Spacecraft autonomous anti-jamming TT&C system for complex electromagnetic environment

Abstract

This invention relates to an autonomous anti-interference telemetry and control system for spacecraft operating in complex electromagnetic environments, comprising a multi-mode transponder and a radio eavesdropping device. The multi-mode transponder possesses three telemetry and control capabilities: on-demand access telemetry and control, spread spectrum telemetry and control, and spread frequency hopping telemetry and control. It can autonomously switch telemetry and control systems based on switching commands from the radio eavesdropping device. The radio eavesdropping device continuously monitors the electromagnetic spectrum arriving at the spacecraft, identifying whether the monitored signal matches the spectral characteristics of the telemetry and control system used by the spacecraft, and sending a switching command to the multi-mode transponder when a match is found. This invention can adaptively switch the spacecraft's telemetry and control system based on the status of the ground telemetry and control system, and can autonomously use the spread frequency hopping telemetry and control system in complex electromagnetic environments, ensuring the safety and reliability of telemetry and control missions.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft design technology and relates to a satellite telemetry and control system that can autonomously resist interference in complex electromagnetic environments. It is suitable for spacecraft with high requirements for telemetry and control safety and reliability. Background Technology

[0002] When a spacecraft is in orbit, ground control is achieved by establishing a wireless telemetry and control channel with the spacecraft. Currently available telemetry and control systems mainly include on-demand access telemetry and control, spread spectrum telemetry and control, and spread frequency hopping telemetry and control.

[0003] In the "on-demand access" telemetry and control system, "on-demand" means that when a spacecraft enters a controllable airspace, it actively initiates a telemetry and control mission; when it leaves the controllable airspace, it actively ceases the mission. The characteristic of this system is that the spacecraft intermittently transmits downlink information according to its own needs, with information appearing suddenly (suddenly), maintaining radio silence most of the time, making it difficult to be detected by electronic reconnaissance and reducing the frequency of information transmission. Spread spectrum and spread frequency hopping telemetry and control systems differ from the on-demand system in that they continuously transmit downlink information, with information appearing continuously (constantly). The spread frequency hopping system has strong anti-interference capabilities, ensuring reliable telemetry and control missions, but its information transmission rate is relatively low, meaning its telemetry and control information transmission efficiency is lower than that of the spread spectrum and on-demand systems. The spread spectrum system, on the other hand, combines high information transmission efficiency with anti-interference capabilities. While its anti-interference capability is significantly lower than that of the spread frequency hopping system, its information transmission efficiency is higher than that of the on-demand access and spread frequency hopping systems.

[0004] Currently, when tracking and controlling spacecraft using different systems, it is necessary to pre-agree with the ground system to ensure consistency between the spacecraft and the ground-based tracking and control system. This approach offers relatively limited flexibility and lacks the ability to autonomously switch between systems in complex electromagnetic environments. For example, if the spacecraft is operating in an on-demand tracking and control system, the ground also needs to be equipped with on-demand access tracking and control equipment and keep it online to establish a tracking and control channel with the spacecraft. If the ground wants to use a spread spectrum tracking and control system, it must first send commands to the spacecraft through the on-demand access tracking and control equipment to remotely switch the spacecraft to the spread spectrum tracking and control system before it can use the ground-based spread spectrum tracking and control equipment to establish a spread spectrum tracking and control channel with the spacecraft. If the spacecraft experiences strong interference that renders the on-demand access channel inoperable, it will be unable to switch to the more interference-resistant spread spectrum hopping system to perform tracking and control functions. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a telemetry and control system that can adaptively switch the spacecraft telemetry and control system according to the state of the ground telemetry and control system, and can autonomously use the spread frequency hopping telemetry and control system in complex electromagnetic environments, so as to ensure the safety and reliability of the telemetry and control mission.

