Remote sensing satellite spread spectrum data transmission broadcast uplink-downlink closed loop test method and system

Abstract

A closed-loop test method and system for uplink and downlink data transmission broadcasting of remote sensing satellites is proposed, which generates a sequence of instructions for operating onboard equipment; generates the content data required for uplink data; encapsulates the sequence of instructions for operating onboard equipment and the content data required for uplink data into an uplink baseband data block according to the satellite uplink data protocol; processes the uplink baseband data block into radio frequency (RF) signals and sends them to the satellite data transmission broadcasting uplink receiving equipment; the satellite data transmission broadcasting uplink receiving equipment re-parses the RF signals into baseband data, executes the instructions in the baseband data, stores and forwards or directly forwards the required content data, and processes it into RF signals; the satellite data transmission broadcasting downlink transmitting equipment transmits the RF signals to the ground; re-parses the RF signals into baseband data, performs parsing and extraction, and re-extracts the content data; compares the required content data in the uplink data with the content data extracted and parsed from the downlink data to obtain a content correctness test report.

Description

Technical Field

[0001] This invention relates to a whole-satellite testing system suitable for spread spectrum data transmission and broadcasting of remote sensing satellites, belonging to the field of whole-satellite testing of remote sensing satellites. Background Technology

[0002] The data transmission subsystem is one of the important subsystems of remote sensing satellites. Its main function is to perform baseband processing, radio frequency modulation, and power amplification on the raw observation data from the satellite payload, and then transmit it outwards through the data transmission antenna. Traditional data transmission subsystems typically transmit all data to ground stations or relay satellites, requiring high data transmission rates and having no special requirements for signal transmission modes. 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, the needs of remote sensing satellites for data transmission links have changed. In addition to transmitting all data to ground stations, they also need to transmit specific portions of data between users. This has led to the addition of a spread spectrum data transmission broadcast mode to the onboard data transmission subsystem, providing uplink and downlink data capabilities specifically for transmitting specific portions of data between users. During ground testing, it is necessary to verify the uplink and downlink capabilities of this spread spectrum data transmission broadcast mode. The current data transmission test system only supports demodulation of data transmission signals using ordinary modulation methods and does not have the capability to demodulate spread spectrum data transmission signals. Meanwhile, the current testing system only supports one-way communication, meaning it can only send uplink signals to the satellite or receive downlink data from the satellite, lacking the capability for uplink / downlink closed-loop verification. Without redesigning the testing system, it is impossible to perform uplink / downlink closed-loop testing and verification of spread spectrum data transmission broadcasting. Therefore, designing a new integrated satellite testing system is a new challenge. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method and system for closed-loop testing of uplink and downlink spread spectrum data transmission broadcasting for remote sensing satellites, so as to realize closed-loop verification of uplink and downlink spread spectrum data transmission broadcasting signals during satellite ground testing.

[0004] The solution of this invention is: a closed-loop test method for uplink and downlink data transmission broadcasting of remote sensing satellites, comprising:

[0005] Based on the satellite uplink data format protocol, satellite command format definition, and uplink and downlink data transmission and broadcasting usage methods, the ground generates command sequences for operating the satellite data transmission and broadcasting uplink receiving equipment, satellite data transmission storage equipment, and satellite data transmission and broadcasting downlink receiving equipment; at the same time, it generates the content data required for uplink data according to user needs.

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

[0007] The uplink baseband data blocks are processed into radio frequency signals according to the satellite uplink data protocol and then sent to the satellite data transmission and broadcast uplink receiving equipment.

[0008] The satellite data transmission and broadcasting uplink receiving equipment re-parses the radio frequency signal into baseband data and executes the instructions in the baseband data. Through the satellite data transmission storage equipment and the data transmission and broadcasting downlink transmitting equipment, the required content data is stored and forwarded or directly forwarded and processed into radio frequency signals.

[0009] Satellite data transmission broadcast downlink transmission equipment transmits radio frequency signals to the ground;

[0010] The radio frequency signal is re-parsed into baseband data, and the baseband data is parsed and extracted to 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 data to obtain a content correctness test report.

