Arrow-mounted relay terminal and control method thereof

Abstract

The application relates to the field of arrow-carrying space-based measurement and control technology, and particularly discloses an arrow-carrying relay terminal and a control method thereof. The method comprises the following steps: determining the positions of a plurality of relay satellites in a geocentric inertial coordinate system at the next moment; converting the positions of the relay satellites in the geocentric inertial coordinate system into positions in an arrow-carrying relay terminal antenna measurement coordinate system; converting the positions of the relay satellites in the arrow-carrying relay terminal antenna measurement coordinate system into positions of the relay satellites in an arrow-carrying relay terminal antenna polar coordinate system; determining the link radiation efficiency of a phased array antenna in the direction of each relay satellite according to the position of each relay satellite in the arrow-carrying relay terminal antenna polar coordinate system; comparing the link radiation efficiency in each direction, and determining the relay satellite corresponding to the maximum value in each link radiation efficiency as a target relay satellite; and establishing a communication connection between the target relay satellite and the phased array antenna. The relay satellite in communication with the launch vehicle can be determined during the flight of the launch vehicle.

Description

Technical Field

[0001] This application relates to the field of rocket-borne space-based telemetry and control technology, and in particular to a rocket-borne relay terminal and its control method. Background Technology

[0002] Currently, with the increasing maturity of relay satellite technology, space-based telemetry and control is being used more and more widely in the launch control of carrier rockets. The carrier rocket communicates with the relay satellite via a relay terminal installed on it, transmitting telemetry data to the relay satellite and then to the ground command and control center, thus providing launch control support for the carrier rocket.

[0003] When relying on relay satellites to provide telemetry and control support for launch vehicles, the relay terminal installed on the launch vehicle needs to control the phased array antenna beam to point towards the relay satellite after liftoff to achieve uninterrupted communication with the relay satellite. However, if multiple medium-Earth orbit (MEO) relay satellites are used for space-based telemetry and control support for launch vehicles, considering the high probability of launch delays and the uncertainty of the delay time, and because MEO relay satellites are in continuous motion relative to the ground, it is impossible to pre-set which MEO relay satellite the rocket-borne relay terminal will communicate with during launch, either before launch or before installation. Summary of the Invention

[0004] Therefore, it is necessary to provide an onboard relay terminal and its control method to address the above problems.

[0005] According to a first aspect of the embodiments of this application, a control method for a rocket-borne relay terminal is provided, the rocket-borne relay terminal including a phased array antenna; the control method for the rocket-borne relay terminal includes:

[0006] Determine the positions of several relay satellites in the geocentric inertial coordinate system at the next moment;

[0007] The positions of each relay satellite in the geocentric inertial coordinate system are converted into the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna.

[0008] The positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna are converted into the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna.

[0009] Based on the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, determine the link radiation efficiency of the phased array antenna in the direction of each relay satellite.

[0010] Compare the link radiation efficiency in each direction, and determine the relay satellite corresponding to the maximum value of each link radiation efficiency as the target relay satellite;

[0011] Establish a communication connection between the target relay satellite and the phased array antenna.

[0012] In one embodiment, the step of converting the positions of each relay satellite in the geocentric inertial coordinate system to the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna includes:

[0013] The positions of each relay satellite in the geocentric inertial coordinate system are converted into their positions in the geocentric fixed coordinate system.

[0014] The positions of each relay satellite in the geocentric fixed coordinate system are converted to their positions in the launch coordinate system.

[0015] The positions of each relay satellite in the launch coordinate system are converted to their positions in the launch vehicle body coordinate system.

[0016] The positions of each relay satellite in the launch vehicle's coordinate system are converted into the positions of each relay satellite in the onboard relay terminal antenna measurement coordinate system.

[0017] In one embodiment, in the step of converting the positions of each relay satellite in the geocentric inertial coordinate system to their positions in the geocentric fixed coordinate system, the position transformation is performed using the following formula:

[0018]

[0019] in,( ) represents the position of the relay satellite in the geocentric fixed coordinate system, ( This indicates the position of the relay satellite in the geocentric inertial coordinate system. This represents the rotation angle between the geocentric fixed coordinate system and the geocentric inertial coordinate system.

[0020] In one embodiment, in the step of converting the positions of each relay satellite in the geocentric fixed coordinate system to the positions of each relay satellite in the launch coordinate system, the position transformation is performed using the following formula:

[0021]

[0022] in,( ) indicates the position of the relay satellite in the launch coordinate system, ( This indicates the position of the relay satellite in the geocentric fixed coordinate system. Indicates the launch azimuth angle. Represents the origin of the launch coordinate system The latitude of the earth, Represents the origin of the launch coordinate system Earth's longitude, Represents the origin of the launch coordinate system Leveling elevation Indicates the Earth's oblateness. Represents the origin of the launch coordinate system The radius of curvature of the circle containing the y-axis. , It represents the radius of the Earth's equator.

