Uplink and downlink closed-loop test method and system for spread spectrum data transmission broadcast of remote sensing satellite

Abstract

The invention discloses a remote sensing satellite spread spectrum data transmission broadcast uplink and downlink closed-loop test method and system. The method comprises the following steps: generating an instruction sequence for operating on-board equipment; generating content data required by the uplink data; according to a satellite uplink data protocol, jointly packaging an instruction sequence for operating on-board equipment and content data required by uplink data into an uplink baseband data block; processing the uplink baseband data block into a radio frequency signal, and sending the radio frequency signal to a satellite data transmission broadcast uplink receiving device; the satellite data transmission broadcast uplink receiving equipment re-analyzes the radio frequency signal into baseband data, executes the baseband data according to an instruction in the baseband data, stores and forwards or directly forwards required content data, and processes the required content data into the radio frequency signal; the satellite data transmission broadcast downlink sending device sends the radio frequency signal to the ground; re-analyzing the radio frequency signal into baseband data, performing analysis and extraction, and re-extracting content data; and comparing the required content data in the uplink data with the content data extracted and analyzed in the downlink to obtain a content correctness test report.

Description

Technical Field

[0001] The present invention relates to an on - satellite test system applicable to spread - spectrum frequency - multiplexed data transmission and broadcast of remote - sensing satellites, belonging to the field of on - satellite testing of remote - sensing satellites Background Technique

[0002] The data transmission subsystem is one of the important subsystems of remote - sensing satellites. The main function of the data transmission subsystem is to perform baseband processing, radio - frequency modulation, and power amplification on the original observation data from satellite payloads, and then transmit them outward through the data transmission antenna. Traditional data transmission subsystems generally transmit all data transmission data to ground stations or relay satellites, with relatively high requirements for data transmission rates and no special requirements for signal transmission systems. Therefore, traditional data transmission generally uses ordinary radio - frequency modulation without further processing of the radio - frequency spectrum. Currently, due to the increase in the types of users of remote - sensing satellites, the demand for the use of data transmission links has changed. It is not only necessary to transmit all data transmission data to ground stations but also to transmit specific parts of data transmission data between users. This has led to the addition of a spread - spectrum frequency - multiplexed data transmission and broadcast system to the on - satellite data transmission subsystem, which has the functions of data up - and - downlink and is specifically used for transmitting specific parts of data transmission data between users. During ground testing, it is necessary to verify the up - and - downlink functions of this spread - spectrum system data transmission and broadcast. Currently, the existing data transmission test systems only support demodulating data transmission signals with ordinary modulation methods and do not have the ability to demodulate spread - spectrum system data transmission signals. At the same time, the current test systems only support one - way, that is, only support sending signals upward to the satellite or receiving downward data signals from the satellite, and do not have the ability to verify the up - and - downlink closed - loop. Without re - developing the test system, it is impossible to conduct closed - loop test verification of the up - and - downlink of spread - spectrum frequency - multiplexed data transmission and broadcast. Therefore, designing a new integrated on - satellite test system is a new topic Summary of the Invention

[0003] The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, providing a method and system for closed - loop testing of the up - and - downlink of spread - spectrum frequency - multiplexed data transmission and broadcast applicable to remote - sensing satellites, and realizing the closed - loop verification of the up - and - downlink signals of spread - spectrum frequency - multiplexed data transmission and broadcast during satellite ground testing

[0004] The technical solution adopted by the present invention for solving the problem is: A method for closed - loop testing of the up - and - downlink of spread - spectrum frequency - multiplexed data transmission and broadcast of remote - sensing satellites, including:

[0005] On the ground, according to the satellite uplink data format protocol, satellite command format definition, and the usage method of data transmission and broadcast up - and - downlink, generate an instruction sequence for operating the satellite data transmission and broadcast uplink receiving device, satellite data storage device, and satellite data transmission and broadcast downlink receiving device; at the same time, according to user requirements, generate the content data required for uplink data

