A low-power relay link system that achieves omnidirectional coverage using low-orbit satellites

Abstract

The present application relates to the field of low-orbit satellite communications and discloses a low-power relay link system for achieving omnidirectional coverage on a low-orbit satellite. The system comprises a primary relay measurement and control unit (MTC) and a backup relay measurement and control unit (MTC). Each unit comprises a space antenna, a ground antenna, a radio frequency electronic switch, a duplexer, a low-noise amplifier, a power amplifier (PA), and a baseband processing unit. The system dynamically switches the communication links between the space antenna and the ground antenna using the RF electronic switch to ensure stable two-way communication between the satellite and the relay satellite and the ground station. When the satellite's attitude changes, the system automatically adjusts the antenna link to ensure uninterrupted communication. By adopting a primary-backup dual-machine redundant design, the system can automatically take over communication tasks when the primary relay measurement and control unit fails, thus avoiding communication interruptions caused by equipment failures, ensuring that communication between the satellite, the relay satellite, and the ground station remains unaffected, and improving system reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of low-orbit satellite communications, and in particular to a low-power relay link system that achieves omnidirectional coverage with a low-orbit satellite. Background Art

[0002] Current low-orbit satellite relay link systems typically rely on traditional relay tracking and control schemes, which typically utilize a single space-facing antenna. This configuration simplifies system design and implementation, reducing technical implementation complexity. However, due to the long communication distance between the relay satellite and the low-orbit satellite, systems using a single space-facing antenna often struggle to meet high sensitivity and transmit power requirements. In practical applications, the long communication distance between the low-orbit satellite and the relay satellite makes it difficult for a single-unit system to provide sufficient sensitivity and high equivalent isotropic radiated power (EIRP), thus affecting system performance.

[0003] Furthermore, traditional systems often fail to maintain a stable communication link when a satellite's attitude flips or becomes unstable. Because a single space-pointing antenna can lose its stable connection with the relay satellite during a satellite attitude change, the communication link can be easily interrupted when the satellite's active phase or attitude control becomes unstable. This limitation makes existing low-orbit satellite relay systems unable to effectively guarantee stable and reliable communications during complex missions, especially during satellite attitude flips and other extreme situations.

[0004] Therefore, the existing technology has certain shortcomings when facing the long-distance communication needs between low-orbit satellites and relay satellites, especially when the attitude control is unstable or flips, it is unable to effectively maintain high-quality communication. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a low-power relay link system for low-orbit satellites to achieve omnidirectional coverage, which solves the problem in the existing technology that low-orbit satellites are difficult to maintain a stable communication link during long-distance communication and attitude changes.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A low-power relay link system for achieving omnidirectional coverage of a low-orbit satellite includes a main relay measurement and control unit and a backup relay measurement and control unit, each of which includes:

[0007] Sky antenna and ground antenna are used to communicate with relay satellites and ground stations respectively;

[0008] A radio frequency electronic switch for switching the communication link between the sky antenna and the ground antenna;

[0009] A duplexer is connected to the output of the RF electronic switch to separate the transmit signal from the receive signal;

[0010] a low noise amplifier connected to the receiving port of the duplexer and configured to amplify a received signal;

[0011] a power amplifier connected to the transmit port of the duplexer and configured to amplify the transmit signal;

[0012] The baseband processing unit is connected to the low noise amplifier and the power amplifier respectively, and is used to modulate and demodulate the signal;

[0013] Among them, the main relay measurement and control unit and the backup relay measurement and control unit operate independently, and their radio frequency electronic switches are initially configured as sky antenna and ground antenna respectively before the satellite is launched.

[0014] Preferably, the radio frequency electronic switch is a single-pole double-throw switch, and dynamically switches the links between the sky antenna and the ground antenna through a control signal.

[0015] Preferably, the isolation between the receiving port and the transmitting port of the duplexer is greater than 80 dB, and the operating frequency band covers the S band and the Ka band.

[0016] Preferably, the sky antenna is a right-handed circularly polarized spiral antenna, and the ground antenna is a left-handed circularly polarized patch antenna, and the polarization directions of the two are orthogonal.

