventing sampling overflow during analog-to-digital conversion; it configures the operating bandwidth to ensure the SDR platform's transmit and receive bandwidth is consistent with the payload channel bandwidth, limiting the signal spectrum and filtering out out-of-band interference to ensure the accuracy of in-band performance measurements; and it configures the antenna transmit and receive channels to ensure the SDR platform transmits the test analog signal and receives the feedback analog signal through the correct ports.

[0027] Furthermore, the SDR platform performs analog-to-digital signal processing on the test digital signal based on communication parameters to generate a test analog baseband signal, and sends the test analog baseband signal to the up-converter. The specific process is as follows: The first step is that the SDR platform performs digital-to-analog signal processing on the test digital signal based on the channel bandwidth to generate a test analog baseband signal. The digital-to-analog signal processing operation specifically involves upsampling, data stream framing and packing, digital up-conversion, and digital-to-analog conversion on the test digital baseband signal in sequence. The second step involves the SDR platform sending a test analog baseband signal to the upconverter based on the transmit frequency point and transmit gain, according to the configured antenna channel.

[0028] Furthermore, the SDR platform receives the feedback low-frequency analog signal based on communication parameters, and performs analog-to-digital signal processing on the feedback low-frequency analog signal to generate the feedback low-frequency digital signal. The specific process is as follows: The first step is for the SDR platform to receive low-frequency analog signals based on the receiving frequency and receiving gain, according to the configured antenna channels. The second step involves the SDR platform performing analog-to-digital signal processing on the feedback low-frequency analog signal based on the channel bandwidth, generating a feedback low-frequency digital signal. Specifically, the SDR platform sequentially performs internal down-conversion, analog-to-digital conversion, digital down-conversion, and decimation filtering on the feedback low-frequency analog signal.

[0029] This invention uses a parameter configuration module to adaptively configure the communication parameters of the SDR platform based on the parameters of the satellite payload under test. This enables the SDR platform to communicate with satellite payloads using various communication systems, achieving unification of communication between different satellite payloads and the test system and ensuring the versatility of the test system.

[0030] Furthermore, the general signal processing function library encapsulates basic signal processing functions adapted to various satellite systems; these basic signal processing functions include frame processing functions, quantization processing functions, CRC check functions, sampling functions, preamble synchronization functions, bit synchronization functions, disturbance processing functions, modulation and demodulation functions, encoding and decoding functions, frequency offset and phase compensation functions, channel equalization functions, and I / Q processing functions.

[0031] Furthermore, the specific process by which the signal processing module preprocesses the original test digital signal based on the parameters of the satellite payload under test using a general signal processing function library is as follows: The first step is for the signal processing module to determine the system type of the satellite payload based on the parameters of the satellite payload under test. The second step involves the signal processing module sequentially calling the frame processing function, CRC check function, scrambling function, encoding / decoding function, modulation / demodulation function, channel equalization function, and I / Q processing function from the general signal processing function library, corresponding to the system type of the satellite payload under test. These functions perform framing, CRC checksum addition, scrambling, encoding, modulation, shaping filtering, and I / Q data modulation on the original test digital signal, ultimately yielding the test digital signal, such as... Figure 3 As shown.

[0032] Furthermore, the specific process by which the signal processing module performs post-processing on the low-frequency digital signals in the feedback, based on the parameters of the satellite payload under test and utilizing a general signal processing function library, is as follows: The first step is for the signal processing module to determine the system type of the satellite payload based on the parameters of the satellite payload under test. The second step involves the signal processing module sequentially calling the quantization function, sampling function, preamble synchronization function, bit synchronization function, frequency offset and phase compensation function, modulation and demodulation function, disturbance handling function, encoding and decoding function, and CRC check function from the general signal processing function library, corresponding to the system type of the satellite payload under test. This process performs quantization, downsampling, preamble synchronization, bit synchronization, frequency offset and phase compensation, demodulation, descrambling, decoding, and CRC check on the low-frequency digital signal in the feedback, ultimately obtaining the feedback digital signal, such as... Figure 4 As shown.

[0033] Furthermore, the basic signal processing functions in the general signal processing function library corresponding to the system type of the satellite payload under test are as follows: Define the system type of the satellite payload under test as the target type, and define the basic signal processing function in the general signal processing function library that corresponds to the system type of the satellite payload under test as the target function; if there is a basic signal processing function in the general signal processing function library that is the same as the target type of the satellite, then use that basic signal processing function as the target function; otherwise, use the basic signal processing function in the signal processing function library that is closest to the target type of the satellite.

[0034] Furthermore, based on parameters such as satellite communication frequency, orbital parameters, frequency division multiplexing scheme, communication bandwidth, and communication protocol, it can be determined whether the satellite system types are similar.