[0006] The solution of the present invention is: An autonomous anti-interference telemetry and control system for spacecraft designed for complex electromagnetic environments includes: a multi-mode transponder and a radio listening device; The multi-mode transponder has three telemetry and control capabilities: on-demand access telemetry and control, spread spectrum telemetry and control, and spread frequency hopping telemetry and control. It can autonomously switch telemetry and control modes according to the switching command of the radio listening device. The radio listening device continuously monitors the electromagnetic spectrum arriving at the spacecraft, and can identify whether the monitored signal matches the spectrum characteristics of the telemetry and control system used by the spacecraft, and send a switching command to the multi-mode transponder when a match is found. The multi-mode transponder is equipped with a high-frequency cable and a remote control and telemetry signal transceiver antenna, which are used to receive uplink remote control wireless signals transmitted from the ground or to transmit downlink signals to the ground. The radio listening device is equipped with a high-frequency cable and a radio listening antenna to receive various uplink wireless signals.

[0007] Preferably, the multi-mode transponder operates in only one telemetry and control system at any given time, with the default operating mode being the on-demand access telemetry and control system. The transponder's receiver can receive remote control information sent by the on-demand access telemetry and control equipment on the ground and periodically send downlink telemetry information to the ground.

[0008] Preferably, when the radio listening device continuously monitors the electromagnetic spectrum arriving at the spacecraft, it is able to identify abnormal spectra.

[0009] Preferably, the abnormal spectrum includes high-power broadband interference, narrowband interference, and pulse interference.

[0010] Preferably, the multi-mode transponder autonomously switches the telemetry and control system according to the switching command of the radio listening device, as follows: (a) When the spacecraft has a high information transmission efficiency requirement, it sends the spread spectrum telemetry and control mission request to the ground through the downlink of the on-demand access telemetry and control system. The ground responds to the request, and then the spacecraft and the ground switch to the spread spectrum telemetry and control system. The spacecraft sends telemetry information to the ground in the normal transmission mode to carry out the telemetry and control mission with a high information transmission rate. After the spread spectrum telemetry and control system mission is completed, the radio listening device sends the on-demand access telemetry and control system switching command to autonomously switch the multi-mode transponder to the on-demand access telemetry and control system and stop the normal transmission mode. (b) When there is a need for high information transmission efficiency on the ground, the uplink signal is sent directly through the spread spectrum telemetry and control system equipment. After receiving the uplink signal, the spacecraft's radio listening device identifies the carrier frequency, occupied bandwidth, Doppler characteristics, and signal energy of the spectrum. If it is determined that the signal characteristics match those of the spread spectrum telemetry and control system used by the spacecraft, the radio listening device sends a spread spectrum telemetry and control system switching command to the multi-mode transponder, which then autonomously switches the multi-mode transponder to the spread spectrum telemetry and control system. The multi-mode transponder then captures and synchronizes the uplink signal and continuously transmits the spread spectrum telemetry and control system signal to the ground, thus completing the spread spectrum telemetry and control system task. When the uplink signal of the spread spectrum telemetry and control system is turned off on the ground, the multi-mode transponder cannot capture the uplink signal, and the radio listening device cannot detect the uplink signal either. In this case, the radio listening device sends an on-demand access telemetry and control system switching command to the multi-mode transponder, which then autonomously switches the multi-mode transponder to the on-demand access telemetry and control system. (c) When there is a high anti-interference telemetry and control requirement on the ground, the uplink signal is directly transmitted through the spread frequency hopping telemetry and control system equipment. After receiving the uplink signal, the spacecraft's radio listening device identifies the carrier frequency, occupied bandwidth, Doppler characteristics, and signal energy of the spectrum. If it is determined that the signal characteristics match those of the spread frequency hopping telemetry and control system used by the spacecraft, the radio listening device sends a spread frequency hopping telemetry and control system switching command to the multi-mode transponder, switching the multi-mode transponder to the spread frequency hopping telemetry and control system. The multi-mode transponder then captures and synchronizes the uplink signal and continuously transmits the spread frequency hopping telemetry and control system signal to the ground, thus completing the spread frequency hopping telemetry and control system task. When the uplink signal of the spread frequency hopping telemetry and control system is turned off on the ground, the multi-mode transponder cannot capture the uplink signal, and the radio listening device cannot detect the uplink signal either. In this case, the radio listening device sends an on-demand access telemetry and control system switching command to the multi-mode transponder, autonomously switching the multi-mode transponder to the on-demand access telemetry and control system.