[0023] In one embodiment, in the step of converting the positions of each relay satellite in the launch coordinate system to the positions of each relay satellite in the launch vehicle body coordinate system, the position transformation is performed using the following formula:

[0024]

[0025] in,( ) indicates the position of the relay satellite in the launch vehicle's coordinate system. ) indicates the position of the relay satellite in the launch coordinate system, ( ) indicates the position of the launch vehicle in the launch coordinate system, ( () represents the flight attitude angles of the launch vehicle, namely roll angle, yaw angle, and pitch angle.

[0026] In one embodiment, in the step of converting the positions of each relay satellite in the launch vehicle body coordinate system to the positions of each relay satellite in the onboard relay terminal antenna measurement coordinate system, the position transformation is performed using the following formula:

[0027]

[0028] in,( ) indicates the position of the relay satellite in the coordinate system of the rocket-borne relay terminal antenna measurement. This indicates the position of the relay satellite in the launch vehicle's coordinate system. This indicates the installation angle of the phased array antenna in the transverse direction of the launch vehicle. This indicates the tilt angle of the phased array antenna along the longitudinal direction of the launch vehicle. This indicates the longitudinal installation height of the phased array antenna on the launch vehicle. This indicates the installation distance of the phased array antenna in the radial direction of the launch vehicle.

[0029] In one embodiment, in the step of converting the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna to the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, the position transformation is performed using the following formula:

[0030]

[0031] in,( This indicates the position of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This represents the origin of the polar coordinate system from the relay satellite to the rocket-borne relay terminal antenna, which is also the center of the phased array antenna. distance, This indicates the azimuth angle, which is the center of the phased array antenna. The projection of the vector to the relay satellite onto the antenna array and The angle between the axes, This indicates the elevation angle, i.e., the center of the phased array antenna. The angle between the vector to the relay satellite and the antenna array, ( () indicates the position of the relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna.

[0032] In one embodiment, the step of determining the link radiation efficiency of the phased array antenna in the direction of each relay satellite based on the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna includes:

[0033] For each relay satellite, the link radiation efficiency of the phased array antenna in that direction is determined based on the elevation angle of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna and the distance from the relay satellite to the center of the phased array antenna.

[0034] In one embodiment, in the step of determining the link radiation efficiency of the phased array antenna in that direction based on the elevation angle of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna and the distance from the relay satellite to the center of the phased array antenna, the link radiation efficiency in that direction is determined by the following formula:

[0035]

[0036] in, This indicates the link radiation efficiency of the phased array antenna of the rocket-borne relay terminal in the direction of a certain relay satellite. This represents the elevation angle of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the distance from the relay satellite to the center of the phased array antenna.

[0037] In one embodiment, in the step of comparing the link radiation efficiency in each direction and determining the relay satellite corresponding to the maximum value among the link radiation efficiencies as the target relay satellite, the target relay satellite is determined using the following formula:

[0038]

[0039] Among them, the target relay satellite is the first of several relay satellites. One relay satellite, This represents the elevation angle of the target relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the link radiation efficiency of the phased array antenna of the rocket-borne relay terminal in the direction of the target relay satellite. This represents the distance from the target relay satellite to the center of the phased array antenna in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the preset lower limit value of the pitch angle.

[0040] In one embodiment, the step of establishing a communication connection between the target relay satellite and the phased array antenna includes:

[0041] The azimuth and elevation angles of the target relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna are used as the beam pointing angle of the phased array antenna at the next moment and sent to the corresponding beam control unit of the phased array antenna so that the beam control unit controls the phased array antenna beam to point towards the target relay satellite.

[0042] According to a second aspect of the embodiments of this application, a rocket-borne relay terminal is provided, including a phased array antenna, a digital baseband unit, and a control unit. The digital baseband unit and the control unit are both electrically connected to the phased array antenna, and the control unit is configured to execute the control method of the rocket-borne relay terminal described above.