[0017] Preferably, the main relay measurement and control unit and the backup relay measurement and control unit are connected to the satellite platform via an A bus and a B bus respectively, and the A bus and the B bus are redundant to each other.

[0018] Preferably, the baseband processing unit supports multiple modulation modes, including QPSK, BPSK and OQPSK, and adaptively selects the modulation mode according to the link quality.

[0019] Preferably, the system further comprises a power management module for dynamically adjusting the output power of the power amplifier and switching the working mode of the primary and standby units according to the power supply status of the satellite platform.

[0020] The present invention also provides a method for achieving omnidirectional coverage of a low-orbit satellite relay link, comprising the following steps:

[0021] Before the satellite is launched, the radio frequency electronic switch of the main relay measurement and control unit is initially configured as a sky-facing antenna, and the radio frequency electronic switch of the backup relay measurement and control unit is initially configured as a ground-facing antenna;

[0022] Real-time monitoring of satellite attitude. When the attitude angle deviation exceeds the preset threshold, the main and standby units switch antenna links.

[0023] A duplexer separates the transmit and receive signals, a low-noise amplifier is used to improve receive sensitivity, and a power amplifier is used to increase transmit EIRP.

[0024] When the main relay measurement and control unit fails, the backup relay measurement and control unit takes over the communication task through the A bus or B bus.

[0025] The present invention provides a low-power relay link system for achieving omnidirectional coverage using low-orbit satellites. It has the following beneficial effects:

[0026] 1. The present invention adopts a master-slave dual-machine redundant design. When the main relay measurement and control unit fails, the backup relay measurement and control unit automatically takes over the communication task, avoiding communication interruption caused by equipment failure, ensuring that the communication between the satellite and the relay satellite and ground station is always unaffected, and improving the reliability of the system.

[0027] 2. The present invention realizes dynamic switching of the sky antenna and the ground antenna through a radio frequency electronic switch, which can cope with satellite attitude flip or other attitude changes, ensuring that the communication link between the satellite and the relay satellite and the ground station is not affected, further improving the communication stability of the satellite during in-orbit operation, and avoiding the risk of communication interruption when the satellite attitude changes in traditional solutions.

[0028] 3. The power management module of the present invention can dynamically adjust the power output according to the working status of the system and the power supply situation of the satellite. In particular, the power adjustment function of the PA can reduce unnecessary power consumption and lower the overall power consumption of the satellite, thereby extending the working time of the satellite and achieving energy-saving effects.

[0029] 4. This invention utilizes a low-noise amplifier and a power amplifier to enhance signal sensitivity at the receiving end and increase the equivalent isotropic radiated power (EIRP) at the transmitting end. This design enhances long-distance communication capabilities between satellites and relay satellites, ensuring signal transmission quality over long distances and in complex environments.

[0030] 5. The baseband processing unit of the present invention supports multiple modulation modes and adaptively selects the optimal modulation mode based on link quality, thereby improving data transmission efficiency and anti-interference capabilities. Under different communication environments, it can automatically adjust the modulation mode to achieve optimal communication performance, ensuring efficient and stable operation of the satellite in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the system architecture of the present invention;

[0032] Figure 2 Schematic diagram of the method of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Please see the attached Figure 1 The present invention provides a low-power relay link system for achieving omnidirectional coverage of low-orbit satellites. The system is configured with a master-standby dual-machine configuration. Each system has the ability to communicate forward and return with the relay satellite, and can ensure the reliability and stability of the relay measurement and control link when the satellite attitude is unstable or flipped.

[0035] The low-orbit satellite relay link system provided by this invention consists of a primary relay measurement and control unit (MTC) and a backup relay measurement and control unit (MTC). These units operate independently. The system's primary purpose is to ensure a stable communication link even when the satellite is unstable or undergoing a rollover, through omnidirectional coverage of both the sky-facing and ground-facing antennas. This design overcomes the shortcomings of traditional relay measurement and control systems, enabling more stable and reliable communication during active phases or when the satellite's attitude is abnormal.

[0036] Each relay measurement and control unit includes:

[0037] Sky antenna: used for communication with relay satellites to ensure high sensitivity and high gain of signal reception and transmission.