[0011] Preferably, in (b), if the radio eavesdropping receiver receives an uplink signal but identifies it as not matching the signal characteristics of the spread spectrum telemetry and control system used by the spacecraft, it will not switch the operating mode of the multi-mode transponder; if the radio eavesdropping receiver identifies the uplink signal as matching the signal characteristics of the spread spectrum telemetry and control system used by the spacecraft and switches the multi-mode transponder to spread spectrum mode, but the multi-mode transponder cannot capture and synchronize the uplink signal after the switch, it will maintain this state, and the multi-mode transponder will continue to search and capture. If it still cannot capture and synchronize after 1 minute, the radio eavesdropping receiver will send an on-demand access telemetry and control system switching command to the multi-mode transponder, and the multi-mode transponder will automatically switch to the on-demand access telemetry and control system.

[0012] Preferably, in (c), if the radio eavesdropping device receives an uplink signal but identifies it as not matching the signal characteristics of the spread frequency hopping telemetry and control system used by the spacecraft, it will not switch the operating mode of the multi-mode transponder; if the radio eavesdropping device identifies the uplink signal as matching the signal characteristics of the spread frequency hopping telemetry and control system used by the spacecraft and switches the multi-mode transponder to the spread frequency hopping mode, but the multi-mode transponder cannot capture and synchronize the uplink signal after the switch, it will maintain this state, and the multi-mode transponder will continue to search and capture. If it still cannot capture and synchronize after 2 minutes, the radio eavesdropping device will send an on-demand access telemetry and control system switching command to the multi-mode transponder, and the multi-mode transponder will automatically switch to the on-demand access telemetry and control system.

[0013] Preferably, in (c), if the radio receiver receives an uplink signal but identifies it as an abnormal spectrum, it is determined that the spacecraft is under telemetry and control interference. At this time, the multi-mode transponder is immediately turned off, and the transmitting section is kept electromagnetically silent. The radio receiver then continues to monitor the abnormal spectrum. If the abnormal spectrum disappears within 10 minutes, the multi-mode transponder is turned on and restored to the on-demand access telemetry and control system, entering normal working status. If the abnormal spectrum can still be detected after more than 10 minutes, it is considered that the spacecraft has suffered targeted interference. The multi-mode transponder is turned on and switched to spread frequency hopping mode, and the transmitter is turned on to send an event report of targeted interference to the ground. If the abnormal spectrum can still be detected after more than 20 minutes, the receiver of the multi-mode transponder is turned on, and the anti-interference capability of the channel is utilized to wait for the ground to send a spread frequency hopping uplink signal for further processing.

[0014] Preferably, if the abnormal spectrum disappears between 10 and 20 minutes, the multi-mode transponder is restored to the on-demand access telemetry and control system, and the receiver and transmitter of the multi-mode transponder are restored to operation.

[0015] Preferably, the telemetry and control system is used in any situation, adopting a space-based mode, with the uplink carrier using the F1 frequency point and the downlink carrier using the F2 frequency point, both occupying a bandwidth of ±3.5MHz; The spread spectrum telemetry and control system communicates directly with the ground station. The uplink carrier uses the F3 frequency point, and the downlink carrier uses the F4 frequency point, both occupying a bandwidth of ±3.5MHz. The extended frequency hopping telemetry and control system communicates directly with the ground station. The uplink carrier uses the F5 frequency point, and the downlink carrier uses the F6 frequency point, both occupying a bandwidth of ±50MHz.

[0016] The advantages of this invention compared to the prior art are: (1) Traditional spacecraft telemetry and control missions require prior agreement with the ground system. This invention does not require prior agreement. The spacecraft can switch from on-demand telemetry and control to spread spectrum telemetry and control or spread frequency hopping telemetry and control; the ground can also switch between different telemetry and control systems as needed, and the spacecraft can adaptively switch, thereby greatly improving flexibility.

