阅读说明：本技术 一种支持ssa、sma链路的星载中继用户终端 (Satellite-borne relay user terminal supporting SSA and SMA links ) 是由 张伟 王永 董爱华 张�浩 康峰源 王晓东 王春霞 于常永 蒋海涛 于 2020-12-07 设计创作，主要内容包括：本发明公开一种支持SSA、SMA链路的星载中继用户终端,包括收发处理模块、宽波束天线模块和相控阵天线模块,各模块之间通过高频电缆和低频电缆连接；收发处理模块,接收SSA、SMA链路的前向遥控射频信号,处理形成前向遥控中频信号,进行捕获、跟踪、解调处理,解调出遥控数据送至航天器平台；接收来自于航天器平台的返向遥测信息,进行编码、扩频、调制处理后进行变频发射；通过总线接口接收航天器轨道、姿态信息,结合中继星轨道实时完成波束指向角计算；宽波束天线模块发送SSA、SMA链路的前向遥控射频信号至收发处理模块；相控阵天线模块,接收收发处理模块提供的射频信号和控制信号,完成链路射频信号的功率放大和空间波束合成与指向控制。(The invention discloses a satellite-borne relay user terminal supporting SSA and SMA links, which comprises a receiving and transmitting processing module, a wide beam antenna module and a phased array antenna module, wherein the modules are connected through a high-frequency cable and a low-frequency cable; the receiving and transmitting processing module receives the forward remote control radio frequency signals of the SSA and SMA links, processes the signals to form forward remote control intermediate frequency signals, performs capturing, tracking and demodulation processing on the signals, demodulates remote control data and sends the demodulated remote control data to the spacecraft platform; receiving return telemetering information from a spacecraft platform, and performing coding, spread spectrum and modulation processing and then performing variable frequency transmission; receiving orbit and attitude information of the spacecraft through a bus interface, and finishing beam pointing angle calculation in real time by combining a relay satellite orbit; the wide beam antenna module sends forward remote control radio frequency signals of the SSA and SMA links to the receiving and sending processing module; and the phased array antenna module receives the radio frequency signal and the control signal provided by the transceiving processing module, and completes the power amplification of the link radio frequency signal and the spatial beam synthesis and pointing control.)

1. A satellite-borne relay user terminal supporting SSA and SMA links is characterized by comprising a receiving and transmitting processing module, a wide beam antenna module and a phased array antenna module, wherein the modules are connected through a high-frequency cable and a low-frequency cable; the receiving and transmitting processing module comprises a baseband module, a radio frequency receiving and transmitting module and a beam pointing angle analysis module;

a baseband module: receiving forward remote control radio frequency signals of the SSA and SMA links, processing the signals to form forward remote control intermediate frequency signals, performing capturing, tracking and demodulation processing on the signals, demodulating remote control data and sending the demodulated remote control data to a spacecraft platform;

the radio frequency transceiving module: receiving return telemetering information from a spacecraft platform, and performing coding, spread spectrum and modulation processing and then performing variable frequency transmission;

beam pointing angle analysis module: receiving orbit and attitude information of the spacecraft through a bus interface, and finishing beam pointing angle calculation in real time by combining a relay satellite orbit;

the wide beam antenna module sends forward remote control radio frequency signals of the SSA and SMA links to the receiving and sending processing module;

and the phased array antenna module receives the radio frequency signal and the control signal provided by the transceiving processing module, and completes the power amplification of the link radio frequency signal and the spatial beam synthesis and pointing control.

2. The SSA, SMA link supporting satellite borne relay user terminal of claim 1, characterized in that: the wide beam antenna module adopts a double-winding back-radiation spiral antenna mode, the double-wire spiral line is arranged on the outer surface of the conical antenna supporting tube, and the phase difference of feeding points is 180 degrees.

