An ultra-low orbit microsatellite lightweight TT&C system and its implementation method

Abstract

The present invention discloses an ultra-low orbit microsatellite lightweight TT&C system and its implementation method. The system includes a TT&C relay integrated machine, which includes a baseband processing module for implementing ground ranging TT&C tasks and relay TT&C tasks; a TT&C transponder for implementing ground ranging TT&C tasks; a microwave network for signal synthesis filtering and signal distribution; a TT&C antenna for signal reception and transmission; a relay power amplifier for power amplifying the signals output by the TT&C relay integrated machine. The TT&C relay integrated machine and the TT&C transponder are heterogeneous backups for each other. The present invention meets the design constraints of overall lightweight and miniaturization of the system. Moreover, for an ultra-low orbit satellite in flight, the aerodynamic environment it experiences has extremely high requirements for the operating temperature of the antenna exposed outside the cabin. The present invention avoids direct aerodynamic heating and meets the use requirements in the ultra-low orbit thermal environment. At the same time, the present invention meets the stable connection of the communication link in various satellite attitudes by designing a unique antenna installation method.

Description

Technical Field

[0001] The present invention relates to the design of a TT&C system for ultra-low orbit microsatellites, belonging to the field of space vehicle system design. More specifically, it relates to a lightweight TT&C system for ultra-low orbit microsatellites and its implementation method. Background Art

[0002] The satellite TT&C system is an important means to establish communication between the ground and the satellite, enabling people on the ground to timely measure the satellite's operating orbit, understand the working conditions of the satellite platform and its payload, and various engineering parameters, and control the satellite's flight orbit attitude and the working state of subsystems. The TT&C system can complete ground TT&C tasks and also relay TT&C tasks. When the satellite enters the country, a ground-to-satellite spread-spectrum TT&C system is adopted to ensure the reliability and security of TT&C, and cooperate with the ground TT&C station to complete telemetry, telecontrol, and tracking ranging and orbit measurement tasks. When the satellite operates outside the country and is in the visible arc of the relay satellite, a relay spread-spectrum TT&C system is adopted to complete the satellite's telemetry and telecontrol tasks through the relay satellite relaying via the ground central station.

[0003] The satellite TT&C antenna is an important part of the satellite TT&C system. Its function is to complete the transmission and interaction of TT&C information between the satellite and the ground by converting the radio energy with various information through the conversion between space waves and guided waves. With the development of space technology, space vehicles are developing towards microsatellites that are simpler, lighter, and smaller. Therefore, in addition to some common requirements of general antennas, such as bandwidth, radiation pattern, gain, polarization, and voltage standing wave ratio, the ultra-low orbit microsatellite TT&C antenna also has some emphasized technical requirements, such as weight limit and extreme geometric dimensions, as well as environmental adaptability. On the one hand, for microsatellites, weight and available space limitations are inevitably important considerations in the design of the vehicle system; on the other hand, during the satellite's on-orbit operation, the antenna is exposed outside the cabin and will inevitably be subjected to external space environments such as high and low temperature alternation, radiation and other thermal environment factors, as well as mechanical environment factors such as vibration, shock, and noise during the launch process. For ultra-low orbits below 120 km, the force and thermal effects on the antenna will be more significant. Therefore, the selection, material selection, and installation method of the antenna are all important links in the design of the TT&C system.

[0004] Therefore, it is necessary to provide a lightweight TT&C system for ultra-low orbit microsatellites and its implementation method to meet the design constraints of overall system lightweight and miniaturization, and to meet the use in the ultra-low orbit thermal environment. At the same time, in order for the satellite to meet the long-term operation in the ultra-low orbit, various attitude modes will be adopted to improve the surface-to-mass ratio. Therefore, it is necessary to design a unique antenna installation method to ensure the stable connection of the communication link in various satellite attitudes. Summary of the Invention

[0005] The object of the present invention is to provide a lightweight TT&C system for ultra-low orbit microsatellites and its implementation method.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] An ultra-low orbit microsatellite lightweight TT&C system, comprising:

[0008] A TT&C relay integrated machine, including a baseband processing module for implementing ground ranging TT&C tasks and relay TT&C tasks;

[0009] A TT&C transponder for implementing ground ranging TT&C tasks;

[0010] A microwave network for signal synthesis filtering and signal distribution;

[0011] A TT&C antenna for signal reception and transmission;

[0012] A relay power amplifier for amplifying the power of the signal output by the TT&C relay integrated machine;

[0013] The TT&C relay integrated machine and the TT&C transponder are heterogeneous backups of each other.