[0038] Ground antenna: used to communicate with the ground station and supports two-way transmission.

[0039] RF electronic switch: used to switch the signal link between the sky antenna and the ground antenna.

[0040] Duplexer: Effectively isolates the receive and transmit signals to ensure that the transmit signal does not interfere with the receive signal.

[0041] Low noise amplifier (LNA): amplifies the received weak signal and improves the system's receiving sensitivity.

[0042] Power amplifier (PA): Increases the power of transmitted signals to ensure long-distance communication between satellites and relay satellites.

[0043] Baseband processing unit: modulates and demodulates signals and supports multiple modulation methods (such as QPSK, BPSK, and OQPSK).

[0044] The main and standby relay measurement and control units are connected to the satellite platform through A bus and B bus respectively. The two buses are redundant to ensure high availability of the system.

[0045] Each relay tracking and control unit uses an RF electronic switch to flexibly switch the communication link between the space antenna and the ground antenna. Before launch, the RF electronic switch of the primary relay tracking and control unit is connected to the space antenna, while the RF electronic switch of the backup relay tracking and control unit is connected to the ground antenna. This allows the system to maintain a stable communication link with the relay satellite and ground station even if the satellite experiences an attitude flip or instability in orbit, preventing communication interruptions caused by attitude changes.

[0046] like Figure 1 As shown, in this embodiment, the RF electronic switch is used to switch the signal link between the space antenna and the ground antenna, ensuring stable signal transmission in different operating states of the satellite system, whether communicating with relay satellites or ground stations. Specifically, the RF electronic switch acts as a single-pole double-throw switch, dynamically switching between the two antennas through control signals.

[0047] Before launch, the primary relay tracking and control unit's RF electronic switch is connected to the space antenna, while the backup relay tracking and control unit's RF electronic switch is connected to the ground antenna. At this point, the communication link between the satellite and the relay satellite is established via the space antenna, while communication between the ground station and the satellite is conducted via the ground antenna. If the satellite experiences an attitude rollover or is not fully stable, the system relies on the RF electronic switch to dynamically switch antenna links to ensure uninterrupted signal transmission.

[0048] For example, if a satellite's attitude flips or otherwise changes, an RF electronic switch can respond to a control signal and switch the signal link from the space-facing antenna to the ground-facing antenna, or vice versa. This switching is performed based on the satellite's real-time status. The RF electronic switch's operation must not only account for changes in the satellite's attitude but also prevent interruptions in the communication link when the attitude is unstable. By controlling the switch's operation, the system ensures that the communication link remains uninterrupted, adapting and adjusting promptly based on signal strength and quality.

[0049] RF electronic switches require high switching speeds. In some scenarios, the switching process must be completed in a short time to prevent communication loss or interruption. For example, if the satellite's attitude changes dramatically during operation, the RF electronic switch must be able to respond to the satellite's attitude change and complete the switch in an extremely short time (less than 10ms) to ensure an uninterrupted signal link.

[0050] Furthermore, the RF electronic switch can adapt to the needs of different operating modes, such as the changing operating status of a satellite in different orbital segments and operating phases. Through this dynamic switching mechanism, the RF electronic switch design enables the system to operate efficiently even in complex environments. In particular, when the satellite's attitude is unstable or it moves into a special orbit, the RF electronic switch can quickly switch the antenna link, avoiding the risk of signal loss.

[0051] This RF electronic switch features a low-power design and low loss, typically less than 1dB. Compared to traditional microwave network designs, the use of RF electronic switches significantly reduces link loss, lowers the transmit power requirements of the power amplifier, and ensures overall system efficiency and performance. The RF electronic switch design further optimizes the communication link between low-orbit satellites and relay satellites, reducing the 3.5dB loss commonly seen in microwave networks. This improves the system's G / T performance and meets more stringent communication performance requirements.

[0052] It's important to note that in actual satellite applications, RF electronic switches rely on more than just a single control signal. To adapt to diverse and complex operating environments, the system incorporates an intelligent control module. By monitoring the satellite's attitude and communication link quality in real time, the RF electronic switch control signal is adjusted accordingly, enabling more precise switching control. This feature ensures that the system automatically optimizes link configuration based on real-time changes in the satellite platform's power supply status, communication environment, and satellite attitude, further improving system reliability and stability.