3. The SSA, SMA link supporting satellite borne relay user terminal of claim 1, characterized in that: when the beam pointing angle analysis module completes the calculation of the beam pointing angle, the specific principle is as follows:

(1) firstly, preprocessing a satellite orbit: the method comprises the steps of low-orbit satellite orbit preprocessing and relay satellite orbit preprocessing;

(2) under the geocentric inertial coordinate system, calculating a position vector of the low-orbit satellite pointing to the relay satellite;

(3) converting the position vector of the low-orbit satellite pointing to the relay satellite into a low-orbit satellite mass center orbit coordinate system from a geocentric inertial coordinate system to be expressed;

(4) converting a position vector of the low-orbit satellite pointing to the relay satellite into a low-orbit satellite body coordinate system from a low-orbit satellite mass center orbit coordinate system for representation;

(5) and finally, calculating the pitch angle and the azimuth angle pointed by the wave beam of the phased array antenna in the phased array antenna coordinate system according to the geometric relation.

4. The SSA, SMA link supporting satellite borne relay user terminal of claim 1, characterized in that: the radio frequency transceiver module realizes identification of SSA and SMA links and autonomously realizes transmission of a return link, and the specific principle is as follows:

(1) generating 2 channels and 4 paths of local orthogonal carriers with different frequency points aiming at an SSA mode and an SMA mode;

(2) externally input AD sampling signals are respectively mixed with 2-channel local carriers;

(3) generating a replica pseudo-random code driven by a code clock based on a pseudo-code generator;

(4)4 paths of mixing signals are respectively related to the copied pseudo random codes for despreading;

(5) respectively accumulating, combining and caching the data subjected to the 2-channel orthogonal correlation processing;

(6) performing fast FFT (fast Fourier transform) on the 2-channel data in a time-sharing manner to obtain a square sum after transformation;

(7) judging whether the 2-path square sum maximum value exceeds a preset threshold or not, and acquiring a signal;

(8) determining a current working link mode and generating a link working mode;

(9) and switching the working frequency point of the return link according to the mode.

Technical Field

The invention relates to the technical field of satellite communication, in particular to a satellite-borne relay user terminal supporting SSA and SMA links.

Background

With the development of the space-based measurement and control technology, the relay user terminal is widely applied to the low-orbit satellite. At present, the first generation relay satellite system only has an SSA link, the second generation relay satellite system includes an SMA link in addition to the SSA link, and the SSA link and the SMA link correspond to different forward remote control radio frequency signals and return remote control radio frequency signals. In addition, system indexes such as Equivalent Isotropic Radiated Power (EIRP) and received G/T value of a second generation relay satellite system are changed relative to a first generation relay satellite system, particularly, the EIRP value and the G/T value are lower in an SMA link, and space-based measurement and control communication between a low-orbit satellite and the relay satellite cannot be realized by adopting hardware configuration of a first generation relay terminal.

The traditional relay user terminal consists of a signal processing module and two measurement and control antennas (one antenna receives and transmits), wherein the signal processing module internally comprises a 10W power amplifier unit, the receiving antenna adopts a left-hand circular polarization form, and the transmitting antenna adopts a right-hand circular polarization form. The configuration meets the measurement and control requirements of the SSA link of the first generation relay satellite and cannot be compatible with two links of the SSA and the SMA of the second generation relay satellite.

In order to realize space-based measurement and control of SSA and SMA links of a second-generation relay satellite system and meet measurement and control requirements of SSA links of a plurality of on-orbit first-generation relay satellites, a satellite-borne relay user terminal compatible with the SSA and SMA links is designed to meet measurement and control communication of the first-generation and second-generation relay satellites, and therefore space-based measurement and control can play greater effects.

Disclosure of Invention

The invention provides a satellite-borne relay user terminal supporting SSA and SMA links, which is compatible with the two links of SSA and SMA and can establish a space-based measurement and control link with a first-generation relay satellite system and a second-generation relay satellite system so as to realize the integrated design of two working modes.