[0014] Preferably, the TT&C antenna includes a space-ground TT&C antenna and a relay TT&C antenna. The space-ground TT&C antenna includes a space-ground TT&C antenna facing the sky and a space-ground TT&C antenna facing the ground, and works in a form of sharing the same antenna for both receiving and transmitting; the relay TT&C antenna includes a relay receiving antenna facing the sky and a relay transmitting antenna facing the sky, and works in a form of separating the receiving and transmitting antennas.

[0015] Preferably, the TT&C antenna is a dual-frequency microstrip antenna. The upper patch of the space-ground TT&C antenna sharing the same antenna for both receiving and transmitting covers the TT&C transmitting frequency band, and the lower patch covers the TT&C receiving frequency band.

[0016] Preferably, the TT&C antenna includes an antenna radome, a printed circuit board, and an antenna bottom plate, and is installed on an installation bracket. The installation bracket is installed on the side of the satellite body in a way that is inclined about the ±Z axis direction of the satellite body.

[0017] Among them, the +Z axis direction is the satellite's direction towards the ground, and the -Z axis direction is the satellite's direction towards the sky.

[0018] Preferably, the space-ground TT&C antenna facing the sky is installed near the side facing the sky on the first side of the satellite body in the +Y axis direction, and the space-ground TT&C antenna facing the ground is installed near the side facing the ground on the second side of the satellite body in the -Y axis direction corresponding to the first side. The installation angles of the space-ground TT&C antennas are complementary;

[0019] Both the relay receiving antenna facing the sky and the relay transmitting antenna facing the sky are installed near the side facing the sky on the first side or the second side of the satellite body in the ±Y axis direction. The installation angles of the two relay antennas are the same;

[0020] Among them, the +Y-axis direction is the negative normal direction of the satellite orbital plane, and the -Y-axis direction is the normal direction of the satellite orbital plane.

[0021] Preferably, the inclined installation method includes determining the installation angle that maximizes the antenna array gain, and calculating the installation angle using the following formula:

[0022] G(θ,φ) = ηD(θ,φ)

[0023] D(θ,φ) = 4π(|E θ (θ,φ)| 2 +|E φ (θ,φ)| 2 ) / P

[0024]

[0025] G(θ,φ) = 10lgD(θ,φ) + 10lgη

[0026] Among them,

[0027] (θ,φ) is the installation angle;

[0028] θ is the angle between the tracking and control antenna and the XOZ plane;

[0029] φ is the angle between the tracking and control antenna and the YOZ plane;

[0030] η is the radiation efficiency, which is a positive real number ≤ 1;

[0031] D(θ,φ) is the antenna directivity coefficient;

[0032] G(θ,φ) is the antenna array gain;

[0033] P is the radiation power;

[0034] When the satellite is flying steadily towards the ground, the flight direction is the +X axis, the negative normal direction of the orbital plane is the +Y axis, the direction of the satellite towards the ground is the +Z axis, and the centroid position of the satellite is O.

[0035] Preferably, in the direction of the windward side during flight, the height of the installation bracket is higher than the height of the tracking and control antenna, the cross-sectional width of the installation bracket is greater than the surface width of the tracking and control antenna, the surface of the installation bracket is coated with a heat insulation component, and the tracking and control antenna is installed in a heat-insulated manner with the installation bracket.

[0036] Preferably, the material of the radome is polyimide, and the materials of the antenna bottom plate and the installation bracket are aluminum alloy.