[0053] like Figure 1 As shown in this embodiment, the low-noise amplifier (LNA) and power amplifier (PA) play a key role in the low-orbit satellite omnidirectional coverage, low-power relay link system of the present invention. They are responsible for amplifying weak received signals and increasing the power of transmitted signals, respectively. The design and operating mechanism of the LNA and PA are intended to improve the system's communication quality and ensure signal stability over long-distance transmission.

[0054] First, a low-noise amplifier (LNA) is connected to the duplexer's receive port. Its primary task is to amplify weak signals received from relay satellites or ground stations. Due to the long distance between low-Earth orbit satellites and relay satellites, the received signals are often weak, making the LNA's sensitivity and noise figure particularly critical. In this embodiment, the LNA features a low noise figure, thereby maximizing signal quality and minimizing system noise. Specifically, the LNA precisely amplifies the signal, ensuring that the received signal maintains a sufficient signal-to-noise ratio during subsequent processing stages.

[0055] For example, LNA effectively improves the receiving performance of the entire system by reducing the amplification effect of noise, so that even when there is a long communication distance or strong interference between the low-orbit satellite and the relay satellite, the quality of the received signal can still meet the transmission requirements.

[0056] Next, the power amplifier (PA) connects to the duplexer's transmit port. It's primarily responsible for boosting the signal's transmit power to overcome signal attenuation caused by the distance between the satellite and the relay satellite. Signals between the satellite and relay satellite are attenuated by the atmosphere and the space environment, making the PA's function crucial. By effectively boosting the transmitted signal's power, the PA ensures a stable communication link between the satellite and relay satellite.

[0057] In this embodiment, the PA design takes into account the balance between power requirements and system power consumption. Given the high energy efficiency requirements of low-orbit satellites, the PA employs an optimized power management design to maximize signal transmission power while minimizing power consumption. The PA's output power is designed to meet the high power requirements of long-distance transmission without causing excessive system energy consumption.

[0058] For example, when transmitting signals, the PA can dynamically adjust its output power based on link quality to accommodate different communication environments. For example, in good communication link conditions, the PA can reduce power output to lower energy consumption; whereas in environments with significant signal attenuation, the PA can provide higher transmit power to ensure communication reliability.

[0059] The collaborative work of the LNA and PA ensures efficient signal transmission during both reception and transmission in low-orbit satellite systems. On the receiving end, the LNA amplifies weak signals while maintaining low noise levels, enabling the received signal to pass through subsequent processing stages. On the transmitting end, the PA provides sufficient transmit power to prevent excessive signal attenuation during long-distance transmission.

[0060] Furthermore, the LNA and PA designs also take into account adaptability to frequency range and operating environment. Both the LNA and PA in this embodiment support a wide range of system operating frequency bands, particularly within the S-band and Ka-band operating ranges, ensuring efficient signal processing across multiple frequency bands.

[0061] like Figure 1As shown, in this embodiment, a duplexer is used to effectively isolate the transmit and receive signals in the satellite system, ensuring that the transmit signal does not interfere with the receive signal. The duplexer is a key component connected to the output of the RF electronic switch and plays a vital role in the signal path of the entire system. Specifically, the duplexer separates the signal received from a satellite or relay satellite from the signal transmitted from the satellite, thereby enabling independent transmission of the transmit and receive signals.

[0062] In this embodiment, the duplexer design requires high isolation, typically requiring greater than 80 dB between the receiving port and the transmitting port. This high isolation ensures that the transmitted signal does not interfere with the received signal, preventing mutual signal influence and thus improving the stability of the communication link. Specifically, by using appropriate filtering techniques and materials, the duplexer can effectively isolate the two signal channels, ensuring that the signal in each channel is clear and free from interference from other signals.

[0063] For example, during satellite communications, when signals are transmitted from a low-orbit satellite to a relay satellite, a duplexer ensures that the strength of the transmitted signal does not affect the received signal. For example, in communications between a satellite and a ground station, a duplexer ensures that the satellite's transmitted signal does not interfere with the feedback signal received from the ground station. This allows the system to transmit and receive simultaneously without signal conflicts, ensuring efficient and stable communications.