[0006] According to the satellite uplink data protocol, encapsulate the instruction sequence for operating the satellite data transmission and broadcast uplink receiving device, data storage device, and data transmission and broadcast downlink receiving device together with the content data required for uplink data into an uplink baseband data block

[0007] After processing the uplink baseband data block into a radio frequency signal according to the satellite uplink data protocol, it is sent to the satellite data transmission and broadcast uplink receiving device;

[0008] The satellite data transmission and broadcast uplink receiving device re - parses the radio frequency signal into baseband data, executes according to the instructions in the baseband data, stores and forwards or directly forwards the required content data through the satellite data transmission storage device and the data transmission and broadcast downlink sending device, and processes it into a radio frequency signal;

[0009] The satellite data transmission and broadcast downlink sending device sends the radio frequency signal to the ground;

[0010] Re - parse the radio frequency signal into baseband data, parse and extract the baseband data, and re - extract the content data; compare the required content data in the uplink data with the content data extracted and parsed from the downlink to obtain a content correctness test report.

[0011] Preferably, the uplink instruction format includes a packet main header, a sub - header, and an application data area;

[0012] The main header includes bytes for characterizing packet identification, bytes for characterizing packet sequence control, and a packet length byte; the sub - header includes bytes for characterizing the CCSDS sub - header flag, the PUS telecommand packet version number, the byte for correct command response, and the byte for service type and source address; the application data area includes the number of bus instructions, data, and check bytes for this upload.

[0013] Preferably, the uplink data format includes a synchronization header, a VCDU main header, a VCDU insertion area, a VCDU data unit, and a VCDU error control field; the VCDU data unit includes a BPDU header and a BPDU bit - stream data area, and the uplink instruction sequence is filled into the BPDU bit - stream data area.

[0014] Preferably, during the process of encapsulating into an uplink baseband data block, invalid data or idle frames are added before each uplink instruction. When the on - satellite device receives the invalid data or idle frames, it will enter a waiting state without performing operations, thus reserving a response time for the on - satellite device. The on - satellite devices include the satellite data transmission and broadcast uplink receiving device, the satellite data transmission storage device, and the satellite data transmission and broadcast downlink receiving device.

[0015] Preferably, the calculation method for the data volume of the invalid data or idle frames to be added is as follows:

[0016] According to the shortest response time or the shortest processing duration T1 of the on - satellite device and the data transmission rate v1, calculate T1 * v1 to obtain the data volume S1 of the idle frames to be filled.

[0017] A closed-loop ground test system for the up and down links of spread-spectrum frequency-division data transmission broadcasting of a remote sensing satellite, comprising a data generation module, a data encapsulation and transmission module, a signal transmission module, a signal reception module, a data extraction module, and a data comparison module;

[0018] The data generation module generates an instruction sequence for operating the satellite data transmission broadcasting uplink receiving device, the satellite data storage device, and the satellite data transmission broadcasting downlink receiving device according to the satellite uplink data format protocol, the satellite instruction format definition, and the usage method of the data transmission broadcasting up and down links; meanwhile, according to user requirements, it generates the content data required for the uplink data;

[0019] The data encapsulation and transmission module encapsulates the instruction sequence for operating the satellite data transmission broadcasting uplink receiving device, the data storage device, and the data transmission broadcasting downlink receiving device and the content data required for the uplink data into an uplink baseband data block according to the satellite uplink data protocol;

[0020] The signal transmission module processes the uplink baseband data block into a radio frequency signal according to the satellite uplink data protocol and sends it to the satellite data transmission broadcasting uplink receiving device;

[0021] The signal reception module re-parses the radio frequency signal sent from the on-board device to the ground into baseband data, and the data extraction module parses and extracts the baseband data to re-extract the content data;

[0022] The data comparison module compares the content data required in the uplink data with the content data extracted and parsed from the downlink to obtain a content correctness test report.