[0037] A method for realizing a lightweight tracking and control system for ultra-low orbit microsatellites, the steps include:

[0038] The sky-earth measurement and control antenna and the earth-sky measurement and control antenna receive the uplink signal. The microwave network synthesizes and filters the uplink signal and outputs it to the measurement and control relay integrated machine and the measurement and control transponder respectively.

[0039] The measurement and control relay integrated machine and the measurement and control transponder respectively complete the reception and demodulation of the uplink remote control signal and the measurement signal, and generate the downlink telemetry radio frequency signal and the measurement radio frequency signal and output them to the microwave network.

[0040] The microwave network synthesizes and filters the downlink signal and sends it through the measurement and control antenna to form an uplink and downlink bidirectional radio frequency link, and completes the functions of remote control, telemetry and ranging with the ground measurement and control station.

[0041] Preferably, the method further includes:

[0042] The relay receiving antenna receives the forward radio frequency signal from the relay satellite and sends it into the measurement and control relay integrated machine to complete the capture and tracking of the forward remote control signal.

[0043] The measurement and control relay integrated machine generates a return telemetry radio frequency signal and outputs it to the relay power amplifier.

[0044] The relay power amplifier amplifies the power of the return telemetry radio frequency signal and transmits it to the relay satellite through the on-sky relay transmitting antenna to complete the remote control and telemetry functions of the relay measurement and control task.

[0045] The beneficial effects of the present invention are as follows:

[0046] The present invention can meet the design requirements of small satellites for simplification, light weight and miniaturization of on-board equipment. By adopting an intensive design concept, the architecture of the measurement and control system is minimized, and unnecessary waste of the whole satellite resources caused by objective factors such as weight and size is avoided.

[0047] The present invention can meet the operation requirements of ultra-low orbit satellites. When selecting the antenna and layout design, an installation bracket is considered to be added. On the one hand, it ensures the inclined installation of the antenna and plays a role in fixing and supporting; on the other hand, based on the fact that the upper surface height of the installation bracket is higher than the antenna height and the surface width of the antenna is smaller than the cross-section of the bracket, the high-temperature air flow on the windward surface is effectively avoided from directly heating the antenna surface, and the influence brought by the aerodynamic heat environment heating is well solved.

[0048] The present invention can realize the normal link communication function under various attitudes of the aircraft, support the attitude maneuver of the aircraft, and ensure that when the aircraft is flying vertically or lying on its side, the measurement and control antenna can realize communication with the sky and the ground, avoiding the situation of communication interruption caused by the attitude adjustment of the aircraft. Description of the Drawings

[0049] The following further details the specific implementation manners of the present invention in conjunction with the drawings.

[0050] Figure 1 Show the block diagram of the lightweight TT&C system for the ultra-low orbit microsatellite of the present invention.

[0051] Figure 2 Show the schematic diagram of the installation of the space-ground TT&C antenna on the whole satellite of the present invention.

[0052] Figure 3(a) shows the simulation result of the two-dimensional pattern of the receiving frequency points of the TT&C antenna array in an embodiment of the present invention.

[0053] Figure 3(b) shows the simulation result of the two-dimensional pattern of the transmitting frequency points of the TT&C antenna array in an embodiment of the present invention. Detailed implementation manners

[0054] To describe the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments and the accompanying drawings. Similar components in the drawings are denoted by the same reference numerals. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention. In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. Unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0055] It should also be noted that in the description of the present invention, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0056] Such as Figure 1As shown in FIG. -3, an embodiment of the present invention provides an ultra-low orbit microsatellite lightweight TT&C system, including:

[0057] A TT&C relay integrated machine, including a baseband processing module for implementing ground ranging TT&C tasks and relay TT&C tasks;

[0058] A TT&C transponder for implementing ground ranging TT&C tasks;

[0059] A microwave network for signal synthesis filtering and signal distribution;

[0060] A TT&C antenna for signal reception and transmission;

[0061] A relay power amplifier for power amplifying the signal output by the TT&C relay integrated machine;

[0062] The TT&C relay integrated machine and the TT&C transponder are heterogeneous backups of each other.