[0064] Furthermore, the duplexer in this embodiment supports a wide operating frequency band, covering the S-band and Ka-band. The S-band and Ka-band are commonly used satellite communication frequency bands, offering excellent signal penetration and spectrum resources. The duplexer is designed to cover these frequency bands to accommodate communication needs in different frequency bands, ensuring that the satellite system can flexibly adapt to diverse communication environments. Specifically, the duplexer's wideband characteristics enable the system to operate stably across multiple frequency bands, without being restricted by frequency fluctuations.

[0065] like Figure 1 As shown, in this embodiment, the baseband processing unit is responsible for signal modulation and demodulation in the low-orbit satellite omnidirectional coverage, low-power relay link system, ensuring efficient data transmission. The baseband processing unit is designed not only to support multiple modulation methods but also to adaptively select the optimal modulation method based on the link quality, thereby improving the system's transmission efficiency and communication quality.

[0066] In a specific implementation, the baseband processing unit is connected to a low-noise amplifier (LNA) and a power amplifier (PA). The received signal is amplified by the LNA and then sent to the baseband processing unit for demodulation. The demodulated signal is further processed to recover the original data. The transmit signal is modulated by the baseband processing unit and sent to the PA for power amplification and transmission. During this process, the baseband processing unit ensures that all signals conform to the required modulation standards and communication protocols.

[0067] For example, in practical applications, the baseband processing unit can support multiple modulation schemes, including QPSK (Quadrature Phase Shift Keying), BPSK (Binary Phase Shift Keying), and OQPSK (Offset Quadrature Phase Shift Keying). Based on the actual link conditions, the baseband processing unit can dynamically select the most appropriate modulation scheme. For example, when the link quality is good, the baseband processing unit may select QPSK to increase the data transmission rate; however, when the link quality is poor or interference is high, the baseband processing unit may select BPSK to improve the signal's anti-interference ability.

[0068] Furthermore, the baseband processing unit's adaptive modulation capabilities enable the system to maintain efficient communication performance under varying operating conditions. During communications between satellites and relay satellites, or between satellites and ground stations, link quality can be affected by various factors, such as distance, weather conditions, and interference. The baseband processing unit monitors these conditions in real time and selects the appropriate modulation method based on parameters such as signal strength and noise, ensuring reliable signal transmission.

[0069] The baseband processing unit in this embodiment also supports a link quality feedback mechanism. When signal quality changes, the baseband processing unit can adjust its modulation scheme based on the feedback signal to avoid data loss or errors caused by signal attenuation or interference. This mechanism enables the satellite communication system to adaptively adjust in changing operating environments, ensuring stable and reliable communication.

[0070] For example, when the signal on a communication link between a satellite and a relay satellite experiences significant attenuation or noise, the baseband processing unit can automatically switch to a lower-rate modulation mode (such as BPSK) to ensure stable signal transmission. Conversely, when the signal link quality is good, the baseband processing unit will select a more efficient modulation method (such as QPSK) to increase the data transmission rate.

[0071] In a preferred embodiment, the system of the present invention further includes a power management module for dynamically adjusting the output power of the power amplifier and switching the working mode of the main and standby units according to the power supply status of the satellite platform.

[0072] In this embodiment, the power management module plays a crucial role in the low-orbit satellite omnidirectional coverage, low-power relay link system of the present invention. This module is responsible for managing and regulating the power of the entire system, ensuring efficient and stable operation under different operating conditions. The design of the power management module takes into account the power supply conditions of the satellite platform and dynamically adjusts power output according to different operating modes, ensuring that the power requirements of each component are met during operation while achieving energy savings.

[0073] In this embodiment, the power management module closely coordinates with the operating status of the power amplifier (PA) and other key components. When signal transmission between the satellite and a relay satellite or ground station requires higher transmit power, the power management module increases the PA's output power to ensure efficient transmission of communication signals. When signal quality is good or the link is stable, the power management module reduces power output to avoid unnecessary power consumption.