[0035] The data generation module of this invention is equipped with a general signal processing function library. The general signal processing function library encapsulates basic signal processing functions that are compatible with various satellite systems. When a signal is received, the data generation module selects the appropriate processing function based on the communication satellite payload parameters to perform signal processing, thereby realizing the calculation of test indicators for different types of communication satellite payloads.

[0036] Furthermore, the satellite's system type includes transparent forwarding single-carrier system, broadband multi-carrier system, FDMA system, and TDMA system.

[0037] Furthermore, the specific process of receiving and processing the test simulation signal by the satellite payload under test is as follows: the satellite payload under test processes the test simulation signal according to the preprocessing procedure of its own input received signal under on-orbit working condition.

[0038] Furthermore, the communication metrics of the satellite payload under test include: bit error rate, packet loss rate, and output power.

[0039] The communication index calculation module calculates the bit error rate as follows: After performing phase synchronization and demodulation decoding on the feedback digital signal, the communication index calculation module compares the bit sequences of the original test digital signal and the feedback digital signal bit by bit, and counts the total number of erroneous bits and the total number of transmitted bits. The ratio of the two is the bit error rate result. The packet loss rate is calculated as follows: the communication index calculation module counts the total number of data packets formed by the original test digital signal within a preset time and the total number of data packets formed by the feedback digital signal within a preset time. The ratio of the two is the packet loss rate. The packet error rate is calculated as follows: The communication index calculation module performs phase synchronization and demodulation decoding on all feedback digital signals received within a preset time, restoring each feedback digital signal to the corresponding received bit sequence; the communication index calculation module performs CRC check on all received bit sequences, and the ratio of the number of received bit sequences that fail the CRC check to the total number of received bit sequences is the packet error rate. The specific calculation of output power is as follows: The communication index calculation module performs IQ sampling and channel filtering on the feedback digital signal in sequence, counts the instantaneous power of all sampling points within the bandwidth and performs time averaging, and corrects it by combining it with the RF link loss obtained by pre-calibration to obtain the output power.

[0040] Based on the above design, this invention adaptively configures the communication parameters of the SDR platform based on the parameters of the satellite payload under test, and performs unified processing of the received signals from different satellites through the signal processing module. This enables communication with satellites with different communication systems and the calculation of test indicators based on different received signals. It can be adapted to the payload testing of various types of satellites, thus improving the versatility of the testing system.

[0041] The parts of this invention not described in detail are common knowledge to those skilled in the art.

Claims

1. A communication satellite payload testing system based on an SDR platform, characterized in that, include: SDR platform, up-converter, down-converter, data generation module, parameter configuration module, signal processing module, and communication index calculation module; The SDR platform includes communication parameters; the parameter configuration module configures the communication parameters of the SDR platform based on the parameters of the satellite payload under test; the data generation module includes a general signal processing function library. The data generation module is used to generate the original test digital signal; The signal processing module preprocesses the original test digital signal based on the parameters of the satellite payload under test using a general signal processing function library to generate a test digital signal. The SDR platform performs analog-to-digital signal processing on the test digital signal based on communication parameters to generate a test analog baseband signal, which is then sent to the up-converter. The up-converter performs up-conversion processing on the test analog baseband signal to generate a test analog signal, which is then sent to the satellite payload under test. The satellite payload under test receives and processes the test analog signal, generates a feedback analog signal, and sends the feedback analog signal to the down-converter. The downconverter performs downconversion processing on the feedback analog signal to generate a feedback low-frequency analog signal; the SDR platform receives the feedback low-frequency analog signal based on communication parameters and performs analog-to-digital signal processing on the feedback low-frequency analog signal to generate a feedback low-frequency digital signal; the signal processing module performs post-processing on the feedback low-frequency digital signal based on the parameters of the satellite payload under test using a general signal processing function library to obtain the feedback digital signal. The communication index calculation module calculates the communication index of the satellite payload under test based on the original test digital signal and the feedback digital signal.

2. The communication satellite payload testing system based on the SDR platform according to claim 1, characterized in that: The communication parameters of the SDR platform include: transmit frequency, receive frequency, channel bandwidth, transmit gain, receive gain, and antenna channel.