[0017] (2) When the spacecraft is subjected to unintentional interference, it autonomously shuts down the transponder to prevent damage to the unit; it autonomously shuts down the transmitter to maintain electromagnetic silence; when the spacecraft is subjected to targeted interference, it first autonomously sends an event report to the ground, and then establishes a high anti-interference spread frequency hopping telemetry and control system channel according to the situation, so that the ground can further handle the situation and ensure the safety and reliability of the telemetry and control mission. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the measurement and control system. Figure 2 This is a schematic diagram showing the switching of the on-orbit operation status of the telemetry and control system. Detailed Implementation

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] The spacecraft's telemetry, tracking, and command (TT&C) system of this invention is equipped with a multi-mode transponder, a radio eavesdropping device, and peripheral high-frequency cables, antennas, and other related equipment. The multi-mode transponder possesses TT&C capabilities across three modes: on-demand access, spread spectrum, and spread frequency hopping. It can switch between different TT&C modes based on commands, operating only in one mode at a time, typically the on-demand access mode. The radio eavesdropping device continuously monitors the electromagnetic spectrum arriving at the spacecraft, identifying the spectral characteristics of the TT&C mode used by the spacecraft and detecting abnormal spectra such as high-power broadband interference, narrowband interference, and pulse interference. The peripheral high-frequency cables, antennas, and other equipment are primarily used for radio reception and transmission.

[0021] Under normal circumstances, multi-mode transponders operate in an on-demand access telemetry and control system. The transponder's receiver can receive remote control information sent by on-the-ground on-demand access telemetry and control equipment and periodically send downlink telemetry information to the ground.

[0022] Figure 2 The following is a schematic diagram illustrating the switching of the on-orbit operation status of the telemetry and control system: (a) When the spacecraft has a high information transmission rate requirement (e.g., 4kbps uplink and 8kbps downlink), it sends the spread spectrum telemetry and control mission request to the ground via the on-demand access telemetry and control downlink. The ground responds to the request, and then the spacecraft and the ground switch to the spread spectrum telemetry and control system. The spacecraft sends telemetry information to the ground in the normal transmission mode to carry out the high information transmission rate telemetry and control mission. After the spread spectrum telemetry and control system mission is completed, the spacecraft autonomously switches to the on-demand access telemetry and control system and stops the normal transmission mode.

[0023] (b) When there is a high information transmission rate requirement on the ground, uplink signals can be sent directly through the spread spectrum telemetry and control system equipment. After receiving the signal, the spacecraft's radio receiver identifies the characteristics of the spectrum, such as carrier frequency, occupied bandwidth, Doppler characteristics, and signal energy. If it is determined that the characteristics match the spread spectrum telemetry and control system signal used by the spacecraft, it will autonomously switch the multi-mode transponder to the spread spectrum telemetry and control system. The multi-mode transponder will then capture and synchronize the uplink signal and continuously transmit the spread spectrum telemetry and control system signal to the ground, thus completing the spread spectrum telemetry and control system task. When the uplink signal of the spread spectrum telemetry and control system is turned off on the ground, the multi-mode transponder cannot capture the uplink signal, and the radio receiver cannot detect the uplink signal. In this case, the spacecraft will then autonomously switch the multi-mode transponder to the on-demand access telemetry and control system.

[0024] In step (b), if the radio eavesdropping receiver receives the uplink signal but identifies it as not matching the signal characteristics of the spread spectrum telemetry and control system used by the spacecraft, it will not switch the operating mode of the multi-mode transponder. If the radio eavesdropping receiver identifies the uplink signal as matching the signal characteristics of the spread spectrum telemetry and control system used by the spacecraft and switches the multi-mode transponder to spread spectrum mode, but the multi-mode transponder cannot capture and synchronize the uplink signal after the switch, it will maintain this state and the multi-mode transponder will continue to search and capture. If it still cannot capture and synchronize after 1 minute, the spacecraft will then autonomously switch the multi-mode transponder to the on-demand access telemetry and control system.