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

[0012] The primary header includes bytes for packet identification, bytes for packet sequence control, and a packet length byte; the secondary header includes bytes for CCSDS secondary header flags, 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 for the number of bus commands, data, and checksums uploaded this time.

[0013] Preferably, the uplink data format includes a synchronization header, a VCDU master header, a VCDU insertion area, a VCDU data unit, and a VCDU error control field; the VCDU data unit includes a BPDU master 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 encapsulation into uplink baseband data blocks, invalid data or idle frames are added before each uplink command. When the on-board equipment receives invalid data or idle frames, it will enter a waiting state without performing any operations, thereby reserving response time for the on-board equipment. The on-board equipment includes satellite data transmission and broadcast uplink receiving equipment, satellite data transmission and storage equipment, and satellite data transmission and broadcast downlink receiving equipment.

[0015] The preferred method for calculating the amount of invalid data or idle frames that need to be added is as follows:

[0016] Based on the shortest response time or shortest processing time T1 of the on-board equipment and the data transmission rate v1, calculate T1*v1 to obtain the amount of data S1 that needs to be filled in the idle frame.

[0017] A ground test system for uplink and downlink closed-loop remote sensing satellite spread spectrum data transmission and broadcasting includes 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 instruction sequences for operating the satellite data transmission and broadcasting uplink receiving device, satellite data transmission storage device, and satellite data transmission and broadcasting downlink receiving device, based on the satellite uplink data format protocol, satellite command format definition, and data transmission and broadcasting uplink and downlink usage methods; at the same time, it generates the content data required for uplink data according to user needs.

[0019] The data encapsulation and transmission module encapsulates the instruction sequence for operating the satellite data transmission and broadcast uplink receiving device, data transmission storage device, and data transmission and broadcast downlink receiving device, along with the content data required for 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 radio frequency signals according to the satellite uplink data protocol and then sends them to the satellite data transmission and broadcast uplink receiving equipment.

[0021] The signal receiving module re-parses the radio frequency signals sent from 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;

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

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

[0024] The generated baseband signal is encoded, scrambled, modulated, and spread by a spread spectrum modulator to generate an intermediate frequency (IF) signal containing baseband data block information. After the IF signal is adjusted to an appropriate size, it is input into an upconverter. The upconverter converts the IF signal to the radio frequency (RF) band. After the RF signal is adjusted to an appropriate size, it is sent to the satellite data transmission uplink receiving equipment.

[0025] The signal receiving module includes a downconverter and a despreading demodulator. The downconverter converts the radio frequency signal to an intermediate frequency (IF). After adjusting the IF signal to a suitable value, it is input to the despreading demodulator to despread, demodulate, descramble, and decode the IF signal, thus re-analyzing the data contained in the baseband data.

[0026] Preferably, an attenuator and a power amplifier are added, depending on the signal strength and the actual function of the device.

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

[0028] Preferably, during the encapsulation into uplink baseband data blocks, invalid data or idle frames are added before each uplink command. When the on-board equipment receives invalid data or idle frames, it will enter a waiting state without performing any operations, thereby reserving response time for the on-board equipment. The on-board equipment includes satellite data transmission and broadcast uplink receiving equipment, satellite data transmission and storage equipment, and satellite data transmission and broadcast downlink receiving equipment.

[0029] The advantages of this invention compared to the prior art are:

[0030] This invention provides a method for generating uplink signals and processing downlink signals for spread spectrum data transmission from remote sensing satellites, and also provides a fully automated closed-loop comparison and verification method for uplink and downlink data, which can improve the efficiency and reliability of testing remote sensing satellite data transmission subsystems.

[0031] Advantage 1: In previous tests, commands and data were sent separately. This required sending the satellite device power-on command first, then the data, then the data reception command, then the data download command, and finally the satellite device shutdown command. This involved numerous operations and was time-consuming. This invention encapsulates commands and data simultaneously into a data block for transmission, enabling the satellite to automatically execute all commands. This allows the satellite to automatically power on, receive, download, and power off the device in a specific sequence, requiring no additional operations. This high degree of automation saves time.

