Mechatronics small planar phased-array antenna satellite tracking method and device

Abstract

The invention provides a satellite tracking method and device for a mechanical-electrical integration small planar phased-array antenna, and belongs to the technical field of satellite communication. The method comprises the following steps: starting and electrifying the small planar phased-array antenna and adjusting the small planar phased-array antenna into a preparation attitude; using the central array element to complete satellite searching to obtain ephemeris information; in the satellite and satellite top-crossing tracking stage, the expected beam direction is calculated, the beam direction is controlled in a beam forming and mechanical angle compensation combined mode, and satellite and satellite tracking operation is achieved; and the antenna receives the satellite switching instruction and adjusts the satellite switching instruction to a preparation attitude, and the next round of satellite tracking operation is carried out. According to the invention, mechanical angle compensation is carried out on the wave beam by adjusting the orientation of the antenna array surface, the satellite alignment and tracking performance of the antenna in a low satellite elevation scene is improved, and the consistency of terminal communication performance in the satellite top-crossing process is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite communications, and in particular, relates to a satellite tracking method and device of a mechatronic small-sized planar phased array antenna. Background Art

[0002] In the field of satellite communications, compared with traditional high and medium orbit satellites, low-orbit satellites have the advantage of low orbital altitude, and can therefore provide greater landing signal power and stronger information transmission capabilities, which enables satellite communication terminals to obtain more diverse application services. At present, low-orbit satellite communications are gradually becoming the mainstream trend in the development of satellite communications.

[0003] However, the high-speed movement of low-orbit satellites causes the viewing angle between ground terminals and satellites to change rapidly, which requires ground antennas to frequently adjust their directions to maintain connection with satellites, increasing the complexity and difficulty of antenna tracking and placing new requirements on the alignment and tracking capabilities of ground antennas. Existing antenna alignment methods are mainly divided into mechanical servo alignment and phased array antenna beamforming alignment. Mechanical servo alignment adjusts the direction of the antenna by controlling mechanical devices (such as motors, gears, drive mechanisms, etc.) so that it is always aimed at the satellite. Phased array antenna beamforming alignment electronically adjusts the phases of multiple antenna units to form a beam pointing in a specific direction, thereby achieving fast and precise beam control.

[0004] In the low-orbit satellite communication scenario, the advantages of phased array antennas such as fast response, no mechanical wear, small size, multi-beam tracking capability, and high reliability make phased array antenna beamforming tracking an ideal choice for low-orbit satellite communication systems. However, for small planar phased array antennas, when the satellite elevation angle is small, the beam elevation angle is low, and the beamforming performance is significantly reduced, resulting in increased beam width, increased sidelobe level, increased beam pointing error, reduced antenna efficiency, and increased control complexity. This means that when the satellite is in the low elevation angle area, the antenna's tracking and tracking performance cannot meet the index requirements.

[0005] Therefore, a small planar phased array antenna alignment and tracking method is needed to improve the alignment and tracking performance under low satellite elevation conditions, to achieve high-performance alignment and tracking of terminal antennas in low-orbit satellite communication scenarios, and to ensure the consistency of terminal communication performance when the low-orbit satellite passes overhead. Summary of the invention

[0006] In view of the above problems, the present invention proposes a method and device for tracking satellites using a mechatronic small planar phased array antenna. In the low beam elevation angle scenario, the present invention uses mechanical angle compensation to adjust the antenna array orientation, increase the beam elevation angle relative to the array, and uses beam synthesis and mechanical angle compensation to ensure the antenna's tracking and tracking performance at low satellite elevation angles, and ensure the consistency of the terminal satellite communication performance during the low-orbit satellite pass.

[0007] The technical solution adopted by the present invention is:

[0008] A satellite tracking method for a mechatronic small planar phased array antenna comprises the following steps:

[0009] S1, the small planar phased array antenna is powered on, the GNSS positioning and orientation unit and the inertial navigation unit are used to obtain the antenna position information and attitude information, and the antenna fixed coordinate system and the station center coordinate system are established, and the antenna array surface is adjusted to the preparation attitude through the servo mechanism;

[0010] S2, only the central array element of the small planar phased array antenna is turned on, and other array elements are turned off, and the central array element is used to search for satellites to obtain the satellite's ephemeris information;

[0011] S3, based on the obtained satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna, obtain the beam azimuth angle Az of the desired beam pointing a and beam elevation angle El a ;

[0012] S4, according to the beam azimuth Az a and beam elevation angle El a , using a combination of beam synthesis and mechanical angle compensation to control the beam of a small planar phased array antenna to point to the satellite and complete the satellite pointing operation;

[0013] S5, when the satellite passes overhead, the beam pointing is controlled by using a satellite tracking method that combines beam synthesis and mechanical angle compensation to achieve satellite tracking.

[0014] Furthermore, the station center coordinate system in step S1 is the northeast celestial coordinate system of the location of the small planar phased array antenna, and the preparation posture is a state in which the antenna array surface coincides with the local horizontal plane.