[0063] The ultra-low orbit microsatellite TT&C system in this embodiment meets the usage requirements in the ultra-low orbit thermal environment, meets the usage requirements in various attitudes of the aircraft, and meets the design constraints of the overall lightweight and miniaturization of the system.

[0064] Specifically, the TT&C system of the present invention includes a TT&C relay integrated machine, a TT&C transponder, a relay power amplifier, a microwave network, a TT&C antenna and a cable. The TT&C relay integrated machine realizes the core processing of the TT&C system. Its baseband processing module can simultaneously complete tasks such as ground ranging TT&C and relay TT&C. Its core indicators include receiving sensitivity and transmitting power, etc. The TT&C transponder serves as a backup for TT&C tasks and completes ground ranging and TT&C tasks. Its core indicators include receiving sensitivity and transmitting power, etc. The relay power amplifier mainly completes the amplification of the relay reverse signal. Its core indicator includes output power. The microwave network mainly completes signal transceiver combining and distribution. The TT&C antenna completes signal reception and transmission.

[0065] The present invention adopts an intensive design concept, realizes the minimization of the TT&C system architecture, and avoids unnecessary waste of the whole satellite resources due to objective factors such as weight and size.

[0066] In an optional embodiment, the TT&C antenna includes a space-ground TT&C antenna and a relay TT&C antenna. The space-ground TT&C antenna includes a space-ground TT&C antenna facing the sky and a space-ground TT&C antenna facing the ground, and works in a form of sharing the same antenna for receiving and transmitting;

[0067] The relay TT&C antenna includes a relay receiving antenna facing the sky and a relay transmitting antenna facing the sky, and works in a form of separating the receiving and transmitting antennas.

[0068] In an optional embodiment, the measurement and control antenna is a dual-frequency microstrip antenna. The upper patch of the space-ground measurement and control antenna for transceiver sharing covers the measurement and control transmission frequency band, and the lower patch covers the measurement and control reception frequency band. In an optional embodiment, the measurement and control relay integrated machine adopts a working form of baseband composite processing, which can not only implement the ground ranging measurement and control task, but also implement the relay measurement and control task.

[0069] Specifically, the measurement and control antenna completes signal reception and transmission. Among them, the space-ground measurement and control antenna adopts a transceiver-sharing method, and 2 sets are configured in the system; the relay measurement and control antenna adopts a transceiver-separated method, and 1 set for reception and 1 set for transmission are configured in the system. The present invention conducts an effective integrated design for the internal part of the measurement and control system, and uses ways such as antenna composite use and baseband composite processing to meet the design constraints of overall light weight and miniaturization of the system.

[0070] The present invention selects the antenna and layout design considering the installation of mounting brackets, which ensures the inclined installation of the antenna and plays a role of fixed support.

[0071] In an optional embodiment, the space-ground measurement and control antenna facing the sky is installed near the sky-facing side on the first side in the +Y-axis direction of the satellite body, and the space-ground measurement and control antenna facing the ground is installed near the ground-facing side on the second side in the -Y-axis direction corresponding to the first side, and the installation angles of the space-ground measurement and control antennas are complementary;

[0072] The relay receiving antenna facing the sky and the relay transmitting antenna facing the sky are both installed near the sky-facing side on the first side or the second side in the ±Y-axis direction of the satellite body, and the installation angles of the two relay measurement and control antennas are the same;

[0073] Among them, the +Y-axis direction is the negative normal direction of the satellite orbit plane, and the -Y-axis direction is the normal direction of the satellite orbit plane.

[0074] In an optional embodiment, the inclined installation method includes determining the installation angle that maximizes the antenna array gain, and calculating the installation angle using the following formula,

[0075] G(θ,φ) = ηD(θ,φ)

[0076] D(θ,φ) = 4π(|E θ (θ,φ)| 2 +|E φ (θ,φ)| 2 ) / P

[0077]

[0078] G(θ,φ) = 10lgD(θ,φ) + 10lgη

[0079] Among them,

[0080] (θ, φ) is the installation angle;

[0081] θ is the angle between the tracking and control antenna and the XOZ plane;

[0082] φ is the angle between the tracking and control antenna and the YOZ plane;

[0083] η is the radiation efficiency, which is a positive real number ≤1;

[0084] D(θ,φ) is the antenna directivity coefficient;

[0085] G(θ,φ) is the antenna array gain;

[0086] P is the radiated power;

[0087] The flight direction of the satellite during steady-state flight over the earth is the +X axis, the negative normal direction of the orbital plane is the +Y axis, the direction of the satellite over the earth is the +Z axis, and the center of mass position of the satellite is O.