[0032] Advantage 2: When a satellite uses the uplink channel, the ordinary command uplink channel and the spread spectrum data broadcast uplink channel are two completely different channels for the satellite, requiring switching of ground transmission equipment. Since uplink data must be transmitted via spread spectrum data broadcast, previously, transmitting uplink data required switching to the ordinary command uplink equipment to send commands, then switching to the spread spectrum data broadcast uplink equipment to send data, and then switching back to the ordinary command uplink equipment to send commands—a complex process. This invention allows both commands and data to be input to the satellite via the data broadcast uplink channel. During operation, there is no need to switch between the ordinary command uplink channel and the spread spectrum data broadcast uplink channel; all operations can be completed using the same set of ground equipment, making it much simpler to use.

[0033] Advantage 3: Existing technologies require manual comparison after receiving downlink data. This invention uses a signal receiving 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. Attached Figure Description

[0034] Figure 1This is a flowchart of the steps of the remote sensing satellite spread spectrum data transmission and broadcasting uplink and downlink closed-loop test method of the present invention;

[0035] Figure 2 This is a schematic diagram of the uplink and downlink closed-loop test system for remote sensing satellite spread spectrum data transmission broadcasting according to the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the embodiments.

[0037] This invention discloses a closed-loop test method for spread spectrum data transmission and broadcasting uplink and downlink of remote sensing satellites. It can be mainly applied to remote sensing satellites with data transmission and broadcasting uplink and downlink functions, and can verify the data transmission and broadcasting uplink and downlink functions and links during ground testing.

[0038] The remote sensing satellite spread spectrum data transmission broadcast uplink and downlink closed-loop test method includes:

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

[0040] The uplink injected data can be determined and input by the user according to actual task requirements. It also needs to refer to the satellite uplink data format protocol, satellite command format definition, and data transmission broadcast uplink and downlink usage methods to generate a complete data file containing uplink command formats for operating the satellite uplink data transmission broadcast uplink receiving device, satellite data transmission storage device, and satellite data transmission broadcast downlink receiving device. Simultaneously, according to user needs, the required uplink data content is generated and stored in the storage area.

[0041] The table below shows an example of an uplink command format.

[0042]

[0043]

[0044] Step 102: The data encapsulation and sending module encapsulates the uplink injected data.

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

[0046] The table below shows an example of an uplink data format, where uplink commands are directly filled into the BPDU bitstream data area.

[0047]

[0048] Because on-board equipment requires response time, invalid data or idle frames need to be added before each execution command to fill the gap. When the on-board equipment receives invalid data or idle frames, it will enter a waiting state without performing any operations, thus reserving response time for the on-board equipment.

[0049] Based on the shortest response time T1 of the onboard equipment and the data transmission rate v1, calculate T1*v1 to obtain the amount of data S1 that needs to be filled in the idle frame.

[0050] When satellite commands are typically sent as a sequence for uplink, to allow sufficient response or data processing time for the equipment, an interval needs to be set for each command during the command sequence creation process, such as command 1 - interval 1s - command 2. After being sent to the satellite through a normal command uplink channel, the satellite automatically parses the interval time, thus achieving time-sequential command transmission. This invention, however, encapsulates commands as data blocks and uploads them through a data broadcast uplink channel. Since devices using this channel cannot automatically parse the interval time via the satellite, it is impossible to set the time interval within the data block. Therefore, this invention proposes inserting idle frames between commands, such as command 1 - idle frame - command 2. Idle frames consume channel bandwidth during uplink, but the satellite does not process them upon receipt, thus achieving the desired interval time between commands.

[0051] The table below shows an example of an uplink data encapsulation logic sequence.

[0052]

[0053] Step 103: The data encapsulation and transmission module sends the uplink baseband data block to the ground signal transmission module.

[0054] Baseband data can be transmitted to the ground signal transmission module via networks or other means. After receiving the baseband data, the ground signal transmission module can either transmit it in real time or store it and then read and transmit it.

[0055] Step 104: The signal transmission module encodes and scrambles the baseband data according to the satellite uplink data protocol, processes the baseband data block into radio frequency signals, and then sends it to the satellite data transmission broadcast uplink receiving device.

[0056] It is necessary to confirm that the encoded and scrambled baseband data still meets the satellite uplink data protocol.