[0023] Preferably, the signal transmission module includes a spread-spectrum modulator and an upconverter;

[0024] The generated baseband signal is encoded, scrambled, modulated, and spread-spectrum by the spread-spectrum modulator to generate an intermediate-frequency signal containing the information of the baseband data block. After adjusting the intermediate-frequency signal to an appropriate size, it is input into the upconverter. The upconverter converts the intermediate-frequency signal to the radio frequency band and adjusts the radio frequency signal to an appropriate size before sending it to the satellite data transmission uplink receiving device;

[0025] The signal reception module includes a downconverter and a despread demodulator; the downconverter converts the radio frequency signal to the intermediate frequency, adjusts the intermediate-frequency signal to an appropriate size and then inputs it into the despread demodulator to despread, demodulate, descramble, and decode the intermediate-frequency signal to re-parse the content data contained in the baseband data.

[0026] Preferably, according to the signal size and the actual functions of the devices, an attenuator and a power amplifier are added.

[0027] Preferably, the uplink data format includes a synchronization header, a VCDU leading header, a VCDU insertion area, a VCDU data unit, and a VCDU error control field; the VCDU data unit includes a BPDU leading header and a BPDU bitstream data area, and the uplink instruction sequence is filled into the BPDU bitstream data area.

[0028] Preferably, during the process of encapsulating into uplink baseband data blocks, invalid data or idle frames are added before each uplink instruction. When the on-board device receives the invalid data or idle frames, it will enter a waiting state without performing operations, thus reserving response time for the on-board device. The on-board devices include satellite data transmission and broadcast uplink receiving devices, satellite data transmission and storage devices, and satellite data transmission and broadcast downlink receiving devices.

[0029] The beneficial effects of the present invention compared with the prior art are as follows:

[0030] The present invention provides a method for generating uplink signals for spread-spectrum data transmission of remote sensing satellites, a method for processing downlink signals, and provides a fully automatic closed-loop comparison and verification method for uplink and downlink data, which can improve the efficiency and reliability of the test of the data transmission subsystem of remote sensing satellites.

[0031] Advantage 1: In previous tests, instructions and data were sent separately. It was necessary to first send the satellite device power-on instruction, then send the data, then send the data reception instruction and data downlink instruction, and finally send the satellite device shutdown instruction. The number of operations was large and the time was long. The present invention encapsulates instructions and data into data blocks for transmission at the same time, enabling the satellite to automatically execute all instructions, thereby automatically turning on the device, receiving data, downlinking data, and shutting down the device in sequence. No other operations are required during the process, and the degree of automation is high, saving time.

[0032] Advantage 2: When the satellite uses the uplink channel, the ordinary instruction uplink channel and the spread-spectrum data transmission and broadcast uplink channel are two completely different channels for the satellite, and it is necessary to switch the ground transmission device. Since the uplink data must be transmitted through the spread-spectrum data transmission and broadcast uplink, when sending uplink data before, it was necessary to first switch to the ordinary instruction uplink device to send instructions, then switch to the spread-spectrum data transmission and broadcast uplink device to send data, and then switch to the ordinary instruction uplink device to send instructions. The process was complex. The present invention enables both instructions and data to be input into the satellite through the data transmission and broadcast uplink channel. There is no need to switch between the ordinary instruction uplink channel and the spread-spectrum data transmission and broadcast uplink channel during the operation process, and all operations can be completed using the same set of ground equipment, making it more convenient to use.

[0033] Advantage 3: In the prior art, manual comparison is required after receiving the downlink data. The present invention uses a signal reception module and a data comparison module, which can extract the data to be compared in real time and perform the comparison, reducing the comparison time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1It is the flowchart of the steps of the closed-loop test method for the up-link and down-link of the spread-spectrum data transmission broadcast of the remote sensing satellite of the present invention;

[0035] Figure 2 It is the principle block diagram of the closed-loop test system for the up-link and down-link of the spread-spectrum data transmission broadcast of the remote sensing satellite of the present invention. Specific embodiments

[0036] The present invention will be further described below in conjunction with embodiments.

[0037] The present invention discloses a closed-loop test method for the up-link and down-link of the spread-spectrum data transmission broadcast of a remote sensing satellite, which can be mainly applied to a remote sensing satellite with the functions of data transmission broadcast up-link and down-link, and during ground testing, verify the functions and links of the data transmission broadcast up-link and down-link.

