Rocket-borne relay terminal and control method thereof

Abstract

The invention relates to the technical field of rocket-borne space-based measurement and control, and particularly discloses a rocket-borne 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 of the relay satellites in a rocket-borne relay terminal antenna measurement coordinate system; converting the position of each relay satellite in the measurement coordinate system of the rocket-borne relay terminal antenna into the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna; determining the link radiation efficiency of the phased-array antenna in the direction of each relay satellite according to the position of each relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna; comparing the link radiation efficiency in each direction and determining the relay satellite corresponding to the maximum value in the link radiation efficiency as a target relay satellite; and establishing communication connection between the target relay satellite and the phased-array antenna. The relay satellites communicating with the carrier rocket can be determined in the flight process of the carrier rocket.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of missile-borne space-based TT&C technology, in particular to a missile-borne relay terminal and a control method thereof. BACKGROUND

[0002] Currently, with the increasing maturity of relay satellite technology, space-based TT&C is increasingly widely applied in launch vehicle launch TT&C. The launch vehicle communicates with the relay satellite through the relay terminal installed thereon, transmits telemetry data to the relay satellite and then to the ground command control center, thereby realizing launch vehicle launch TT&C support.

[0003] When relying on a relay satellite to provide launch vehicle launch TT&C support, the relay terminal installed on the launch vehicle needs to control the phased array antenna beam to point to the relay satellite after the rocket takes off, so as to realize uninterrupted communication with the relay satellite. However, if multiple medium-orbit relay satellites are relied on to carry out launch vehicle launch space-based TT&C support, considering that the launch vehicle launch postponement probability is not low and the postponement time is uncertain, since the medium-orbit relay satellites are in continuous motion relative to the ground, it is impossible to set in advance which medium-orbit relay satellite the missile-borne relay terminal communicates with during the launch process before the launch or installation. SUMMARY

[0004] Therefore, it is necessary to provide a missile-borne relay terminal and a control method thereof in view of the above problems.

[0005] According to a first aspect of the embodiments of the present application, a control method of a missile-borne relay terminal is provided, the missile-borne relay terminal comprising a phased array antenna; the control method of the missile-borne relay terminal comprising: determining the positions of a plurality of relay satellites in an earth-centered inertial coordinate system at a next time; converting the positions of the plurality of relay satellites in the earth-centered inertial coordinate system into positions of the plurality of relay satellites in an antenna measurement coordinate system of the missile-borne relay terminal respectively; converting the positions of the plurality of relay satellites in the antenna measurement coordinate system of the missile-borne relay terminal into positions of the plurality of relay satellites in a polar coordinate system of the antenna of the missile-borne relay terminal respectively; determining the link radiation efficiency of the phased array antenna in the direction of each of the plurality of relay satellites according to the positions of the plurality of relay satellites in the polar coordinate system of the antenna of the missile-borne relay terminal; comparing the link radiation efficiency in each direction, and determining the relay satellite corresponding to the maximum value of the link radiation efficiency as a target relay satellite; establishing a communication connection between the target relay satellite and the phased array antenna.

[0006] In one of the embodiments, the step of converting the position of each relay satellite in the geocentric inertial coordinate system into the position of each relay satellite in the launch vehicle body coordinate system comprises: converting the position of each relay satellite in the geocentric inertial coordinate system into the position of each relay satellite in the geocentric fixed coordinate system; converting the position of each relay satellite in the geocentric fixed coordinate system into the position of each relay satellite in the launch coordinate system; converting the position of each relay satellite in the launch coordinate system into the position of each relay satellite in the launch vehicle body coordinate system; converting the position of each relay satellite in the launch vehicle body coordinate system into the position of each relay satellite in the launch vehicle terminal antenna coordinate system.

[0007] In one of the embodiments, in the step of converting the position of each relay satellite in the geocentric inertial coordinate system into the position of each relay satellite in the geocentric fixed coordinate system, the position conversion is performed by using the following formula: wherein, represents the position of the relay satellite in the geocentric fixed coordinate system, represents the position of the relay satellite in the geocentric inertial coordinate system, represents the rotation angle between the geocentric fixed coordinate system and the geocentric inertial coordinate system.