[0057] Step 105: Wait for the satellite data transmission broadcast to execute the various operations in the uplink injected data.

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

[0059] Step 107: The data extraction module extracts the baseband data parsed by the network signal receiving module 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 upstream data with the content data re-extracted from the downstream data to obtain a content correctness test report.

[0061] The present invention also provides a remote sensing satellite spread spectrum data 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 reception module, a data extraction module, and a data comparison module;

[0062] The data generation module generates instruction sequences for operating the satellite data transmission and broadcasting uplink receiving device, satellite data transmission storage device, and satellite data transmission and broadcasting downlink receiving device, based on the satellite uplink data format protocol, satellite command format definition, and data transmission and broadcasting uplink and downlink usage methods; at the same time, it generates the content data required for uplink data according to user needs.

[0063] The data encapsulation and transmission module encapsulates the instruction sequence for operating the satellite data transmission and broadcast uplink receiving device, data transmission storage device, and data transmission and broadcast downlink receiving device, along with the content data required for 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 radio frequency signals according to the satellite uplink data protocol and then sends them to the satellite data transmission and broadcast uplink receiving equipment.

[0065] The signal receiving module re-parses the radio frequency signals sent from 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;

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

[0067] The signal transmission module includes a spread spectrum modulator and an upconverter. The generated baseband signal is encoded, scrambled, modulated, and spread by the spread spectrum modulator to generate an intermediate frequency (IF) signal containing baseband data block information. After the IF signal is adjusted to an appropriate value, it is input to the upconverter, which converts the IF signal to the radio frequency (RF) band. The RF signal is then adjusted to an appropriate value and transmitted to the satellite data transmission uplink receiving equipment. Attenuators and power amplifiers can be added depending on the signal strength and the actual functionality of the equipment.

[0068] The signal receiving module includes a downconverter and a despreader / demodulator. After the satellite data transmission downlink receiving equipment inputs the radio frequency (RF) signal to the signal receiving module, the downconverter converts the RF signal to an intermediate frequency (IF). The IF signal is then adjusted to a suitable level and input to the despreader / demodulator for despreading, demodulation, descrambling, and decoding, re-analyzing the data contained in the baseband data. Attenuators and power amplifiers can be added depending on the signal strength and the actual functionality of the equipment.

[0069] For details regarding the system of this invention, please refer to the specific description of the method.

[0070] Although the present invention has been disclosed above with reference to 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 solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A closed-loop test method for uplink and downlink data transmission broadcasting of remote sensing satellites, characterized in that... include: Based on the satellite uplink data format protocol, satellite command format definition, and uplink and downlink data transmission and broadcasting usage methods, the ground generates command sequences for operating the satellite data transmission and broadcasting uplink receiving equipment, satellite data transmission storage equipment, and satellite data transmission and broadcasting downlink transmitting equipment; at the same time, it generates the content data required for uplink data according to user needs. According to the satellite uplink data protocol, the instruction sequence for operating the satellite data transmission and broadcast uplink receiving equipment, data transmission storage equipment, and data transmission and broadcast downlink transmitting equipment, together with the content data required for uplink data, are encapsulated into an uplink baseband data block; The uplink baseband data blocks are processed into radio frequency signals according to the satellite uplink data protocol and then sent to the satellite data transmission and broadcast uplink receiving equipment. The satellite data transmission and broadcasting uplink receiving equipment re-parses the radio frequency signal into baseband data and executes the instructions in the baseband data. Through the satellite data transmission storage equipment and the data transmission and broadcasting downlink transmitting equipment, the required content data is stored and forwarded or directly forwarded and processed into radio frequency signals. Satellite data transmission broadcast downlink transmission equipment transmits radio frequency signals to the ground; The radio frequency signal is re-analyzed into baseband data, and the baseband data is parsed and extracted to extract the content data. The required content data in the upstream data is compared with the content data extracted and parsed from the downstream data to obtain a content correctness test report; During the encapsulation of uplink baseband data blocks, invalid data or idle frames are added before each uplink command. When the on-board equipment receives invalid data or idle frames, it will enter a waiting state without performing any operations, thereby reserving response time for the on-board equipment. The on-board equipment includes satellite data transmission and broadcast uplink receiving equipment, satellite data transmission and storage equipment, and satellite data transmission and broadcast downlink transmitting equipment.