The invention is realized by adopting the following technical scheme: a satellite-borne relay user terminal supporting SSA and SMA links comprises a receiving and transmitting processing module, a wide beam antenna module and a phased array antenna module, wherein the modules are connected through a high-frequency cable and a low-frequency cable; the receiving and transmitting processing module comprises a baseband module, a radio frequency receiving and transmitting module and a beam pointing angle analysis module;

a baseband module: receiving forward remote control radio frequency signals of the SSA and SMA links, processing the signals to form forward remote control intermediate frequency signals, performing capturing, tracking and demodulation processing on the signals, demodulating remote control data and sending the demodulated remote control data to a spacecraft platform;

the radio frequency transceiving module: receiving return telemetering information from a spacecraft platform, and performing coding, spread spectrum and modulation processing and then performing variable frequency transmission;

beam pointing angle analysis module: receiving orbit and attitude information of the spacecraft through a bus interface, and finishing beam pointing angle calculation in real time by combining a relay satellite orbit;

the wide beam antenna module sends forward remote control radio frequency signals of the SSA and SMA links to the receiving and sending processing module;

and the phased array antenna module receives the radio frequency signal and the control signal provided by the transceiving processing module, and completes the power amplification of the link radio frequency signal and the spatial beam synthesis and pointing control.

Furthermore, the wide-beam antenna module adopts a form of a double-winding back-radiation helical antenna, the double-wire helical line is arranged on the outer surface of the conical antenna supporting tube, the phase difference of the feed points is 180 degrees, and the wide coverage range and the large antenna gain are met by adjusting the helical diameter, the thread pitch and the thread pitch angle of the antenna.

Further, when the beam pointing angle analysis module completes the calculation of the beam pointing angle, the specific principle is as follows:

(1) firstly, preprocessing a satellite orbit: the method comprises low-orbit satellite orbit preprocessing and relay satellite orbit preprocessing, so that orbit information provided by a satellite is converted into a position vector under an inertial coordinate system;

(2) under the geocentric inertial coordinate system, calculating a position vector of the low-orbit satellite pointing to the relay satellite;

(3) converting the position vector of the low-orbit satellite pointing to the relay satellite into a low-orbit satellite mass center orbit coordinate system from a geocentric inertial coordinate system to be expressed;

(4) converting a position vector of the low-orbit satellite pointing to the relay satellite into a low-orbit satellite body coordinate system from a low-orbit satellite mass center orbit coordinate system for representation;

(5) and finally, calculating the pitch angle and the azimuth angle pointed by the wave beam of the phased array antenna in the phased array antenna coordinate system according to the geometric relation.

Furthermore, the radio frequency transceiver module realizes identification of the SSA link and the SMA link, and can ensure that the receiver autonomously realizes transmission of the return link by self-identifying a link mode and switching a working mode of the return link according to a capturing condition of a signal received by a current forward link in the SSA link and the SMA link, and the specific principle is as follows:

(1) generating 2 channels and 4 paths of local orthogonal carriers with different frequency points aiming at an SSA mode and an SMA mode;

(2) externally input AD sampling signals are respectively mixed with 2-channel local carriers;

(3) generating a replica pseudo-random code driven by a code clock based on a pseudo-code generator;

(4)4 paths of mixing signals are respectively related to the copied pseudo random codes for despreading;

(5) respectively accumulating, combining and caching the data subjected to the 2-channel orthogonal correlation processing;

(6) performing fast FFT (fast Fourier transform) on the 2-channel data in a time-sharing manner to obtain a square sum after transformation;

(7) judging whether the 2-path square sum maximum value exceeds a preset threshold or not, and acquiring a signal;

(8) determining a current working link mode and generating a link working mode;

(9) and switching the working frequency point of the return link according to the mode.

Compared with the prior art, the invention has the advantages and positive effects that:

1. the wide-beam antenna module and the phased-array antenna module are designed, the problem of wide-beam coverage of the relay satellite is solved by combining a low-gain S-band passive wide-beam antenna and a high-gain S-band active phased-array antenna, and the requirements of large-range high-reliability key remote control information receiving and wide-angle remote control information continuous tracking and transmitting are met;

2. combining the calculation of the beam pointing angle of the phased array antenna, simplifying the calculation of the pointing angle and finishing the rapid calculation of the beam pointing angle of the phased array antenna on the premise that satellite resources are limited and the pointing accuracy requirement is met; by combining the phased array antenna, the pointing angle of the phased array antenna can be calculated in real time only by receiving satellite orbit information in real time and injecting relay satellite orbit information, so that the compatibility is better;