[0043] The rocket-borne relay terminal and its control method provided in this application first determine the positions of several relay satellites in the geocentric inertial coordinate system at the next moment. Then, the positions of each relay satellite in the geocentric inertial coordinate system are converted into the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna. Next, the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna are converted into the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. Then, based on the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, the link radiation efficiency of the phased array antenna of the rocket-borne relay terminal in the direction of each relay satellite can be determined. The link radiation efficiency in the direction of each relay satellite is compared, and the relay satellite corresponding to the maximum value of each link radiation efficiency is determined as the target relay satellite. Finally, a communication connection between the target relay satellite and the phased array antenna is established. The above method can effectively solve the problem that, due to the high probability of launch delays and the uncertainty of the delay time, as well as the continuous movement of relay satellites, especially medium-Earth orbit relay satellites, relative to the ground, it is impossible to pre-set which relay satellite the rocket-borne terminal should communicate with during launch or installation. This allows the rocket-borne relay terminal to determine which relay satellite to choose for communication based on the link radiation efficiency of the relay terminal in the direction of each relay satellite during the rocket's flight. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of a rocket-borne relay terminal provided in one embodiment of this application;

[0045] Figure 2 and Figure 3 A schematic diagram of the installation of the phased array antenna in the rocket-borne relay terminal provided in an embodiment of this application on a launch vehicle;

[0046] Figure 4 A flowchart illustrating a control method for a rocket-borne relay terminal provided in an embodiment of this application;

[0047] Figure 5 This is a flowchart of step S300 in the control method of an onboard relay terminal provided in an embodiment of this application.

[0048] Explanation of reference numerals in the attached figures:

[0049] 100. Launch vehicle;

[0050] 200. Rocket-borne relay terminal; 210. Phased array antenna; 211. Transmitting assembly; 212. Beam control unit; 220. Processor; 221. Digital baseband unit; 222. Control unit. Detailed Implementation

[0051] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0052] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0055] Currently, with the increasing maturity of relay satellite technology, space-based telemetry, tracking, and command (TT&C) is being used more and more widely in launch vehicle launch TT&C. Launch vehicles communicate with relay satellites via relay terminals installed on them, transmitting telemetry data to the relay satellites and then to the ground command and control center, thus providing launch TT&C support. The relay terminal installed on the launch vehicle typically consists of two parts: a phased array antenna, mounted on the surface of the launch vehicle, used to radiate electromagnetic waves for communication with the relay satellite; and a processor, installed in the instrument compartment inside the launch vehicle, connected to the phased array antenna via cables, used for data modulation and radio frequency conversion signal processing.

[0056] When relying on relay satellites to provide telemetry and control support for launch vehicles, the relay terminal installed on the launch vehicle (hereinafter referred to as the rocket-borne relay terminal) needs to control the phased array antenna beam to point towards the relay satellite after liftoff to achieve uninterrupted communication with the relay satellite. If relying on geostationary orbit relay satellites to provide space-based telemetry and control support, since the geostationary orbit relay satellites are stationary relative to the ground (i.e., their position coordinates in the launch coordinate system are fixed), the rocket-borne relay terminal can determine which geostationary orbit relay satellite to communicate with before flight or even before installation. Even if the launch is delayed, it will not be affected because the position of the geostationary orbit relay satellite relative to a point on the rocket's flight trajectory does not change during normal flight. Currently, some existing patents regarding the calculation of the pointing angle of rocket-borne relay terminals are specifically designed for geostationary orbit relay satellites.

[0057] While geostationary relay satellites offer the advantage of being relatively stationary relative to the ground, providing stable long-term coverage of the Asia-Pacific region, the limited number of available geostationary orbit slots, their strategic importance, and their already heavily occupied status make it extremely difficult for commercial spacecraft to secure geostationary orbit slots. Therefore, medium Earth orbit (MEO) relay satellite technology has gained increasing attention in recent years. Compared to geostationary relay satellites, MEO relay satellites have a much larger number of slots available, making application easier. Although MEO relay satellites are constantly in motion relative to the ground, and a single relay satellite can only cover the Asia-Pacific region for a short period (e.g., a few hours), long-term coverage of the region can be achieved by deploying multiple MEO relay satellites in a single orbital plane using a relay method.

[0058] If multiple medium-Earth orbit (MEO) relay satellites are used for space-based telemetry, tracking, and command (TT&C) support for launch vehicles, considering the high probability of launch delays and the uncertainty of the delay time, and because MEO relay satellites are constantly moving relative to the ground, it is impossible to pre-set which MEO relay satellite the onboard relay terminal will communicate with during flight. Communication must be performed in real-time during rocket flight based on certain criteria. This application aims to solve the problem of selecting multiple satellites when relying on MEO relay satellite systems for space-based TT&C of launch vehicles. This selection criterion is a significant innovation of this application compared to existing related patents.

[0059] To address the aforementioned issues, this application provides an arrow-borne relay terminal and its control method.

[0060] In one embodiment, a control method for a rocket-borne relay terminal is provided. This control method allows for the determination and comparison of the link radiation efficiency of the rocket-borne relay terminal in the directions of multiple relay satellites during rocket flight, thereby determining which relay satellite the rocket-borne relay terminal should select for communication.