[0074] Exemplarily, the power management module can automatically select an appropriate power level based on link quality by adjusting the PA's output power. For example, when the satellite is in good communication condition, the power management module may reduce the PA's output power to reduce the satellite's total power consumption. Conversely, in situations of signal attenuation or high noise levels, the power management module automatically increases the PA's output power to ensure that the signal can overcome attenuation during long-distance transmission and maintain communication quality.

[0075] The power management module is also associated with the switching of operating modes between the primary and backup relay TT&C units. During normal satellite operation, the power management module dynamically selects the operating state of the primary or backup relay TT&C unit based on the satellite platform's power supply status. If the system detects that the primary relay TT&C unit's power consumption is approaching its upper limit, the power management module switches to the backup relay TT&C unit, ensuring that power consumption does not exceed the system's total power limit. This not only optimizes the satellite's energy efficiency but also ensures system reliability during operation.

[0076] In addition, the power management module in this embodiment also features battery charge monitoring and power optimization. By real-time monitoring of the battery charge and the power consumption of each component, the module can rationally allocate system resources based on the current power supply situation. When the battery charge is low, the module automatically adjusts power output to prioritize critical tasks while limiting the power consumption of non-critical components, thereby extending the satellite's operating time.

[0077] For example, when the battery charge is low, the power management module conserves energy by reducing power output, switching to low-power mode, or shutting down some non-critical systems. This allows the satellite to maintain basic communication functions even when the battery is low until external power is restored.

[0078] Another important function of the power management module is to support fault diagnosis and self-recovery mechanisms. When the system's power status is abnormal, the power management module can detect the fault and issue a timely alarm. At the same time, the control system switches to a backup power source or adjusts power distribution to ensure continued satellite operation and maintain the stability of the communication link.

[0079] In summary, the present invention uses radio frequency electronic switches to dynamically switch between the sky-facing and ground-facing antennas, ensuring stable two-way communication with relay satellites and ground stations even when the satellite's attitude changes or becomes unstable. The system includes key components such as a low-noise amplifier, power amplifier, duplexer, and baseband processing unit. It supports multiple modulation schemes and adaptively selects the modulation mode based on link quality. A power management module optimizes power output and adjusts operating modes, improving system energy efficiency and reliability. This solution can meet the high-sensitivity, high-EIRP communication requirements between low-orbit satellites and relay satellites, while maintaining low power consumption and enhanced system stability.

[0080] Please see the attached Figure 2 The present invention also provides a method for achieving omnidirectional coverage of a low-orbit satellite relay link, comprising the following steps:

[0081] S1. Before the satellite is launched, the RF electronic switch of the main relay measurement and control unit is initially configured as a sky-facing antenna, and the RF electronic switch of the backup relay measurement and control unit is initially configured as a ground-facing antenna;

[0082] First, before the satellite is launched, the system performs an initial configuration of the RF electronic switches of the primary and backup relay TT&C units. The primary relay TT&C unit's RF electronic switch is connected to the sky antenna, responsible for communicating with the relay satellite; while the backup relay TT&C unit's RF electronic switch is connected to the ground antenna, used for communicating with the ground station.

[0083] S2: Real-time monitoring of satellite attitude. When the attitude angle deviation exceeds the preset threshold, the main and standby units switch antenna links.

[0084] During satellite operation, the system monitors the satellite's attitude in real time. If the satellite's attitude angle deviation exceeds a preset threshold, the primary and backup relay measurement and control units automatically switch antenna links. For example, if the satellite's attitude flips or undergoes a significant angular change, the RF electronic switch automatically switches to the appropriate antenna to ensure a stable communication link.

[0085] S3, using a duplexer to separate the transmit and receive signals, using a low-noise amplifier to improve receive sensitivity, and using a power amplifier to increase transmit EIRP;

[0086] Furthermore, the system uses a duplexer to separate transmit and receive signals, ensuring that transmitted and received signals do not interfere with each other. When receiving signals, a low-noise amplifier improves the sensitivity of the received signal, ensuring distortion-free transmission over long distances. When transmitting signals, a power amplifier boosts the signal's transmit power, increasing the equivalent isotropic radiated power (EIRP) to overcome signal attenuation during long-distance transmission.