[0038] The closed-loop test method for the up-link and down-link of the spread-spectrum data transmission broadcast of the remote sensing satellite includes:

[0039] Step 101, the data generation module generates uplink injection data.

[0040] The uplink injection data can be determined and input by the user according to actual mission requirements. At the same time, it is necessary to refer to the satellite uplink data format protocol, satellite command format definition, and the usage method of data transmission broadcast up-link and down-link to generate a complete data file with an uplink command format that operates on the satellite uplink data transmission broadcast uplink receiving device, satellite data transmission storage device, and satellite data transmission broadcast downlink receiving device. At the same time, according to the user's needs, the content data required for the uplink data is generated and stored in the storage area.

[0041] The following table is an example of an uplink command format

[0042]

[0043]

[0044] Step 102, the data encapsulation and sending module encapsulates the uplink injection data.

[0045] According to the satellite uplink data protocol, the instruction sequences for operating the satellite data transmission broadcast uplink receiving device, data transmission storage device, and data transmission broadcast downlink receiving device and the content data required for the uplink data are jointly encapsulated into an uplink baseband data block according to the usage logic.

[0046] The following table is an example of an uplink data format, and the uplink command is directly filled into the BPDU bit stream data area

[0047]

[0048] Since on-board devices require response time, it is necessary to add invalid data or idle frames for filling before each execution instruction. When the on-board device receives invalid data or idle frames, it will enter a waiting state without performing operations, thus reserving response time for the on-board device.

[0049] According to the shortest response time T1 and data transmission rate v1 of the on-board device, calculate T1 * v1 to obtain the data volume S1 of the idle frames that need to be filled.

[0050] When general satellite instructions are made into a sequence for uplink, in order to leave sufficient response time or data processing time for the device, it is necessary to set an interval for each instruction in the form of a time interval when making the instruction sequence. For example, Instruction 1 - Interval 1s - Instruction 2. After being sent to the satellite through the ordinary instruction uplink channel, the satellite will automatically parse the interval time, thus realizing the sequential sending of instructions. Since the instructions of the present invention are encapsulated into data blocks and uploaded through the data transmission and broadcast uplink channel, devices that cannot automatically parse the interval time by the satellite when using this channel cannot set the time interval in the data block. Therefore, the present invention proposes to insert idle frames between instructions. For example, Instruction 1 - Idle Frame - Instruction 2. The idle frame will occupy the channel rate during uplink, but the satellite will not process it after receiving it, thus realizing the interval time between instructions.

[0051] The following table is an example of an uplink data encapsulation logic sequence.

[0052]

[0053] Step 103, the data encapsulation and sending module sends the uplink baseband data block to the ground signal sending module.

[0054] The baseband data can be sent to the ground signal sending module through a network or other means. After receiving the baseband data, the ground signal sending module can send it in real time, or store and then read and send it.

[0055] Step 104, the signal sending module encodes and scrambles the baseband data according to the satellite uplink data protocol. After processing the baseband data block into a radio frequency signal, it is sent to the satellite data transmission and broadcast uplink receiving device.

[0056] It is necessary to confirm that the baseband data after encoding and scrambling still meets the satellite uplink data protocol.

[0057] Step 105, wait for the satellite data transmission and broadcast to execute various operations in the uplink injection data.

[0058] Step 106, the signal receiving module receives the data transmission and broadcast downlink signal and processes the radio frequency signal into baseband data according to the satellite uplink data protocol

[0059] Step 107: The data extraction module receives the baseband data parsed by the signal receiving module through the network, and extracts the downlink received baseband data according to the satellite downlink data format definition, and re-extracts the content data.

[0060] Step 108: The data comparison module compares the required content data in the uplink data with the content data re-extracted from the downlink, and obtains a content correctness test report.