[0008] In one of the embodiments, in the step of converting the position of each relay satellite in the geocentric fixed coordinate system into the position of each relay satellite in the launch coordinate system, the position conversion is performed by using the following formula: wherein, represents the position of the relay satellite in the launch coordinate system, represents the position of the relay satellite in the geocentric fixed coordinate system, represents the launch azimuth angle, represents the geodetic latitude of the origin of the launch coordinate system, represents the geodetic longitude of the origin of the launch coordinate system, represents the normal height of the origin of the launch coordinate system, represents the flattening of the Earth, represents the radius of the prime vertical circle passing through the origin of the launch coordinate system, , represents the radius of the equator of the Earth. represents the radius of the equator of the Earth.​​​

[0009] 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: 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.

[0010] 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: 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.

[0011] 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: 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 array plane, represents the position of the relay satellite in the coordinate system of the antenna measurement of the on-board relay terminal.

[0012] In one of the embodiments, the step of determining the link radiation efficiency of the phased array antenna in the direction of each relay satellite according to the position of the relay satellite in the polar coordinate system of the antenna measurement of the on-board relay terminal comprises: For each relay satellite, the link radiation efficiency of the phased array antenna in the direction is determined according to the elevation angle of the relay satellite in the polar coordinate system of the antenna measurement of the on-board relay terminal and the distance from the relay satellite to the center of the array plane of the phased array antenna.

[0013] In one of the embodiments, in the step of determining the link radiation efficiency of the phased array antenna in the direction according to the elevation angle of the relay satellite in the polar coordinate system of the antenna measurement of the on-board relay terminal and the distance from the relay satellite to the center of the array plane of the phased array antenna, the link radiation efficiency in the direction is determined by the following formula: wherein, represents the link radiation efficiency of the phased array antenna of the on-board relay terminal in the direction of the certain relay satellite, represents the elevation angle of the relay satellite in the polar coordinate system of the antenna measurement of the on-board relay terminal, represents the distance from the relay satellite to the center of the array plane of the phased array antenna.

[0014] In one of the embodiments, in the step of comparing the link radiation efficiencies in the directions and determining the relay satellite corresponding to the maximum value of the link radiation efficiencies as the target relay satellite, the target relay satellite is determined by the following formula: wherein, the target relay satellite is the i-th relay satellite in the plurality of relay satellites, represents the elevation angle of the target relay satellite in the polar coordinate system of the antenna measurement of the on-board relay terminal, represents the link radiation efficiency of the phased array antenna of the on-board relay terminal in the direction of the target relay satellite, represents the distance from the target relay satellite to the center of the array plane of the phased array antenna in the polar coordinate system of the antenna measurement of the on-board relay terminal, represents the preset lower limit value of the elevation angle. In one of the embodiments, the step of establishing the communication connection between the target relay satellite and the phased array antenna comprises:

[0015] ​The azimuth angle and the elevation angle of the target relay satellite in the polar coordinate system of the rocket-borne relay terminal antenna are sent to a wave control unit corresponding to the phased array antenna as the beam pointing angle of the phased array antenna at the next time, so that the wave control unit controls the phased array antenna to point to the target relay satellite.

[0016] According to a second aspect of the embodiments of the present application, a rocket-borne relay terminal is provided, which comprises a phased array antenna, a digital baseband unit and a control unit, the digital baseband unit and the control unit are electrically connected to the phased array antenna, and the control unit is configured to perform the control method of the rocket-borne relay terminal.