[0025] (c) When there is a high anti-interference telemetry and control requirement on the ground, uplink signals can be sent directly through the spread frequency hopping telemetry and control system equipment. After receiving the signal, the spacecraft's radio listening device identifies the characteristics of the spectrum, such as carrier frequency, occupied bandwidth, Doppler characteristics, and signal energy. If it is determined that the characteristics match the spread frequency hopping telemetry and control system signal used by the spacecraft, it will autonomously switch the multi-mode transponder to the spread frequency hopping telemetry and control system. The multi-mode transponder will then capture and synchronize the uplink signal and continuously transmit the spread frequency hopping telemetry and control system signal to the ground, thus completing the spread frequency hopping telemetry and control system task. When the uplink signal of the spread frequency hopping telemetry and control system is turned off on the ground, the multi-mode transponder cannot capture the uplink signal, and the radio listening device cannot detect the uplink signal. Then, it will autonomously switch the multi-mode transponder to the random access telemetry and control system.

[0026] If the radio receiver receives an uplink signal but determines that it does not match the signal characteristics of the spread frequency hopping telemetry and control system used by the spacecraft, it will not switch the operating mode of the multi-mode transponder. If the radio receiver determines that the uplink signal matches the signal characteristics of the spread frequency hopping telemetry and control system used by the spacecraft and switches the multi-mode transponder to spread frequency hopping mode, but the multi-mode transponder cannot capture and synchronize the uplink signal after the switch, it will maintain this state and the multi-mode transponder will continue to search and capture. If it still cannot capture and synchronize after 2 minutes, the spacecraft will then autonomously switch the multi-mode transponder to the random access telemetry and control system.

[0027] If the radio receiver receives an uplink signal but identifies it as having abnormally high signal energy and a spectrum consistent with broadband or narrowband noise characteristics, it is determined that the spacecraft is under telemetry and control interference. In this case, the multi-mode transponder is immediately shut down to prevent damage to the receiver and to maintain electromagnetic silence on the transmitter. The radio receiver then continues to monitor the abnormal spectrum. If the abnormal spectrum disappears within 10 minutes, the multi-mode transponder is restarted and restored to the on-demand access telemetry and control system, resuming normal operation. If the abnormal spectrum is still detected after 10 minutes, it is considered that the spacecraft has suffered targeted interference. The multi-mode transponder is restarted and switched to spread-frequency hopping mode, and the transmitter is turned on to send a report of the targeted interference to the ground. If the abnormal spectrum is still detected after 20 minutes, the receiver of the multi-mode transponder is turned on, utilizing the channel's strong interference resistance, while waiting for the ground to send a spread-frequency hopping uplink signal for further action. If the abnormal spectrum disappears between 10 and 20 minutes, the multi-mode transponder is restored to the on-demand access telemetry and control system, and both the receiver and transmitter of the multi-mode transponder are restored to operation.

[0028] The spacecraft configuration of this invention is as follows Figure 1 The measurement and control system shown.

[0029] The multi-mode transponder is the core unit for completing telemetry and control (TT&C) tasks, possessing three capabilities: on-demand TT&C, spread spectrum TT&C, and spread frequency hopping TT&C. It generally operates in the on-demand TT&C mode, switching between different TT&C modes under control. The on-demand TT&C mode uses a space-based (i.e., communication with the ground via relay satellite) mode, with the uplink carrier using frequency F1 and the downlink carrier using frequency F2, each occupying a bandwidth of ±3.5MHz. The spread spectrum TT&C mode communicates directly with the ground station, with the uplink carrier using frequency F3 and the downlink carrier using frequency F4, each occupying a bandwidth of ±3.5MHz. The spread frequency hopping TT&C mode communicates directly with the ground station, with the uplink carrier using frequency F5 and the downlink carrier using frequency F6, each occupying a bandwidth of ±50MHz.

[0030] The radio eavesdropping device is equipped with uplink spectral characteristic parameters for the ad-hoc access telemetry and control (TT&C) system (F1±3.5MHz), the spread spectrum TT&C system (F3±3.5MHz), and the spread frequency hopping TT&C system (F5±50MHz), all used by the multi-mode transponder. Verification has shown that it can accurately identify the uplink spectrum used by the multi-mode transponder. The processor in the radio eavesdropping device can analyze the received radio spectrum characteristics, distinguishing not only the three different TT&C systems used by this spacecraft but also identifying broadband and narrowband interference. After identification, the radio eavesdropping device sends the identification result and switching command to the multi-mode transponder.