[0061] The present invention also provides a remote sensing satellite spread-spectrum digital transmission broadcast uplink and downlink closed-loop test system, including a data generation module, a data encapsulation and transmission module, a signal transmission module, a signal receiving module, a data extraction module, and a data comparison module;

[0062] Among them, the data generation module generates an instruction sequence for operating the satellite digital transmission broadcast uplink receiving device, the satellite digital transmission storage device, and the satellite digital transmission broadcast downlink receiving device according to the satellite uplink data format protocol, the satellite instruction format definition, and the digital transmission broadcast uplink and downlink usage method; at the same time, according to user requirements, it generates the content data required for the uplink data;

[0063] The data encapsulation and transmission module encapsulates the instruction sequence for operating the satellite digital transmission broadcast uplink receiving device, the digital transmission storage device, and the digital transmission broadcast downlink receiving device and the content data required for the uplink data into an uplink baseband data block according to the satellite uplink data protocol;

[0064] The signal transmission module processes the uplink baseband data block into a radio frequency signal according to the satellite uplink data protocol and sends it to the satellite digital transmission broadcast uplink receiving device;

[0065] The signal receiving module re-parses the radio frequency signal sent from the on-board device to the ground into baseband data, and the data extraction module parses and extracts the baseband data to re-extract the content data;

[0066] The data comparison module compares the required content data in the uplink data with the content data extracted and parsed from the downlink to obtain a content correctness test report.

[0067] Among them, the signal transmission module includes a spread-spectrum modulator and an upconverter. The generated baseband signal is encoded, scrambled, modulated, and spread-spectrum by the spread-spectrum modulator to generate an intermediate frequency signal containing the baseband data block information. After adjusting the intermediate frequency signal to an appropriate size, it is input into the upconverter. The upconverter converts the intermediate frequency signal to the radio frequency band, and after adjusting the radio frequency signal to an appropriate size, it is sent to the satellite digital transmission uplink receiving device. Attenuators and power amplifiers can be added according to the signal size and the actual functions of the devices;

[0068] The signal receiving module includes a down-converter and a despreading and demodulating device. After the satellite data transmission downlink receiving device inputs the RF signal into the signal receiving module, the down-converter converts the RF signal to an intermediate frequency. After adjusting the intermediate frequency signal to an appropriate size, it is input into the despreading and demodulating device to despread, demodulate, descramble, and decode the intermediate frequency signal, and re-parse the content data contained in the baseband data. An attenuator and a power amplifier can be added according to the signal size and the actual function of the device.

[0069] The relevant content in the system of the present invention can refer to the specific introduction of the method.

[0070] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical content disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A closed-loop test method for uplink and downlink of remote sensing satellite spread spectrum digital broadcast, characterized in that include: The ground generates a command sequence for operating the satellite data broadcast uplink receiving device, satellite data transmission storage device, and satellite data broadcast downlink receiving device according to the satellite uplink data format protocol, satellite command format definition, and data broadcast uplink and downlink usage methods; at the same time, it generates the content data required for the uplink data according to user needs; According to the satellite uplink data protocol, the instruction sequence for operating the satellite digital broadcast uplink receiving device, the digital storage device, and the digital broadcast downlink receiving device and the content data required for the uplink data are encapsulated together into an uplink baseband data block; The uplink baseband data block is processed into a radio frequency signal according to the satellite uplink data protocol and then sent to the satellite data broadcast uplink receiving device; The satellite data transmission and broadcasting uplink receiving device re-parses the RF signal into baseband data, and executes the instructions in the baseband data, stores and forwards or directly forwards the required content data through the satellite data transmission storage device and the data transmission and broadcasting downlink sending device, and processes it into a RF signal; Satellite digital broadcast downlink transmission equipment sends radio frequency signals to the ground; Re-parse the radio frequency signal into baseband data, parse and extract the baseband data, and re-extract the content data; The required content data in the uplink data is compared with the content data extracted and parsed from the downlink to obtain a content correctness test report.

2. The method according to claim 1, characterized in that: The uplink command format includes a packet main header, a sub-header, and an application data area; The main header includes bytes for representing packet identification, bytes representing packet sequence control, and bytes for packet length; the sub-header includes bytes representing the CCSDS sub-header flag, the PUS remote control packet version number, bytes for correct command response, and bytes for service type and source address; the application data area includes bytes representing the number of bus instructions uploaded this time, data, and check bytes.