[0017] The rocket-borne relay terminal and the control method thereof provided by the embodiments of the present application can first determine the positions of a plurality of relay satellites in the geocentric inertial coordinate system at the next time, then convert the positions of the relay satellites in the geocentric inertial coordinate system into the positions of the relay satellites in the rocket-borne relay terminal antenna measurement coordinate system respectively, and then convert the positions of the relay satellites in the rocket-borne relay terminal antenna measurement coordinate system into the positions of the relay satellites in the rocket-borne relay terminal antenna polar coordinate system respectively. Then, the link radiation efficiency of the rocket-borne relay terminal phased array antenna in the direction of each relay satellite can be determined according to the positions of the relay satellites in the rocket-borne relay terminal antenna polar coordinate system. The relay satellite corresponding to the maximum link radiation efficiency is determined as the target relay satellite by comparing the link radiation efficiencies in the direction of each relay satellite. Finally, the communication connection between the target relay satellite and the phased array antenna is established. Through the above method, the problem that it is impossible to determine which relay satellite should be selected for communication by the rocket-borne relay terminal during the launch of the carrier rocket before the launch or installation of the rocket-borne terminal is solved, because the launch delay probability of the carrier rocket is not low and the delay time is uncertain, and the relay satellites, especially the medium-orbit relay satellites, continuously move relative to the ground. Therefore, the rocket-borne relay terminal can determine which relay satellite should be selected for communication according to the link radiation efficiency of the rocket-borne relay terminal in the direction of each relay satellite during the flight of the carrier rocket. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The structural schematic diagram of the rocket-borne relay terminal provided by an embodiment of the present application is shown in the figure; Figure 2 And Figure 3 The installation schematic diagram of the phased array antenna in the rocket-borne relay terminal provided by an embodiment of the present application on the carrier rocket is shown in the figure; Figure 4 The flowchart of the control method of the rocket-borne relay terminal provided by an embodiment of the present application is shown in the figure; Figure 5 The flowchart of step S300 in the control method of the rocket-borne relay terminal provided by an embodiment of the present application is shown in the figure.

[0019] Reference Signs List: 100, launch vehicle; 200, on-board relay terminal; 210, phased array antenna; 211, transmit assembly; 212, wave control unit; 220, processor; 221, digital baseband unit; 222, control unit. DETAILED DESCRIPTION

[0020] For the purpose of the present application, the application will be described in relation to the enclosed drawings. It is to be understood that the application can assume various forms of implementation and that the application is not limited to the embodiments described hereinafter. On the contrary, the embodiments are provided as examples of the disclosure, which can be understood more thoroughly and completely by virtue of the disclosure.

[0021] In the present application, unless otherwise clearly specified and limited, the terms "mounting", "connection", "linking", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements or interaction relationship between two elements, unless otherwise clearly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0022] The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise clearly specified and limited.

[0023] 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 in the description of the present application is only for the purpose of describing specific embodiments and is not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0024] At present, with the increasing maturity of the relay satellite technology, space-based TT&C is increasingly widely used in launch vehicle TT&C. The launch vehicle communicates with the relay satellite through the relay terminal installed on it, transmits telemetry data to the relay satellite and then to the ground command and control center, realizing the support of launch vehicle TT&C. The relay terminal installed on the launch vehicle is usually composed of two parts: one is a phased array antenna installed on the surface of the launch vehicle, which is used to radiate electromagnetic waves to communicate with the relay satellite; the other is a processor installed in the instrument cabin inside the launch vehicle, which is connected to the phased array antenna through a cable and is used for data modulation and RF frequency conversion and other signal processing.

[0025] When relying on a relay satellite to provide support for launch vehicle TT&C, the relay terminal installed on the launch vehicle (hereinafter referred to as the launch vehicle-mounted relay terminal) needs to control the phased array antenna beam to point to the relay satellite after the rocket takes off, in order to realize uninterrupted communication with the relay satellite. If space-based TT&C support is provided by a geostationary orbit relay satellite, the geostationary orbit relay satellite is stationary relative to the ground, i.e. the position coordinates of the geostationary orbit relay satellite in the launch coordinate system are fixed, so the launch vehicle-mounted 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 affect the communication because the position of the geostationary orbit relay satellite does not change relative to a certain point on the rocket flight trajectory during normal flight. Some existing patents on the calculation of the pointing angle of the launch vehicle-mounted relay terminal are designed for geostationary orbit relay satellites.

[0026] Although the geostationary orbit relay satellite has the advantage of being stationary relative to the ground and can stably cover the Asia-Pacific region for a long time, the number of available geostationary orbit positions is limited, has strategic significance, and has been occupied by a large number of commercial space applications. It is very difficult to apply for a geostationary orbit position, so in recent years, the technology of medium-orbit relay satellites has been increasingly valued. Compared with geostationary orbit relay satellites, medium-orbit relay satellites have a large number of orbit positions and are relatively easy to apply for. Although a medium-orbit relay satellite is in motion relative to the ground at all times and can only cover the airspace over the Asia-Pacific region for a short time (such as a few hours), by deploying multiple medium-orbit relay satellites in an orbital plane and using a relay method, long-term coverage of the Asia-Pacific region can also be achieved.