[0061] Among them, reference Figure 1 The rocket-borne relay terminal 200 includes a phased array antenna 210 and a processor 220 connected by a cable. The phased array antenna 210 specifically includes an antenna array, a transmitting component 211, and a beam control unit 212. The processor 220 specifically includes a digital baseband unit 221 and a control unit 222. When the processor 220 receives rocket telemetry data, time, position, attitude, and other information transmitted from the launch vehicle 100 control system, it can modulate the rocket telemetry data through the digital baseband unit 221 and transmit it through the cable to the transmitting component 211, which then radiates it outwards. The control unit 222 in the processor 220 can select one relay satellite from multiple relay satellites, and then control the antenna beam to point towards the selected relay satellite through the beam control unit 212 in the phased array antenna 210. The specific satellite selection method is the control method of the rocket-borne relay terminal 200 provided in this application.

[0062] Specifically, refer to Figure 4 The control method for the rocket-borne relay terminal 200 provided in this embodiment includes the following steps:

[0063] Step S200: Determine the positions of several relay satellites in the geocentric inertial coordinate system at the next moment.

[0064] Assume there are several relay satellites, generally referring to medium Earth orbit relay satellites. These relay satellites take turns passing over the Asia-Pacific region. At certain times, the launching vehicle 100 in flight can communicate with two or more relay satellites simultaneously; however, due to power limitations, it can generally only select one relay satellite for communication.

[0065] Before the launch vehicle 100 takes off, ground operators can transmit the latest orbital elements of several relay satellites to the processor 220 of the onboard relay terminal 200. Before the launch vehicle 100 takes off, the control unit 222 can determine the coordinates of each relay satellite in the geocentric inertial coordinate system at the next moment based on the pre-stored latest orbital elements of each relay satellite.

[0066] In the geocentric inertial coordinate system, the origin of the coordinate system is parallel to the Earth's center. coincide, O e X i The axis points to the vernal equinox (the intersection of the equatorial plane and the ecliptic plane). O e Z i The axis is parallel to the Earth's instantaneous axis of rotation. O e Y i The axes are determined by the right-hand rule. The geocentric inertial coordinate system does not rotate with the Earth; the commonly used geocentric inertial coordinate system is generally J2000.0.

[0067] Step S300: Convert the position of each relay satellite in the geocentric inertial coordinate system to the position of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal 200 antenna.

[0068] Once the positions of each relay satellite in the geocentric inertial coordinate system at the next moment are determined, a series of rotational transformations can be used to convert from the geocentric inertial coordinate system to the measurement coordinate system of the rocket-borne relay terminal 200 antenna, thereby determining the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal 200 antenna at the next moment.

[0069] Step S400: Convert the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal 200 antenna into the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna.

[0070] Once the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal 200 antenna at the next moment are determined, they can be converted into the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, which facilitates the subsequent calculation of the link radiation efficiency corresponding to each relay satellite.

[0071] Step S500: Determine the link radiation efficiency of the phased array antenna 210 in the direction of each relay satellite based on the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna.

[0072] Link radiation efficiency refers to the power radiation efficiency of the rocket-borne relay terminal 200 in the microwave signal link transmitted to the relay satellite. In this embodiment, the microwave link radiation efficiency of the rocket-borne relay terminal 200 in the direction of each relay satellite can be estimated based on the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna for subsequent comparison.

[0073] Step S600: Compare the link radiation efficiency in each direction, and determine the relay satellite corresponding to the maximum value of each link radiation efficiency as the target relay satellite.

[0074] After determining the link radiation efficiency in the direction of each relay satellite, the link radiation efficiency in the direction of each relay satellite can be compared, and then the maximum value of the link radiation efficiency can be determined. The relay satellite corresponding to the maximum value is then determined as the target relay satellite, that is, the relay satellite that communicates with the rocket-borne relay terminal 200.

[0075] Step S700: Establish a communication connection between the target relay satellite and the phased array antenna 210.

[0076] After the target relay satellite is identified, a communication connection can be established between the target relay satellite and the phased array antenna 210. Specifically, the azimuth and elevation angles of the target relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna can be used as the beam pointing angle of the phased array antenna 210 at the next moment and sent to the beam control unit 212 corresponding to the phased array antenna 210, so that the beam control unit 212 controls the beam of the phased array antenna 210 to point towards the target relay satellite, thereby establishing a communication connection between the target relay satellite and the phased array antenna 210.