[0031] The multi-mode transponder is equipped with a high-frequency cable and a remote control and telemetry signal transceiver antenna to receive uplink remote control wireless signals sent from the ground or to send downlink signals to the ground.

[0032] The radio listening device is equipped with a high-frequency cable and a radio listening antenna to receive various uplink wireless signals.

[0033] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments, characterized in that: include: Multimode transponder, radio listening device; The multi-mode transponder has three telemetry and control capabilities: on-demand access telemetry and control, spread spectrum telemetry and control, and spread frequency hopping telemetry and control. It can autonomously switch telemetry and control modes according to the switching command of the radio listening device. The radio listening device continuously monitors the electromagnetic spectrum arriving at the spacecraft, and can identify whether the monitored signal matches the spectrum characteristics of the telemetry and control system used by the spacecraft, and send a switching command to the multi-mode transponder when a match is found. The multi-mode transponder is equipped with a high-frequency cable and a remote control and telemetry signal transceiver antenna, which are used to receive uplink remote control wireless signals transmitted from the ground or to transmit downlink signals to the ground. The radio listening device is equipped with a high-frequency cable and a radio listening antenna to receive various uplink wireless signals.

2. The spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 1, characterized in that: The multi-mode transponder operates in only one telemetry and control system at any given time. It defaults to the on-demand access telemetry and control system. The transponder's receiver can receive remote control information sent by the on-demand access telemetry and control equipment on the ground and periodically send downlink telemetry information to the ground.

3. The spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 1, characterized in that: When a radio receiver continuously monitors the electromagnetic spectrum arriving at a spacecraft, it can identify abnormal spectra.

4. The spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 3, characterized in that: The abnormal spectrum includes high-power broadband interference, narrowband interference, and pulse interference.

5. The spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 1, characterized in that: The multi-mode transponder autonomously switches the telemetry and control system based on the switching command from the radio monitoring device, as follows: (a) When the spacecraft has a high information transmission efficiency requirement, it sends the spread spectrum telemetry and control mission request to the ground through the downlink of the on-demand access telemetry and control system. The ground responds to the request, and then the spacecraft and the ground switch to the spread spectrum telemetry and control system. The spacecraft sends telemetry information to the ground in the normal transmission mode to carry out the telemetry and control mission with a high information transmission rate. After the spread spectrum telemetry and control system mission is completed, the radio listening device sends the on-demand access telemetry and control system switching command to autonomously switch the multi-mode transponder to the on-demand access telemetry and control system and stop the normal transmission mode. (b) When there is a need for high information transmission efficiency on the ground, the uplink signal is sent directly through the spread spectrum telemetry and control system equipment. After receiving the uplink signal, the spacecraft's radio listening device identifies the carrier frequency, occupied bandwidth, Doppler characteristics, and signal energy of the spectrum. If it is determined that the signal characteristics match those of the spread spectrum telemetry and control system used by the spacecraft, the radio listening device sends a spread spectrum telemetry and control system switching command to the multi-mode transponder, which then autonomously switches the multi-mode transponder to the spread spectrum telemetry and control system. The multi-mode transponder then captures and synchronizes the uplink signal and continuously transmits the spread spectrum telemetry and control system signal to the ground, thus completing the spread spectrum telemetry and control system task. When the uplink signal of the spread spectrum telemetry and control system is turned off on the ground, the multi-mode transponder cannot capture the uplink signal, and the radio listening device cannot detect the uplink signal either. In this case, the radio listening device sends an on-demand access telemetry and control system switching command to the multi-mode transponder, which then autonomously switches the multi-mode transponder to the on-demand access telemetry and control system. (c) When there is a high anti-interference telemetry and control requirement on the ground, the uplink signal is directly transmitted through the spread frequency hopping telemetry and control system equipment. After receiving the uplink signal, the spacecraft's radio listening device identifies the carrier frequency, occupied bandwidth, Doppler characteristics, and signal energy of the spectrum. If it is determined that the signal characteristics match those of the spread frequency hopping telemetry and control system used by the spacecraft, the radio listening device sends a spread frequency hopping telemetry and control system switching command to the multi-mode transponder, switching the multi-mode transponder to the spread frequency hopping telemetry and control system. The multi-mode transponder then captures and synchronizes the uplink signal and continuously transmits the spread frequency hopping telemetry and control system signal to the ground, thus completing the spread frequency hopping telemetry and control system task. When the uplink signal of the spread frequency hopping telemetry and control system is turned off on the ground, the multi-mode transponder cannot capture the uplink signal, and the radio listening device cannot detect the uplink signal either. In this case, the radio listening device sends an on-demand access telemetry and control system switching command to the multi-mode transponder, autonomously switching the multi-mode transponder to the on-demand access telemetry and control system.