3. The method according to claim 1, characterized in that: The uplink data format includes a synchronization header, a VCDU leading header, a VCDU inserting area, a VCDU data unit, and a VCDU error control field; the VCDU data unit includes a BPDU leading header and a BPDU bit stream data area, and the uplink instruction sequence is filled into the BPDU bit stream data area.

4. The method according to claim 1, characterized in that: In the process of encapsulating into uplink baseband data blocks, invalid data or idle frames are added before each uplink instruction. When the onboard device receives invalid data or idle frames, it will enter a waiting state without executing any operation, thereby reserving response time for the onboard device. The onboard device includes a satellite data transmission broadcast uplink receiving device, a satellite data transmission storage device, and a satellite data transmission broadcast downlink receiving device.

5. The method according to claim 4, characterized in that: The amount of invalid data or idle frames that need to be added is calculated as follows: According to the shortest response time or shortest processing time T1 of the onboard device and the data transmission rate v1, T1*v1 is calculated to obtain the amount of data S1 required to fill the idle frame.

6. A remote sensing satellite spread spectrum digital broadcast uplink and downlink closed-loop test system, characterized in that: It includes a data generation module, a data encapsulation and sending module, a signal sending module, a signal receiving module, a data extraction module, and a data comparison module; The data generation module generates a command sequence for operating the satellite data broadcast uplink receiving device, the satellite data transmission storage device, and the satellite data broadcast downlink receiving device according to the satellite uplink data format protocol, the satellite command format definition, and the data broadcast uplink and downlink usage method; at the same time, it generates the content data required for the uplink data according to the user's needs; The data encapsulation and transmission module encapsulates the instruction sequence for operating the satellite data broadcast uplink receiving device, the data storage device, and the data broadcast downlink receiving device together with the content data required for the uplink data into an uplink baseband data block according to the satellite uplink data protocol; The signal sending module processes the uplink baseband data block into a radio frequency signal according to the satellite uplink data protocol and sends it to the satellite data broadcast uplink receiving device; The signal receiving module re-parses the radio frequency signal sent by the satellite equipment to the ground into baseband data, and the data extraction module parses and extracts the baseband data to re-extract the content data; The data comparison module compares the required content data in the uplink data with the content data extracted and parsed in the downlink data to obtain a content correctness test report.

7. The test system according to claim 6, characterized in that: The signal sending module includes a spread spectrum modulator and an up-converter; The generated baseband signal is encoded, scrambled, modulated, and spread through a spread spectrum modulator to generate an intermediate frequency signal containing baseband data block information. The intermediate frequency signal is adjusted to a suitable size and then input into an up-converter. The up-converter converts the intermediate frequency signal to a radio frequency band, and the radio frequency signal is adjusted to a suitable size and then sent to a satellite data transmission uplink receiving device. The signal receiving module includes a downconverter and a despreader demodulator; the downconverter converts the RF signal to an intermediate frequency, adjusts the intermediate frequency signal to an appropriate size, and then inputs the despreader demodulator to despread, demodulate, descramble, and decode the intermediate frequency signal to re-parse the content data contained in the baseband data.

8. The test system according to claim 7, characterized in that: Add attenuators and power amplifiers according to the signal size and the actual function of the equipment.

9. The test system according to claim 6, characterized in that: The uplink data format includes a synchronization header, a VCDU leading header, a VCDU inserting area, a VCDU data unit, and a VCDU error control field; the VCDU data unit includes a BPDU leading header and a BPDU bit stream data area, and the uplink instruction sequence is filled into the BPDU bit stream data area.

10. The test system according to claim 6, characterized in that: In the process of encapsulating into uplink baseband data blocks, invalid data or idle frames are added before each uplink instruction. When the onboard device receives invalid data or idle frames, it will enter a waiting state without executing any operation, thereby reserving response time for the onboard device. The onboard device includes a satellite data transmission broadcast uplink receiving device, a satellite data transmission storage device, and a satellite data transmission broadcast downlink receiving device.

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