[0077] The control method for the rocket-borne relay terminal 200 provided in this application embodiment first determines the positions of several relay satellites in the geocentric inertial coordinate system at the next moment. Then, the positions of each relay satellite in the geocentric inertial coordinate system are converted into the positions of each relay satellite in the antenna measurement coordinate system of the rocket-borne relay terminal 200. Next, the positions of each relay satellite in the antenna measurement coordinate system of the rocket-borne relay terminal 200 are converted into the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. Then, based on the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, the link radiation efficiency in the direction of each relay satellite is determined. The link radiation efficiency in the direction of each relay satellite is compared, and the relay satellite corresponding to the maximum value of each link radiation efficiency is determined as the target relay satellite. Finally, a communication connection is established between the target relay satellite and the phased array antenna 210. The above method can effectively solve the problem that, due to the high probability of launch delay and the uncertainty of the delay time of the launch vehicle 100, and the continuous movement of relay satellites, especially medium-orbit relay satellites, relative to the ground, it is impossible to pre-set which relay satellite the rocket-borne terminal should establish communication with during launch or installation. This allows the rocket-borne relay terminal 200 to determine which relay satellite to choose for communication based on the link radiation efficiency in the microwave signal link transmitted by the rocket-borne relay terminal 200 during the flight of the launch vehicle 100.

[0078] Reference Figure 5 In one embodiment, step S300, which is the step of converting the positions of each relay satellite in the geocentric inertial coordinate system to the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal 200 antenna, may include:

[0079] Step S310: Convert the positions of each relay satellite in the geocentric inertial coordinate system to the positions of each relay satellite in the geocentric fixed coordinate system.

[0080] Specifically, in one embodiment, the position transformation can be performed using the following formula:

[0081]

[0082] in,( ) represents the position of the relay satellite in the geocentric fixed coordinate system, ( This indicates the position of the relay satellite in the geocentric inertial coordinate system. This represents the rotation angle between the geocentric fixed coordinate system and the geocentric inertial coordinate system.

[0083] The geocentric fixed coordinate system is defined as follows: the origin of the coordinate system is perpendicular to the geocenter. O e coincide, Oe X e The axis points in the direction of the intersection of the equatorial plane and the Greenwich Meridian. O e Z e The axis coincides with the Earth's axis and points towards the North Pole. O e Y e The axes are determined by the right-hand rule. The geocentric fixed coordinate system rotates with the Earth. There is a rotation angle between the geocentric fixed coordinate system and the geocentric inertial coordinate system. Ω The rotation angle can be calculated from the Earth's rotational angular velocity and the time interval between the next moment and 12:00 on January 1, 2000.

[0084] Step S320: Convert the positions of each relay satellite in the geocentric fixed coordinate system to the positions of each relay satellite in the launch coordinate system.

[0085] Specifically, in one embodiment, the position transformation can be performed using the following formula:

[0086]

[0087] in,( ) indicates the position of the relay satellite in the launch coordinate system, ( This indicates the position of the relay satellite in the geocentric fixed coordinate system. Indicates the launch azimuth angle. Represents the origin of the launch coordinate system The latitude of the earth, Represents the origin of the launch coordinate system Earth's longitude, Represents the origin of the launch coordinate system Leveling elevation Indicates the Earth's oblateness. Represents the origin of the launch coordinate system The radius of curvature of the circle containing the y-axis. , It represents the radius of the Earth's equator.

[0088] The launch coordinate system is defined as follows: Origin of the coordinate system O l The center of mass of the rocket is located when the launch vehicle 100 is erected at the launch pad. X l O l Z l The plane passes through the origin of the coordinate system. O lThe tangent plane that is tangent to the Earth's reference ellipsoid. O l X l The axis lies within the tangential plane and points in the direction of launch, typically determined by the launch azimuth angle. A 0 is defined as the angle between the launch direction and local true north, with clockwise measurement being positive. O l Y l The axis is the normal vector of the tangent plane passing through the origin of the launch station, with upward being positive. O l Z l Determined by the right-hand rule.

[0089] Step S330: Convert the position of each relay satellite in the launch coordinate system to the position of each relay satellite in the launch vehicle 100 body coordinate system.

[0090] Specifically, in one embodiment, the position transformation can be performed using the following formula:

[0091]

[0092] in,( ) indicates the position of the relay satellite in the coordinate system of the launch vehicle 100. ) indicates the position of the relay satellite in the launch coordinate system, ( ) indicates the position of launch vehicle 100 in the launch coordinate system, ( The angles () represent the flight attitude angles of the launch vehicle 100, namely the roll angle, yaw angle, and pitch angle.