6. A spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 5, characterized in that: In (b), if the radio eavesdropping device receives an uplink signal but identifies it as not matching the signal characteristics of the spread spectrum telemetry and control system used by the spacecraft, it will not switch the operating mode of the multi-mode transponder. If the radio eavesdropping device identifies the uplink signal as matching the signal characteristics of the spread spectrum telemetry and control system used by the spacecraft and switches the multi-mode transponder to spread spectrum mode, but the multi-mode transponder cannot capture and synchronize the uplink signal after the switch, it will maintain this state and the multi-mode transponder will continue to search and capture. If it still cannot capture and synchronize after 1 minute, the radio eavesdropping device will send an on-demand access telemetry and control system switching command to the multi-mode transponder, and the multi-mode transponder will automatically switch to the on-demand access telemetry and control system.

7. A spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 5, characterized in that: In (c), if the radio eavesdropping device receives an uplink signal but identifies it as not matching the signal characteristics of the spread frequency hopping telemetry and control system used by the spacecraft, it will not switch the operating mode of the multi-mode transponder. If the radio eavesdropping device identifies the uplink signal as matching the signal characteristics of the spread frequency hopping telemetry and control system used by the spacecraft and switches the multi-mode transponder to the spread frequency hopping mode, but the multi-mode transponder cannot capture and synchronize the uplink signal after the switch, it will maintain this state and the multi-mode transponder will continue to search and capture. If it still cannot capture and synchronize after 2 minutes, the radio eavesdropping device will send an on-demand access telemetry and control system switching command to the multi-mode transponder, and the multi-mode transponder will automatically switch to the on-demand access telemetry and control system.

8. A spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 5, characterized in that: In (c), if the radio receiver receives an uplink signal but identifies it as an abnormal spectrum, it is determined that the spacecraft is under telemetry and control interference. At this time, the multi-mode transponder is immediately turned off, and the transmitting section is kept in electromagnetic silence. The radio receiver then continues to monitor the abnormal spectrum. If the abnormal spectrum disappears within 10 minutes, the multi-mode transponder is turned on and restored to the random access telemetry and control system, entering normal working state. If the abnormal spectrum can still be detected after more than 10 minutes, it is considered that the spacecraft has been subjected to targeted interference. The multi-mode transponder is turned on and switched to spread frequency hopping mode, and the transmitter is turned on to send an event report of targeted interference to the ground. If the abnormal spectrum can still be detected after more than 20 minutes, the receiver of the multi-mode transponder is turned on, and the anti-interference capability of the channel is used to wait for the ground to send a spread frequency hopping uplink signal for further processing.

9. A spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 8, characterized in that: If the abnormal spectrum disappears between 10 and 20 minutes, the multi-mode transponder will be restored to the on-demand access telemetry and control system, and the receiver and transmitter of the multi-mode transponder will be restored to operation.

10. A spacecraft autonomous anti-interference telemetry and control system for complex electromagnetic environments according to claim 1, characterized in that: The system is accessible via telemetry and control, using a space-based mode. The uplink carrier uses the F1 frequency point, and the downlink carrier uses the F2 frequency point, both occupying a bandwidth of ±3.5MHz. The spread spectrum telemetry and control system communicates directly with the ground station. The uplink carrier uses the F3 frequency point, and the downlink carrier uses the F4 frequency point, both occupying a bandwidth of ±3.5MHz. The extended frequency hopping telemetry and control system communicates directly with the ground station. The uplink carrier uses the F5 frequency point, and the downlink carrier uses the F6 frequency point, both occupying a bandwidth of ±50MHz.

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