3. The communication satellite payload testing system based on the SDR platform according to claim 2, characterized in that: The parameter configuration module configures the communication parameters of the SDR platform based on the parameters of the satellite payload under test, specifically as follows: The parameter configuration module configures the transmit and receive frequencies of the SDR platform based on the working center frequency of the satellite payload under test, combined with the local oscillator frequencies of the up-converter and down-converter. The parameter configuration module configures the channel bandwidth of the SDR platform according to the signal operating bandwidth of the satellite payload under test and the constraint that the bandwidth of the SDR platform must be greater than the operating bandwidth of the payload signal. The parameter configuration module calculates the power range of the SDR platform output signal based on the input power range of the satellite payload under test and the insertion loss result of the link transmission between the upconverter and the satellite payload under test, and configures the transmission gain of the SDR platform based on the power range of the output signal. The parameter configuration module calculates the power range of the signal received by the SDR platform based on the maximum output power of the satellite payload under test and the insertion loss result of the link transmission between the downconverter and the satellite payload under test, and configures the receiving gain of the SDR platform based on the power range of the received signal. The parameter configuration module obtains the antenna channel of the SDR platform based on the connection relationship between the satellite payload under test and the radio frequency link of the SDR platform.

4. The communication satellite payload testing system based on the SDR platform according to claim 2, characterized in that: The SDR platform performs analog-to-digital signal processing on the test digital signal based on communication parameters, generates a test analog baseband signal, and sends the test analog baseband signal to the up-converter. The specific process is as follows: The first step is that the SDR platform performs digital-to-analog signal processing on the test digital signal based on the channel bandwidth to generate a test analog baseband signal. The digital-to-analog signal processing operation specifically involves upsampling, data stream framing and packing, digital up-conversion, and digital-to-analog conversion on the test digital baseband signal in sequence. The second step involves the SDR platform sending a test analog baseband signal to the upconverter based on the transmit frequency point and transmit gain, according to the configured antenna channel.

5. A communication satellite payload testing system based on an SDR platform according to claim 2, characterized in that: The SDR platform receives low-frequency analog signals from the feedback based on communication parameters, and performs analog-to-digital signal processing on the feedback low-frequency analog signals to generate low-frequency digital signals. The specific process is as follows: The first step is for the SDR platform to receive low-frequency analog signals based on the receiving frequency and receiving gain, according to the configured antenna channels. The second step involves the SDR platform performing analog-to-digital signal processing on the feedback low-frequency analog signal based on the channel bandwidth, generating a feedback low-frequency digital signal. Specifically, the SDR platform sequentially performs internal down-conversion, analog-to-digital conversion, digital down-conversion, and decimation filtering on the feedback low-frequency analog signal.

6. The communication satellite payload testing system based on the SDR platform according to claim 1, characterized in that: The general signal processing function library encapsulates basic signal processing functions adapted to various satellite systems; these basic signal processing functions include frame processing functions, quantization processing functions, CRC check functions, sampling functions, preamble synchronization functions, bit synchronization functions, disturbance processing functions, modulation and demodulation functions, encoding and decoding functions, frequency offset and phase compensation functions, channel equalization functions, and I / Q processing functions.

7. A communication satellite payload testing system based on an SDR platform according to claim 6, characterized in that: The specific process by which the signal processing module preprocesses the original test digital signal based on the parameters of the satellite payload under test using a general signal processing function library is as follows: The first step is for the signal processing module to determine the system type of the satellite payload based on the parameters of the satellite payload under test. In the second step, the signal processing module sequentially calls the frame processing function, CRC check function, disturbance processing function, encoding and decoding function, modulation and demodulation function, channel equalization function, and I / Q processing function in the general signal processing function library that correspond to the system type of the satellite payload under test. The original test digital signal is framed, CRC check code is added, scrambled, encoded, modulated, shaped and filtered, and I / Q data modulated, and finally the test digital signal is obtained.

8. A communication satellite payload testing system based on an SDR platform according to claim 6, characterized in that: The specific process by which the signal processing module performs post-processing on the low-frequency digital signals in the feedback, based on the parameters of the satellite payload under test and utilizing a general signal processing function library, is as follows: The first step is for the signal processing module to determine the system type of the satellite payload based on the parameters of the satellite payload under test. In the second step, the signal processing module sequentially calls the quantization processing function, sampling function, preamble synchronization function, bit synchronization function, frequency offset and phase compensation function, modulation and demodulation function, disturbance processing function, encoding and decoding function, and CRC check function in the general signal processing function library corresponding to the system type of the satellite payload under test. The module performs quantization, downsampling, preamble synchronization, bit synchronization, frequency offset and phase compensation, demodulation, descrambling, decoding, and CRC check on the low-frequency digital signal in the feedback, and finally obtains the feedback digital signal.

9. A communication satellite payload testing system based on an SDR platform according to any one of claims 1 to 8, characterized in that: The specific process by which the satellite payload under test receives and processes the test simulation signal is as follows: the satellite payload under test processes the test simulation signal according to the preprocessing procedure of its own input received signal under on-orbit working condition.

10. A communication satellite payload testing system based on an SDR platform according to claims 1-8, characterized in that: The communication metrics of the satellite payload under test include: bit error rate, packet loss rate, and output power.

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