[0093] The coordinate system of the Long March 100 carrier rocket is defined as follows: the origin of the coordinate system is located at the rocket's center of mass. O b , O b X b The axis is the longitudinal axis of symmetry of the arrow body, pointing towards the tip of the head. O b Y b The axis points to the third plane in the longitudinal plane of the rocket body (parallel to the negative direction of the launch direction before takeoff). O b Z b The axis is determined by the right-hand rule.

[0094] Step S340: Convert the positions of each relay satellite in the launch vehicle 100 body coordinate system to the positions of each relay satellite in the antenna measurement coordinate system of the onboard relay terminal 200.

[0095] Specifically, in one embodiment, the position transformation can be performed using the following formula:

[0096]

[0097] in,( ) indicates the position of the relay satellite in the coordinate system of the 200 antenna measurement terminal on the rocket. This indicates the position of the relay satellite in the coordinate system of the Long March 100 carrier rocket. This indicates the installation angle of the phased array antenna 210 in the transverse direction of the launch vehicle 100. This indicates the tilt angle of the phased array antenna 210 in the longitudinal direction of the launch vehicle 100. This indicates the longitudinal installation height of the phased array antenna 210 on the launch vehicle 100. This indicates the installation distance of the phased array antenna 210 in the radial direction of the launch vehicle 100.

[0098] The coordinate system for the 200-antenna measurement of the rocket-borne relay terminal is defined as follows: (Refer to...) Figure 2 The origin of the coordinate system is located at the center of the 210 phased array antenna. O a , O a X a The axis points towards the rocket's nose, relative to the rocket's body coordinate system. O b X b The axis lies in a plane. O a Z a The vertical antenna array points outward from the rocket body. O a Y a The axis lies within the antenna array and is determined by the right-hand rule.

[0099] For details, please refer to Figure 2 Due to the significant difference in size, the dimensions of the rocket-borne relay terminal 200 and the rocket are not drawn to scale in the figure for ease of explanation. The black rectangle in the center of the front view is the phased array antenna 210 of the rocket-borne relay terminal 200, and the gray part is the outer surface of the launch vehicle 100. O b The origin of the coordinate system of the Long March 100 carrier rocket body is... O b X b Y b Zb For the coordinate system of the launch vehicle 100, Figure 3 middle Y b ’O b ’ Z b ’ for Y b O b Z b plane along O b X b Vertical axis translation H a The plane after O a The origin of the coordinate system for the 200 antenna measurement of the rocket-borne relay terminal is generally coincided with the geometric center of the antenna array. O a X a Y a Z a The coordinate system for measuring the rocket-borne relay terminal 200 antenna is given. The distance between the installation position of the phased array antenna 210 in the rocket-borne relay terminal 200 and the longitudinal axis of the rocket is given. H a The installation angle on the cross-section of the launch vehicle is 100. α The angle, the tilt angle of the antenna array is β .

[0100] In one embodiment, in step S400, which is the step of converting the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal 200 antenna into the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, the position conversion is performed using the following formula:

[0101]

[0102] in,( This indicates the position of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. The origin of the polar coordinate system from the relay satellite to the rocket-borne relay terminal antenna is represented by the center of the phased array antenna 210. distance, This indicates the azimuth angle, i.e., the center of the phased array antenna 210. The projection of the vector to the relay satellite onto the antenna array and The angle between the axes, This indicates the elevation angle, which is the center of the phased array antenna 210. The angle between the vector to the relay satellite and the antenna array, ( () indicates the position of the relay satellite in the coordinate system of the rocket-borne relay terminal 200 antenna measurement.

[0103] The polar coordinate system of the rocket-borne relay terminal antenna is defined as follows: the origin of the coordinate system is located at the center of the 210 phased array antenna. O a ,distance R Indicates the distance of the target from the origin, azimuth angle A The projection of the vector from the origin to the target onto the antenna array surface and O a X a The angle between the axes is determined by O a X a Axis to O a Y a The axis rotation direction is positive, and the pitch angle is positive. E The angle between the vector from the origin to the target and the antenna array surface is represented by the vector from the array surface to the target. O a Z a Directional rotation is positive.

[0104] In one embodiment, step S500, which is the step of determining the link radiation efficiency of the phased array antenna 210 in the direction of each relay satellite based on the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, includes:

[0105] For each relay satellite, the link radiation efficiency in the direction of the relay satellite is determined based on the elevation angle of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna and the distance from the relay satellite to the center of the phased array antenna 210.

[0106] That is, in this embodiment, the elevation angle of the relay satellite in the coordinate system of the rocket-borne relay terminal antenna and the distance from the relay satellite to the center of the phased array antenna 210 can be determined. Then, based on these two, the signal radiation efficiency in the microwave signal link from the rocket-borne relay terminal 200 to the direction of the relay satellite can be calculated, which is referred to as the link radiation efficiency in the direction of the relay satellite.