3. in addition, according to the scheme, the link working mode can be adaptively changed without externally sending a mode switching instruction to auxiliary information after the link is identified or a ground, and the working mode of the return link is switched. The phenomenon of mode switching abnormity under the abnormal conditions of instruction receiving error, ground instruction sending failure, auxiliary information error and the like is avoided, and the self-adaptive capacity of a receiver is improved; the integrated diversified design concept of the current equipment is met, and the integrated diversified design method has the advantages of being simple in design, high in reliability and the like.

Drawings

Fig. 1 is a block diagram of a satellite-borne relay user terminal supporting SSA and SMA links according to an embodiment of the present invention;

fig. 2 is a schematic diagram illustrating a principle of beam pointing angle calculation according to an embodiment of the present invention;

fig. 3 is a schematic diagram illustrating an identification principle of the SSA and SMA links according to the embodiment of the present invention.

Detailed Description

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be further described with reference to the accompanying drawings and examples. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those described herein, and thus, the present invention is not limited to the specific embodiments disclosed below.

In an embodiment, a satellite-borne relay user terminal supporting SSA and SMA links, as shown in fig. 1, includes a transceiving processing module, a wide beam antenna module, and a phased array antenna module, where each module is connected with each other through a high frequency cable and a low frequency cable;

the receiving and transmitting processing module comprises a baseband module, a radio frequency receiving and transmitting module and a beam pointing angle analysis module;

a baseband module: receiving forward remote control radio frequency signals of the SSA and SMA links, processing the signals to form forward remote control intermediate frequency signals, performing capturing, tracking and demodulation processing on the signals, demodulating remote control data and sending the demodulated remote control data to a spacecraft platform;

the radio frequency transceiving module: receiving return telemetering information from a spacecraft platform, and performing coding, spread spectrum and modulation processing and then performing variable frequency transmission;

beam pointing angle analysis module: receiving orbit and attitude information of the spacecraft through a bus interface, and finishing beam pointing angle calculation in real time by combining a relay satellite orbit;

the wide beam antenna module sends forward remote control radio frequency signals of the SSA and SMA links to the receiving and sending processing module, a double-winding back-radiation spiral antenna form is adopted, a double-wire spiral line is arranged on the outer surface of the conical antenna supporting tube, the phase difference of a feed point is 180 degrees, and a wider coverage range and larger antenna gain are met by adjusting the spiral diameter, the thread pitch and the thread pitch angle of the antenna;

and the phased array antenna module receives the radio frequency signal and the control signal provided by the transceiving processing module, completes power amplification and space beam forming and pointing control of the link radio frequency signal, and tracks the appointed relay satellite by a program.

The receiving and transmitting processing module further comprises a power module and an interface module; the power supply module is configured for connecting a primary power supply provided by the spacecraft platform, converting the primary power supply into a secondary power supply and supplying power to the interface module, the baseband module, the radio frequency transceiver module and the like; the interface module is configured to receive the indirect instruction and the spacecraft orbit parameter information through a CAN bus or a 1553B bus and send the working state remote sensing information of the relay user terminal to the spacecraft platform; the device is also configured to send the beam pointing angle calculated by the beam pointing angle analysis module to the phased array antenna through a serial port and receive the telemetering state information of the phased array antenna; further configured to output the OC command to the phased array antenna; in addition, the radio frequency transceiver module is configured to receive the forward remote control radio frequency signals of the SSA and SMA links, process the signals to form forward remote control intermediate frequency signals and send the signals to the baseband module; the system is also configured to carry out frequency conversion transmission on the zero intermediate frequency signal telemetering signal provided by the baseband module; the baseband module is also configured to receive the return telemetering information from the spacecraft platform, perform framing, encoding and spectrum spreading to obtain a zero intermediate frequency telemetering signal, and send the zero intermediate frequency telemetering signal to the radio frequency transceiving module; and anti-interference processing software is also configured, so that the narrow-band interference resistance of the relay user terminal is improved.