[0088] The present invention selects an antenna and considers installing a mounting bracket in layout design, which effectively avoids the high-temperature airflow on the windward side directly heating the antenna surface, and well solves the influence of aerodynamic thermal environment heating.

[0089] In an optional embodiment, the measurement and control antenna includes a radome, a printed circuit board and an antenna base plate, which are installed on a mounting bracket, and the mounting bracket is installed on the side of the star body in a tilted installation manner with respect to the ±Z axis direction of the star body.

[0090] In an optional embodiment, the material of the antenna cover is polyimide, and the material of the antenna base plate and the mounting bracket is aluminum alloy.

[0091] In an optional embodiment, in the windward direction of flight, the surface height of the measurement and control antenna mounting bracket is higher than the height of the measurement and control antenna, the cross-sectional width of the mounting bracket is larger than the surface width of the measurement and control antenna, the surface of the mounting bracket is covered with a thermal insulation component, and the measurement and control antenna is installed in a thermally insulated manner from the mounting bracket.

[0092] Specifically, the flight direction of the satellite during steady-state flight over the earth is the +X axis, the negative normal of the orbital plane is the +Y axis, the direction over the earth is the +Z axis, the center of mass position of the satellite is O, and the designed antenna installation requirements meet the following requirements:

[0093] The antenna is installed on the side of the satellite, and the satellite-to-ground tracking and control antennas are arranged on two corresponding surfaces on the side, and the installation angles of the two antennas are complementary; the relay tracking and control antenna is installed on one of the side surfaces, and the installation angles of the two antennas are consistent; there is no obstruction within the 60° field of view of a single antenna.

[0094] The antenna is installed at an angle, with an angle of θ with the XOZ plane and an angle of φ with the YOZ plane. The antenna gain G(θ,φ) can be expressed as:

[0095] G(θ, φ) = ηD(θ, φ)

[0096] D(θ, φ) = 4π(|E θ (θ, φ)| 2 +|E φ (θ, φ)| 2 ) / P

[0097]

[0098] where η is the radiation efficiency and is a positive real number ≤ 1, D(θ, φ) is the antenna directivity coefficient, P is the radiation power, and when the gain is expressed in dB, there is:

[0099] G(θ, φ) = 10lgD(θ, φ) + 10lgη (dB)

[0100] When the gain of the antenna array is maximized, the appropriate values of (θ, φ) are determined. At this time, the gain index should include cable loss, polarization loss, etc.; analyze the influence of antenna gain and select the optimal one to ensure the stable connection of the communication link under various satellite attitudes.

[0101] The present invention supports the attitude maneuver of the aircraft, ensuring that the TT&C antenna can achieve communication with the sky and the ground when the aircraft is flying vertically or horizontally, avoiding the situation of communication interruption caused by the attitude adjustment of the aircraft.

[0102] Specifically, the TT&C antenna is installed in an inclined manner. On the one hand, it can ensure the stable connection of the communication link under various satellite attitudes; on the other hand, by installing the antenna support, it avoids the direct heating of the antenna by the aerodynamic heat in the ultra-low orbit.

[0103] The aerodynamic environment experienced by the ultra-low orbit satellite flight has extremely high requirements for the working temperature of the antenna exposed outside the cabin. The present invention adopts an antenna with a small volume and high temperature resistance, and effectively avoids direct aerodynamic heating by designing the installation support. In the direction of the windward side during flight, the surface height of the antenna installation support is required to be higher than the height of the antenna body, and the cross-sectional width of the support is greater than the surface width of the antenna; the surface of the support is coated with a heat insulation component; the antenna is installed with heat insulation from the support.