[0107] Specifically, in one embodiment, the link radiation efficiency of the relay satellite can be determined using the following formula:

[0108]

[0109] in, This indicates the link radiation efficiency of the phased array antenna 210 of the rocket-borne relay terminal in the direction of a certain relay satellite. This represents the elevation angle of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the distance from the relay satellite to the center of the phased array antenna 210.

[0110] In one embodiment, in step S600, namely the step of comparing the link radiation efficiency in each direction and determining the relay satellite corresponding to the maximum value among the link radiation efficiencies as the target relay satellite, the target relay satellite is determined using the following formula:

[0111]

[0112] Among them, the target relay satellite is the first of several relay satellites. One relay satellite, This represents the elevation angle of the target relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the link radiation efficiency of the phased array antenna of the rocket-borne relay terminal in the direction of the target relay satellite. This represents the distance from the target relay satellite to the center of the phased array antenna 210 in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the preset lower limit value of the pitch angle.

[0113] In other words, the "maximum link radiation efficiency" criterion means that the link radiation efficiency is maximized when the pitch angle is greater than a preset lower limit. Among these, The minimum elevation angle limit is preset based on the maximum off-axis scanning angle designed for the phased array antenna 210. E min =90°-SA max , SA max This indicates the maximum scanning angle of the phased array antenna 210. Generally, the scanning range of the phased array antenna 210 is ±60°. E min Set as 30° .

[0114] Once the relay satellite corresponding to the maximum value in the link radiation efficiency is determined, the azimuth and elevation angles of that relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna can be used as the beam pointing angle of the phased array antenna 210 at the next moment. This beam pointing angle is sent to the beam control unit 212 of the phased array antenna 210 to control the beam of the phased array antenna 210 to point to the selected relay satellite, thereby realizing communication between the two, that is, realizing communication between the rocket-borne relay terminal 200 and a selected relay satellite during rocket flight.

[0115] Based on the same inventive concept, and referring to Figure 1 In another embodiment, a rocket-borne relay terminal 200 is also provided, including a phased array antenna 210, a digital baseband unit 221, and a control unit 222. Both the digital baseband unit 221 and the control unit 222 are electrically connected to the phased array antenna 210, and both belong to a processor 220. The control unit 222 is configured to execute the control method of the rocket-borne relay terminal 200 described above.

[0116] Specifically, the phased array antenna 210 may include an antenna array, a transmitting component 211, and a beam control unit 212. The digital baseband unit 221 may be electrically connected to the transmitting component 211 in the phased array antenna 210, and the control unit 222 may be electrically connected to the beam control unit 212 in the phased array antenna 210.

[0117] For details regarding the phased array antenna 210, digital baseband unit 221, and control unit 222, please refer to the specific description in the control method of the rocket-borne relay terminal 200 provided in the aforementioned embodiments, which will not be repeated here.

[0118] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A control method for a rocket-borne relay terminal, characterized in that, The rocket-borne relay terminal is used to select relay satellites in medium Earth orbit for communication in real time during rocket flight. The onboard relay terminal includes a phased array antenna. The control method for the onboard relay terminal includes: Determine the positions of several relay satellites in the geocentric inertial coordinate system at the next moment; The positions of each relay satellite in the geocentric inertial coordinate system are converted into the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna. The positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna are converted into the positions of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. Based on the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna, determine the link radiation efficiency of the phased array antenna in the direction of each relay satellite; including: for each relay satellite, using the following formula, based on the elevation angle of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna and the distance from the relay satellite to the center of the phased array antenna, determine the link radiation efficiency of the phased array antenna in that direction: ,in, This indicates the link radiation efficiency of the phased array antenna of the rocket-borne relay terminal in the direction of a certain relay satellite. This represents the elevation angle of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the distance from the relay satellite to the center of the phased array antenna. Compare the link radiation efficiency in each direction, and determine the relay satellite corresponding to the maximum value of each link radiation efficiency as the target relay satellite; Establish a communication connection between the target relay satellite and the phased array antenna.

2. The control method for the rocket-borne relay terminal according to claim 1, characterized in that, The step of converting the positions of each relay satellite in the geocentric inertial coordinate system into the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna includes: The positions of each relay satellite in the geocentric inertial coordinate system are converted into their positions in the geocentric fixed coordinate system. The positions of each relay satellite in the geocentric fixed coordinate system are converted to their positions in the launch coordinate system. The positions of each relay satellite in the launch coordinate system are converted to their positions in the launch vehicle body coordinate system. The positions of each relay satellite in the launch vehicle's coordinate system are converted into the positions of each relay satellite in the onboard relay terminal antenna measurement coordinate system.