[0027] If a launch vehicle relies on multiple medium-orbit relay satellites for space-based TT&C support, considering the probability of launch vehicle launch delay is not low and the delay time is uncertain, because the medium-orbit relay satellites are in continuous motion relative to the ground, it is impossible to pre-set which medium-orbit relay satellite the rocket-borne relay terminal communicates with during the flight before launch or installation. Only a certain medium-orbit relay satellite can be selected in real time according to a certain criterion during the rocket flight. The present application is to solve the multi-satellite selection problem faced by the launch vehicle relying on the medium-orbit relay satellite system for space-based TT&C. This selection criterion is an important innovation of the present application compared with the existing related patents.

[0028] To solve the above problems, the embodiment of the present application provides a rocket-borne relay terminal and a control method thereof.

[0029] In one embodiment, a control method of a rocket-borne relay terminal is provided. Through the control method of the rocket-borne relay terminal, the link radiation efficiency of the rocket-borne relay terminal in the direction of multiple relay satellites can be determined during the rocket flight, and then it can be determined which relay satellite the rocket-borne relay terminal should select to communicate.

[0030] Among them, referring to 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 can specifically include an antenna array, a transmitting component 211, and a wave control unit 212. The processor 220 can specifically include a digital baseband unit 221 and a control unit 222. After the processor 220 receives the rocket telemetry data, time, position, attitude, and other information transmitted by the launch vehicle 100 control system, the rocket telemetry data can be modulated by the digital baseband unit 221, then transmitted to the transmitting component 211 through the cable, and then radiated outward through the transmitting component 211. The control unit 222 in the processor 220 can select one of the multiple relay satellites, and then control the antenna beam of the phased array antenna 210 to point to the direction of the selected relay satellite through the wave control unit 212. The specific satellite selection method is the control method of the rocket-borne relay terminal 200 provided by the present application.

[0031] Specifically, referring to Figure 4 , the control method of the rocket-borne relay terminal 200 provided by the embodiment includes the following steps: Step S200, determining the positions of several relay satellites in the Earth-Centered Inertial coordinate system at the next time.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Step S500, according to the position of each relay satellite in the polar coordinate system of the launch vehicle relay terminal antenna, determine the link radiation efficiency of the phased array antenna 210 in the direction of each relay satellite.

[0040] The link radiation efficiency refers to the size of the power radiation efficiency of the launch vehicle relay terminal 200 in the microwave signal link to the relay satellite. In this embodiment, the microwave link radiation efficiency of the launch vehicle relay terminal 200 in the direction of each relay satellite can be estimated according to the position of each relay satellite in the polar coordinate system of the launch vehicle relay terminal antenna, which is used for subsequent comparison.

[0041] 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.

[0042] 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 is determined, and the relay satellite corresponding to the maximum value is determined as the target relay satellite, that is, the relay satellite in communication with the launch vehicle relay terminal 200.

[0043] Step S700, establish the communication connection between the target relay satellite and the phased array antenna 210.

[0044] After determining the target relay satellite, the communication connection between the target relay satellite and the phased array antenna 210 can be established. Specifically, the azimuth angle and the elevation angle of the target relay satellite in the polar coordinate system of the launch vehicle relay terminal antenna can be taken as the beam pointing angle of the phased array antenna 210 at the next moment, and sent to the wave control unit 212 corresponding to the phased array antenna 210, so that the wave control unit 212 controls the phased array antenna 210 to point to the target relay satellite, thereby establishing the communication connection between the target relay satellite and the phased array antenna 210.

[0045] 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.

[0046] 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: 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.

[0047] Specifically, in one embodiment, the position transformation can be performed using the following formula: 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.

[0048] The geocentric fixed coordinate system is defined as follows: the origin of the coordinate system is perpendicular to the geocenter. O e coincide, O e X eThe 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.

[0049] 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.