[0104] Moreover, in order for the satellite to meet the long-term operation in the ultra-low orbit, it will adopt various attitude methods to improve the surface-to-mass ratio. The present invention designs a unique antenna installation method, analyzes the influence of antenna gain and selects the optimal one to ensure the stable connection of the communication link under various satellite attitudes.

[0105] Another embodiment of the present invention provides a method for implementing the ultra-low orbit microsatellite lightweight TT&C system, and the steps include:

[0106] The space-earth measurement and control antenna and the earth-space measurement and control antenna receive the uplink signal. The microwave network synthesizes and filters the uplink signal and outputs it to the measurement and control relay integrated machine and the measurement and control transponder respectively;

[0107] The measurement and control relay integrated machine and the measurement and control transponder respectively complete the reception and demodulation of the uplink telecommand signal and the measurement signal, and generate the downlink telemetry radio frequency signal and the measurement radio frequency signal and output them to the microwave network;

[0108] The microwave network synthesizes and filters the downlink signal and then outputs two radio frequency signals, which are sent through the measurement and control antenna to form an uplink and downlink bidirectional radio frequency link, and complete the functions of telecommand, telemetry and ranging with the ground measurement and control station.

[0109] Specifically, in the space-earth measurement and control mission, the measurement and control relay integrated machine and the measurement and control transponder are heterogeneous backups for each other. One space-earth measurement and control antenna is installed for each of the space and the ground to receive the uplink signal. After being synthesized and filtered by the microwave network, the signal is sent into the measurement and control relay integrated machine and the measurement and control transponder respectively. The two respectively complete the reception and demodulation of the uplink telecommand signal and the measurement signal, and then generate the downlink telemetry radio frequency signal and the measurement radio frequency signal. After being synthesized and filtered by the microwave network, two radio frequency signals are output and sent through the measurement and control antenna, so as to form an uplink and downlink bidirectional radio frequency link and complete the functions of telecommand, telemetry and ranging with the ground measurement and control station.

[0110] In an optional embodiment, the method further includes:

[0111] The relay receiving antenna receives the forward radio frequency signal from the relay satellite and sends it into the measurement and control relay integrated machine to complete the acquisition and tracking of the forward telecommand signal;

[0112] The measurement and control relay integrated machine generates a return telemetry radio frequency signal and outputs it to the relay power amplifier;

[0113] The relay power amplifier amplifies the power of the return telemetry radio frequency signal and transmits it to the relay satellite through the space relay transmitting antenna, completing the functions of telecommand and telemetry in the relay measurement and control mission.

[0114] Specifically, in the relay measurement and control mission, the relay receiving antenna receives the forward radio frequency signal from the relay satellite and sends it into the measurement and control relay integrated machine to complete the acquisition and tracking of the forward telecommand signal; at the same time, a return telemetry radio frequency signal is generated, and after being power-amplified by the relay power amplifier, it is transmitted to the relay satellite through the relay transmitting antenna, so as to complete the functions of telecommand and telemetry in the relay measurement and control. The measurement and control relay integrated machine adopts the working form of baseband composite processing, which can not only realize the ranging measurement and control mission for the ground, but also realize the relay measurement and control mission.

[0115] In a specific implementation of the present invention, a lightweight TT&C system for ultra-low orbit microsatellites is designed with a total weight not greater than 5.53 kg, an antenna gain greater than -1 dBi within the range of ±60°, and greater than -5 dBi within the range of ±80°. The antenna array gain is not less than -7.5 dBi within the ±60° spherical beam coverage range and not less than -13.5 dBi within the ±80° spherical beam coverage range, including microwave network loss, high-frequency cable loss, polarization loss, etc.