[0087] S4. When the main relay measurement and control unit fails, the backup relay measurement and control unit takes over the communication task via the A bus or the B bus;

[0088] Finally, when the main relay measurement and control unit fails due to a fault or other reasons, the backup relay measurement and control unit will automatically take over the communication task through the A bus or B bus, ensuring that the satellite system can maintain a stable communication link under any circumstances without being affected by interruptions.

[0089] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A low-power relay link system for achieving omnidirectional coverage using a low-orbit satellite, characterized in that: It includes a main relay measurement and control unit and a backup relay measurement and control unit, and the main relay measurement and control unit and the backup relay measurement and control unit each include: Sky antenna and ground antenna are used to communicate with relay satellites and ground stations respectively; A radio frequency electronic switch for switching the communication link between the sky antenna and the ground antenna; A duplexer is connected to the output of the RF electronic switch to separate the transmit signal from the receive signal; a low noise amplifier connected to the receiving port of the duplexer and configured to amplify a received signal; a power amplifier connected to the transmit port of the duplexer and configured to amplify the transmit signal; The baseband processing unit is connected to the low noise amplifier and the power amplifier respectively, and is used to modulate and demodulate the signal; The main relay measurement and control unit and the backup relay measurement and control unit operate independently, and their radio frequency electronic switches are initially configured as space antennas and ground antennas respectively before the satellite is launched; The radio frequency electronic switch is a single-pole double-throw switch, and dynamically switches the links between the sky antenna and the ground antenna through a control signal; Before the satellite is launched, the radio frequency electronic switch of the main relay measurement and control unit is initially configured as a sky-facing antenna, and the radio frequency electronic switch of the backup relay measurement and control unit is initially configured as a ground-facing antenna; The satellite attitude is monitored in real time. When the attitude angle deviation exceeds the preset threshold, the main and standby units switch the antenna links.

2. The low-power relay link system for achieving omnidirectional coverage using a low-orbit satellite according to claim 1, characterized in that: The isolation between the receiving port and the transmitting port of the duplexer is greater than 80dB, and the operating frequency band covers the S band and the Ka band.

3. The low-power relay link system for achieving omnidirectional coverage using a low-orbit satellite according to claim 1, characterized in that: The sky-facing antenna is a right-hand circularly polarized spiral antenna, and the ground-facing antenna is a left-hand circularly polarized patch antenna, and the polarization directions of the two are orthogonal.

4. The low-power relay link system for achieving omnidirectional coverage using a low-orbit satellite according to claim 1, characterized in that: The main relay measurement and control unit and the backup relay measurement and control unit are connected to the satellite platform via an A bus and a B bus respectively, and the A bus and the B bus are redundant to each other.

5. The low-power relay link system for achieving omnidirectional coverage using a low-orbit satellite according to claim 1, characterized in that: The baseband processing unit supports multiple modulation modes, including QPSK, BPSK and OQPSK, and adaptively selects the modulation mode according to the link quality.

6. The low-power relay link system for achieving omnidirectional coverage using a low-orbit satellite according to claim 1, characterized in that: The system also includes a power management module for dynamically adjusting the output power of the power amplifier and switching the working mode of the main and standby units according to the power supply status of the satellite platform.

7. A method for achieving omnidirectional coverage of a low-orbit satellite relay link, according to any one of claims 1 to 6, wherein the low-power relay link system for achieving omnidirectional coverage of a low-orbit satellite is characterized in that: The following steps are involved: Before the satellite is launched, the radio frequency electronic switch of the main relay measurement and control unit is initially configured as a sky-facing antenna, and the radio frequency electronic switch of the backup relay measurement and control unit is initially configured as a ground-facing antenna; Real-time monitoring of satellite attitude. When the attitude angle deviation exceeds the preset threshold, the main and standby units switch antenna links. A duplexer separates the transmit and receive signals, a low-noise amplifier is used to improve receive sensitivity, and a power amplifier is used to increase transmit EIRP. When the main relay measurement and control unit fails, the backup relay measurement and control unit takes over the communication task through the A bus or B bus.

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