[0050] Specifically, in one embodiment, the position transformation can be performed using the following formula: 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.

[0051] 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 l The tangent plane that is tangent to the Earth's reference ellipsoid. O l X lThe 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.

[0052] 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.

[0053] Specifically, in one embodiment, the position transformation can be performed using the following formula: 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.

[0054] 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.

[0055] 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.

[0056] Specifically, in one embodiment, the position transformation can be performed using the following formula: 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.

[0057] 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.

[0058] 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 Z b 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 .

[0059] 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 polar coordinate system of the rocket-borne relay terminal antenna, the position conversion 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. 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.

[0060] 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 denotes the distance of the target from the origin, the azimuth angle A denotes the projection of the vector from the origin to the target on the antenna array plane and the O a X a the angle between the axes, by O a X a the axis to O a Y a the rotation direction of the axis is positive, the pitch angle E denotes the angle between the vector from the origin to the target and the antenna array plane, by the array plane towards O a Z a the rotation direction is positive.

[0061] In one embodiment, the step S500, i.e., the step of determining the link radiation efficiency of the phased array antenna 210 in the direction of each relay satellite according to the position of each relay satellite in the polar coordinate system of the satellite-borne relay terminal antenna, comprises: For each relay satellite, the link radiation efficiency in the direction of the relay satellite is determined according to the pitch angle of the relay satellite in the polar coordinate system of the satellite-borne relay terminal antenna and the distance from the relay satellite to the center of the array plane of the phased array antenna 210.

[0062] That is, in the present embodiment, the pitch angle of the relay satellite in the polar coordinate system of the satellite-borne relay terminal antenna and the distance from the relay satellite to the center of the array plane of the phased array antenna 210 can be determined, and then the signal radiation efficiency in the microwave signal link of the satellite-borne relay terminal 200 in the direction of the relay satellite, i.e., the link radiation efficiency in the direction of the relay satellite, can be calculated according to the two.

[0063] Specifically, in one embodiment, the link radiation efficiency of the relay satellite can be determined by the following formula: wherein, denotes the link radiation efficiency of the phased array antenna 210 of the satellite-borne relay terminal in the direction of a certain relay satellite, denotes the pitch angle of the relay satellite in the polar coordinate system of the satellite-borne relay terminal antenna, denotes the distance from the relay satellite to the center of the array plane of the phased array antenna 210.

[0064] 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: 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 represents the preset lower limit value of the pitch angle.

[0065] 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° .

[0066] 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.

[0067] Based on the same inventive concept, and referring to Figure 1In another embodiment, a satellite-borne relay terminal 200 is also provided, comprising a phased array antenna 210, a digital baseband unit 221 and a control unit 222, the digital baseband unit 221 and the control unit 222 are both electrically connected to the phased array antenna 210, and the digital baseband unit 221 and the control unit 222 belong to the same processor 220. The control unit 222 is configured to perform the control method of the satellite-borne relay terminal 200 as described above.

[0068] The phased array antenna 210 can specifically include an antenna array, a transmitting component 211 and a wave control unit 212. The digital baseband unit 221 can be electrically connected to the transmitting component 211 in the phased array antenna 210, and the control unit 222 can be electrically connected to the wave control unit 212 in the phased array antenna 210.

[0069] For specific content of the phased array antenna 210, the digital baseband unit 221 and the control unit 222, please refer to the specific description in the control method of the satellite-borne relay terminal 200 provided in the foregoing embodiments, which will not be repeated here.

[0070] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present disclosure.

[0071] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A control method for a rocket-borne relay terminal, characterized in that, The rocket-borne relay terminal includes a phased array antenna; the control method for the rocket-borne 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. 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, 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: 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.

9. The control method for the rocket-borne relay terminal according to claim 8, characterized in that, 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: 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.

10. The control method for the rocket-borne relay terminal according to claim 9, 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 represents the preset lower limit value of the pitch angle.

11. 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.

12. A rocket-borne relay terminal, characterized in that, The device includes a phased array antenna, a digital baseband unit, and a control unit, wherein the digital baseband unit and the control unit are electrically connected to the phased array antenna, and the control unit is configured to execute the control method of the rocket-borne relay terminal according to any one of claims 1-11.

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