[0116] The TT&C antenna selects a dual-frequency microstrip antenna, which has the characteristics of simple structure, low profile, and light weight. The upper patch of the transceiver shared antenna covers the TT&C transmission frequency band, and the lower patch covers the TT&C reception frequency band, with narrowband characteristics and a frequency bandwidth of up to 20 MHz. The TT&C antenna is installed on the side of the satellite body, where the satellite-ground TT&C antennas are respectively arranged on two corresponding sides of the side, and the installation angles of the two antennas are complementary; the relay TT&C antenna is installed on one side of the side, and the installation angles of the two antennas are the same; ensure that there is no obstruction within the 60° field of view of a single antenna; the antenna is installed obliquely, with an angle of θ = 25° with the XOZ plane and an angle of φ = 90° with the YOZ plane;

[0117] Determine θ = 25° and φ = 90°. The satellite-ground TT&C antenna facing the sky is installed in the +Y axis direction of the satellite body near the side facing the sky, forming an angle of 25° with the XOZ plane, that is, an angle of 25° with the +Z axis, and an angle of 90° with the YOZ plane; the satellite-ground TT&C antenna facing the ground is installed in the -Y axis direction of the satellite body near the side facing the ground, forming an angle of 25° with the XOZ plane, that is, an angle of 25° with the -Z axis, and an angle of 90° with the YOZ plane. The relay receiving antenna and the relay transmitting antenna are both installed in the -Y axis direction of the satellite body near the side facing the sky, forming an angle of 25° with the XOZ plane, that is, an angle of 25° with the +Z axis, and an angle of 90° with the YOZ plane.

[0118] As shown in the simulation results in Figure 3, after design, the gain of the antenna in this embodiment is greater than 1 dBi within the range of ±60°, greater than -1.5 dBi within the range of ±75°, and greater than -3.5 dBi within the range of ±80°. According to engineering experience, the difference between the measured gain and the simulated gain of the antenna due to factors such as processing errors can generally be controlled within about 1 - 2 dB, and the antenna design indicators better meet the usage requirements.

[0119] Based on the operating requirements of the ultra-low orbit, through the analysis and calculation of the aerodynamic heat effect, it can be known that the aerodynamic heat flux in the frontal windward area is 5100 W / m 2 , the radiative equilibrium temperature is 297 °C, and the aerodynamic heat flux in the oblique side windward area is 560 W / m 2 , and the radiative equilibrium temperature is 69 °C.

[0120] The measurement and control antenna mainly consists of a radome, a printed circuit board, and an antenna base plate, and is installed on the satellite bracket. The radome material is selected as polyimide, and the antenna base plate and bracket materials are selected as aluminum alloy. After the thermal analysis and simulation of the antenna, it can be seen from the temperature contour maps of each structural component that the highest temperature on the windward side of the outer surface of the radome is 297 °C, the highest temperature near the solder joints of the antenna printed circuit board is about 120 °C, and the highest temperature of the bracket is 67.2 °C. The radome uses polyimide material, and the general temperature tolerance can reach 400 - 500 °C, so the radome can work normally. The temperature tolerance near the solder joints of the antenna printed circuit board is generally not lower than 180 °C, and the antenna printed circuit board can work normally. Therefore, the antenna as a whole can withstand the influence of aerodynamic heating environment.

[0121] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or variations derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. An ultra-low orbit microsatellite lightweight TT&C system, characterized in that, Including: A measurement and control relay integrated machine, including a baseband processing module for implementing ground ranging measurement and control tasks and relay measurement and control tasks; A measurement and control transponder for implementing ground ranging measurement and control tasks; A microwave network for signal synthesis filtering and signal distribution; A measurement and control antenna for signal reception and transmission; A relay power amplifier for power amplifying the signal output by the measurement and control relay integrated machine; The measurement and control relay integrated machine and the measurement and control transponder are heterogeneous backups for each other; The measurement and control antenna includes a space-ground measurement and control antenna and a relay measurement and control antenna. The space-ground measurement and control antenna includes a space-ground measurement and control antenna facing the sky and a space-ground measurement and control antenna facing the ground, and works in a transceiver-sharing form; The relay measurement and control antenna includes a relay receiving antenna facing the sky and a relay transmitting antenna facing the sky, and works in a transceiver-separated form; The measurement and control antenna includes an antenna radome, a printed circuit board, and an antenna base plate, and is installed on an installation bracket. The installation bracket is installed on the side of the satellite body in a way that is inclined about the ±Z axis direction of the satellite body; Among them, the +Z axis direction is the satellite's direction towards the ground, and the -Z axis direction is the satellite's direction towards the sky; The space-ground measurement and control antenna facing the sky is installed near the sky-facing side on the first side of the satellite body in the +Y axis direction, and the space-ground measurement and control antenna facing the ground is installed near the ground-facing side on the second side of the satellite body in the -Y axis direction corresponding to the first side. The installation angles of the space-ground measurement and control antennas are complementary; Both the relay receiving antenna facing the sky and the relay transmitting antenna facing the sky are installed near the sky-facing side on the first side or the second side of the satellite body in the ±Y axis direction. The installation angles of the two relay antennas are the same; Among them, the +Y axis direction is the negative normal direction of the satellite orbit plane, and the -Y axis direction is the normal direction of the satellite orbit plane.