3. The control method for the rocket-borne relay terminal according to claim 2, characterized in that, In the step of converting the positions of each relay satellite in the geocentric inertial coordinate system to their positions in the geocentric fixed coordinate system, the following formula is used for position transformation: in,( ) represents the position of the relay satellite in the geocentric fixed coordinate system, ( This indicates the position of the relay satellite in the geocentric inertial coordinate system. This represents the rotation angle between the geocentric fixed coordinate system and the geocentric inertial coordinate system.

4. The control method for the rocket-borne relay terminal according to claim 2, characterized in that, In the step of converting the positions of each relay satellite in the geocentric fixed coordinate system to their positions in the launch coordinate system, the following formula is used for position transformation: in,( ) indicates the position of the relay satellite in the launch coordinate system, ( This indicates the position of the relay satellite in the geocentric fixed coordinate system. Indicates the launch azimuth angle. Represents the origin of the launch coordinate system The latitude of the earth, Represents the origin of the launch coordinate system Earth's longitude, Represents the origin of the launch coordinate system Leveling elevation Indicates the Earth's oblateness. Represents the origin of the launch coordinate system The radius of curvature of the circle containing the y-axis. , It represents the radius of the Earth's equator.

5. The control method for the rocket-borne relay terminal according to claim 2, characterized in that, In the step of converting the positions of each relay satellite in the launch coordinate system to their positions in the launch vehicle body coordinate system, the following formula is used for position transformation: in,( ) indicates the position of the relay satellite in the launch vehicle's coordinate system. ) indicates the position of the relay satellite in the launch coordinate system, ( ) indicates the position of the launch vehicle in the launch coordinate system, ( () represents the flight attitude angles of the launch vehicle, namely roll angle, yaw angle, and pitch angle.

6. The control method for the rocket-borne relay terminal according to claim 2, characterized in that, In the step of converting the positions of each relay satellite in the launch vehicle's coordinate system to the positions of each relay satellite in the onboard relay terminal antenna measurement coordinate system, the following formula is used for position transformation: in,( ) indicates the position of the relay satellite in the coordinate system of the rocket-borne relay terminal antenna measurement. This indicates the position of the relay satellite in the launch vehicle's coordinate system. This indicates the installation angle of the phased array antenna in the transverse direction of the launch vehicle. This indicates the tilt angle of the phased array antenna along the longitudinal direction of the launch vehicle. This indicates the longitudinal installation height of the phased array antenna on the launch vehicle. This indicates the installation distance of the phased array antenna in the radial direction of the launch vehicle.

7. The control method for the rocket-borne relay terminal according to claim 1, characterized in that, In the step of converting the positions of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna into the polar coordinate system of the rocket-borne relay terminal antenna, the position transformation is performed using the following formula: in,( This indicates the position of the relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This represents the origin of the polar coordinate system from the relay satellite to the rocket-borne relay terminal antenna, which is also the center of the phased array antenna. distance, This indicates the azimuth angle, which is the center of the phased array antenna. The projection of the vector to the relay satellite onto the antenna array and The angle between the axes, This indicates the elevation angle, i.e., the center of the phased array antenna. The angle between the vector to the relay satellite and the antenna array, ( () indicates the position of the relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna.

8. The control method for the rocket-borne relay terminal according to claim 1, characterized in that, In the step of comparing the link radiation efficiency in each direction and determining the relay satellite corresponding to the maximum value among the link radiation efficiencies as the target relay satellite, the target relay satellite is determined using the following formula: Among them, the target relay satellite is the first of several relay satellites. One relay satellite, This represents the elevation angle of the target relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the link radiation efficiency of the phased array antenna of the rocket-borne relay terminal in the direction of the target relay satellite. This represents the distance from the target relay satellite to the center of the phased array antenna in the polar coordinate system of the rocket-borne relay terminal antenna. This indicates the preset lower limit value of the pitch angle.

9. The control method for the rocket-borne relay terminal according to claim 1, characterized in that, The steps for establishing a communication connection between the target relay satellite and the phased array antenna include: The azimuth and elevation angles of the target relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna are used as the beam pointing angle of the phased array antenna at the next moment and sent to the corresponding beam control unit of the phased array antenna so that the beam control unit controls the phased array antenna beam to point towards the target relay satellite.

10. A rocket-borne relay terminal, characterized in that, The device includes a phased array antenna, a digital baseband unit, and a control unit. The digital baseband unit and the control unit are both electrically connected to the phased array antenna. The control unit is configured to execute the control method of the rocket-borne relay terminal according to any one of claims 1-9.

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