The wide-beam antenna module and the phased-array antenna module are designed, the problem of wide-beam coverage of the relay satellite is solved by combining the low-gain S-band passive wide-beam antenna with the high-gain S-band active phased-array antenna, and the requirements of large-range high-reliability key remote control information receiving and wide-angle remote control information continuous tracking and transmitting are met.

It should be emphasized that, when the beam pointing angle analysis module completes the calculation of the beam pointing angle, the transceiver processing module can be compatible with two orbit calculation modes, and it is ensured that, under the minimum resource utilization rate, the pointing angle information of the satellite phased array antenna pointing to the relay satellite is calculated according to the orbit information of the satellite (J2000 orbit information or WGS84 orbit information), and the calculation of the beam pointing angle of the phased array antenna is quickly realized by the beam pointing angle analysis module, and the specific principle is as follows:

(1) firstly, preprocessing a satellite orbit: the method comprises low-orbit satellite orbit preprocessing and relay satellite orbit preprocessing, so that orbit information provided by a satellite is converted into a position vector under an inertial coordinate system; (2) under the geocentric inertial coordinate system, calculating a position vector of the low-orbit satellite pointing to the relay satellite; (3) converting the position vector of the low-orbit satellite pointing to the relay satellite into a low-orbit satellite mass center orbit coordinate system from a geocentric inertial coordinate system to be expressed; (4) converting a position vector of the low-orbit satellite pointing to the relay satellite into a low-orbit satellite body coordinate system from a low-orbit satellite mass center orbit coordinate system for representation; (5) and finally, calculating the pitch angle and the azimuth angle pointed by the wave beam of the phased array antenna in the phased array antenna coordinate system according to the geometric relation.

On the premise that on-board resources are limited and the pointing accuracy requirement is met, the rapid calculation of the phased array antenna beam pointing angle is completed by using a simplified algorithm. The calculation mode is combined with the phased array antenna, the pointing angle of the phased array antenna can be calculated in real time only by receiving satellite orbit information in real time and injecting relay satellite orbit information, and the method is simple in design and high in compatibility.

In addition, the radio frequency transceiver module realizes the identification of the SSA link and the SMA link, and can ensure that the receiver can self-identify the link mode and switch the working mode of the return link according to the capturing condition of the current forward link receiving signal in the SSA link and the SMA link, and autonomously realize the transmission of the return link, specifically, the principle is as follows:

(1) generating 2 channels and 4 paths of local orthogonal carriers with different frequency points aiming at an SSA mode and an SMA mode; (2) externally input AD sampling signals are respectively mixed with 2-channel local carriers; (3) the pseudo-code generator generates a replica pseudo-random code under the drive of a code clock; (4)4 paths of mixing signals are respectively related to the copied pseudo random codes for despreading; (5) respectively accumulating, combining and caching the data subjected to the 2-channel orthogonal correlation processing; (6) performing fast FFT (fast Fourier transform) on the 2-channel data in a time-sharing manner to obtain a square sum after transformation; (7) judging whether the 2-path square sum maximum value exceeds a preset threshold or not, and acquiring a signal; (8) determining a current working link mode and generating a link working mode; (9) and switching the working frequency point of the return link according to the mode.

The link working mode can be adaptively changed without externally sending a mode switching instruction to auxiliary information after the link is identified or a ground, and the working mode of the return link is switched. The abnormal phenomenon of mode switching caused by the abnormal conditions of instruction receiving error, ground instruction sending failure, auxiliary information error and the like is avoided, and the self-adaptive capacity of the receiver is improved. The identification method meets the integrated diversified design concept of the current equipment, and has the advantages of simple design, high reliability, short development period and the like.

The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention in other forms, and any person skilled in the art may apply the above modifications or changes to the equivalent embodiments with equivalent changes, without departing from the technical spirit of the present invention, and any simple modification, equivalent change and change made to the above embodiments according to the technical spirit of the present invention still belong to the protection scope of the technical spirit of the present invention.