2. The ultra-low orbit microsatellite lightweight TT&C system according to claim 1, wherein The measurement and control antenna is a dual-frequency microstrip antenna. The upper patch of the transceiver-sharing space-ground measurement and control antenna covers the measurement and control transmission frequency band, and the lower patch covers the measurement and control reception frequency band.

3. The ultra-low orbit microsatellite lightweight TT&C system according to claim 1, characterized in that, The inclined installation method includes determining the installation angle that maximizes the antenna array gain, and calculating the installation angle using the following formula: G(θ,φ) = ηD(θ,φ) D(θ, φ) = 4π(|E θ (θ, φ)| 2 +|E φ (θ, φ)| 2 ) / P G(θ,φ) = 10lgD(θ,φ) + 10lgη Among them, (θ,φ) is the installation angle; θ is the angle between the measurement and control antenna and the XOZ plane; φ is the angle between the measurement and control antenna and the YOZ plane; η is the radiation efficiency, which is a positive real number ≤ 1; D(θ,φ) is the antenna directivity coefficient; G(θ,φ) is the antenna array gain; P is the radiation power; When the satellite is in a steady state flying towards the ground, the flying direction is the +X axis, the negative normal direction of the orbit plane is the +Y axis, the satellite's direction towards the ground is the +Z axis, and the centroid position of the satellite is O.

4. The ultra-low orbit microsatellite lightweight TT&C system according to claim 1, wherein In the direction of the windward side during flight, the height of the installation bracket is higher than the height of the measurement and control antenna. The cross-sectional width of the installation bracket is greater than the surface width of the measurement and control antenna. The surface of the installation bracket is covered with a heat insulation component, and the measurement and control antenna is installed with heat insulation from the installation bracket.

5. The ultra-low orbit microsatellite lightweight TT&C system according to claim 1, characterized in that The material of the antenna radome is polyimide, and the materials of the antenna base plate and the installation bracket are aluminum alloy.

6. A method for implementing the system according to any one of claims 1-5, characterized in that the steps Including: The space-ground measurement and control antenna facing the sky and the space-ground measurement and control antenna facing the ground receive the uplink signal. The microwave network synthesizes and filters the uplink signal and outputs it to the measurement and control relay integrated machine and the measurement and control transponder respectively; The measurement and control relay integrated machine and the measurement and control transponder respectively receive and demodulate the uplink telecommand signal and the measurement signal, generate the downlink telemetry RF signal and the measurement RF signal, and output them to the microwave network; The microwave network synthesizes and filters the downlink signal, transmits it through the measurement and control antenna, forms an uplink and downlink bidirectional RF link, and completes the functions of telecommand, telemetry, and ranging with the ground measurement and control station; The relay receiving antenna receives the forward RF signal from the relay satellite and sends it into the measurement and control relay integrated machine to complete the acquisition and tracking of the forward telecommand signal; The measurement and control relay integrated machine generates a reverse telemetry RF signal and outputs it to the relay power amplifier; The relay power amplifier amplifies the power of the reverse telemetry RF signal, transmits it through the on-sky relay transmitting antenna to the relay satellite, and completes the telecommand and telemetry functions of the relay measurement and control task.

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