2. The method according to claim 1, characterized in that: The uplink instruction format includes a packet header, a sub-header, and an application data area; The primary header includes bytes for packet identification, bytes for packet sequence control, and a packet length byte; the secondary header includes bytes for CCSDS secondary header flags, 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 for the number of bus commands, data, and checksums uploaded this time.

3. The method according to claim 1, characterized in that: The uplink data format includes a synchronization header, a VCDU master header, a VCDU insertion area, a VCDU data unit, and a VCDU error control field; the VCDU data unit includes a BPDU master 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: The calculation method for the amount of invalid data or idle frames that need to be added is as follows: Calculate T1 based on the shortest response time or shortest processing time T1 of the on-board equipment and the data transmission rate v1. v1 obtains the amount of data S1 that needs to be filled in the free frame.

5. A remote sensing satellite spread spectrum data transmission and broadcast uplink and downlink closed-loop test system, characterized in that: It includes 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; The data generation module generates instruction sequences for operating the satellite data transmission and broadcasting uplink receiving device, satellite data transmission storage device, and satellite data transmission and broadcasting downlink transmitting device, based on the satellite uplink data format protocol, satellite command format definition, and data transmission and broadcasting uplink and downlink usage methods; at the same time, it generates the content data required for uplink data according to user needs. The data encapsulation and transmission module encapsulates the instruction sequence for operating the satellite data transmission and broadcast uplink receiving device, data transmission storage device, and data transmission and broadcast downlink transmitting device, along with the content data required for uplink data, into an uplink baseband data block according to the satellite uplink data protocol. The signal transmission module processes the uplink baseband data block into radio frequency signals according to the satellite uplink data protocol and then sends them to the satellite data transmission and broadcast uplink receiving equipment. The satellite data transmission and broadcasting uplink receiving equipment re-parses the radio frequency signal into baseband data and executes the instructions in the baseband data. Through the satellite data transmission storage equipment and the data transmission and broadcasting downlink transmitting equipment, the required content data is stored and forwarded or directly forwarded and processed into radio frequency signals. The signal receiving module re-parses the radio frequency signal sent to the ground by the satellite data transmission and broadcast downlink transmitting equipment into baseband data. The data extraction module then parses and extracts the baseband data to re-extract the content data. The data comparison module compares the required content data in the upstream data with the content data extracted and parsed from the downstream data to obtain a content correctness test report; During the encapsulation of uplink baseband data blocks, invalid data or idle frames are added before each uplink command. When the on-board equipment receives invalid data or idle frames, it will enter a waiting state without performing any operations, thereby reserving response time for the on-board equipment. The on-board equipment includes satellite data transmission and broadcast uplink receiving equipment, satellite data transmission and storage equipment, and satellite data transmission and broadcast downlink transmitting equipment.

6. The testing system according to claim 5, characterized in that: The signal transmission module includes a spread spectrum modulator and an up-converter; The generated baseband signal is encoded, scrambled, modulated, and spread by a spread spectrum modulator to generate an intermediate frequency (IF) signal containing baseband data block information. After the IF signal is adjusted to an appropriate size, it is input into an upconverter. The upconverter converts the IF signal to the radio frequency (RF) band. After the RF signal is adjusted to an appropriate size, it is sent to the satellite data transmission uplink receiving equipment. The signal receiving module includes a downconverter and a despreading demodulator. The downconverter converts the radio frequency signal to an intermediate frequency (IF). After adjusting the IF signal to a suitable value, it is input to the despreading demodulator to despread, demodulate, descramble, and decode the IF signal, thus re-analyzing the data contained in the baseband data.

7. The testing system according to claim 6, characterized in that: Depending on the signal strength and the actual function of the equipment, add attenuators and power amplifiers.

8. The testing system according to claim 5, characterized in that: The uplink data format includes a synchronization header, a VCDU master header, a VCDU insertion area, a VCDU data unit, and a VCDU error control field; the VCDU data unit includes a BPDU master header and a BPDU bit stream data area, and the uplink instruction sequence is filled into the BPDU bit stream data area.

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