[0015] Furthermore, the central array element in step S2 is an omnidirectional antenna, and the central array element refers to an antenna array element in the small planar phased array antenna that is closest to the geometric center of the phased array antenna;

[0016] The rear end of the small planar phased array antenna is connected to a communication terminal. The communication terminal obtains the satellite's ephemeris information by parsing the received satellite broadcast information, and sends the ephemeris information to the small planar phased array antenna.

[0017] Furthermore, the specific method of step S4 is:

[0018] S41, considering the beam elevation angle El a and a predetermined angle compensation threshold El 0t to determine whether mechanical angle compensation is required;

[0019] S42, if El a <El 0t , mechanical angle compensation is performed, and the satellite alignment operation is completed by using the combined satellite alignment method of mechanical angle compensation and beamforming; specifically:

[0020] S421, the small planar phased array antenna obtains the required rotation angle of the antenna array surface based on the preset satellite mechanical angle compensation mode, and rotates the antenna array surface direction accordingly;

[0021] S422, recalculate the desired beam azimuth Az a and beam elevation angle El a ;

[0022] S423, using beam synthesis to control the beam pointing to the new beam azimuth angle Az a and beam elevation angle El a ;

[0023] S43, if El a ≥El 0t , there is no need for mechanical angle compensation. The small planar phased array antenna directly uses beam synthesis to control the beam pointing to the satellite and complete the satellite operation.

[0024] Furthermore, the specific method of step S5 is:

[0025] S51, at each time t, based on the satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna, obtain the satellite's station center coordinate system elevation angle El n (t);

[0026] S52, when the satellite passes overhead, the small planar phased array antenna preferentially uses beam synthesis to control the beam pointing to track the satellite and calculates the satellite's beam elevation angle El at each moment t a (t);

[0027] S53, at each moment t, consider the beam elevation angle El a (t) and angle compensation threshold El 0t The relationship between the two determines whether to use pure beam synthesis or mechanical angle compensation to achieve satellite tracking:

[0028] If Ela (t) <El 0t , then the antenna array direction is rotated based on the preset tracking mechanical angle compensation scheme to perform mechanical angle compensation to ensure El a (t) not less than El 0t ;

[0029] If El a (t)3El 0t , the antenna array is kept stationary, and the beam direction is controlled by beam synthesis to achieve satellite tracking;

[0030] S54, at each moment t, consider the elevation angle El of the satellite's station center coordinate system n (t) and tracking compensation cut-off threshold El nt relationship, when El n (t) <El nt When the mechanical tracking compensation is stopped.

[0031] A mechatronic small-sized planar phased array antenna satellite tracking device, comprising:

[0032] The antenna array plane realizes the signal receiving and transmitting function between the antenna and the satellite. Multiple microstrip antenna arrays are arranged to achieve high normal gain and directional beam synthesis of the antenna through a planar array.

[0033] The inertial navigation unit is strapdown-mounted to the antenna array to obtain the attitude of the antenna array;

[0034] GNSS positioning and orientation unit, used to determine the position and heading angle of the antenna array;

[0035] The control unit obtains a beam pointing instruction based on the current antenna array direction obtained by the inertial navigation unit and the GNSS positioning and orientation unit and in combination with the satellite ephemeris information; controls the antenna array to complete beam synthesis according to any of the above methods, and controls the servo unit to perform mechanical angle compensation of the antenna array;

[0036] The servo unit realizes the rotation of the antenna array according to the mechanical angle compensation instruction of the antenna array issued by the control unit, so as to compensate the mechanical angle of the antenna array during satellite tracking.

[0037] Furthermore, it also includes a communication terminal for completing the capture and synchronization of satellite broadcast signals, as well as the parsing of ephemeris information, and sending the ephemeris information to the control unit.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The present invention adjusts the antenna array orientation to perform mechanical angle compensation on the beam, thereby improving the antenna alignment and tracking performance in low satellite elevation angle scenarios.

[0040] 2. Compared with pure mechanical servo antennas, the present invention can achieve rapid beam pointing adjustment and is suitable for high-speed low-orbit satellite communication scenarios; compared with the pure electric scanning method of planar phased array antenna satellite tracking, the present invention can improve the beam gain performance in low satellite elevation angle scenarios.

[0041] In summary, the present invention realizes high-performance rapid satellite alignment and tracking of the terminal antenna in a satellite communication scenario, and ensures the consistency of the terminal satellite communication performance during the satellite pass. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the connection between the mechatronic small planar phased array antenna satellite tracking device and the supporting terminal in an embodiment of the present invention.

[0043] Figure 2 It is a structural schematic diagram of a mechatronic small planar phased array antenna satellite tracking device.

[0044] Figure 3 It is a flow chart of a satellite tracking method of a mechatronic small planar phased array antenna in an embodiment of the present invention.

[0045] Figure 4 It is a schematic diagram of the coordinate system used in the embodiment of the present invention.

[0046] Figure 5 It is a flow chart of beam synthesis and mechanical angle compensation joint alignment in an embodiment of the present invention.

[0047] Figure 6 It is a flow chart of beam synthesis and mechanical angle compensation joint tracking in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0049] A mechatronic small planar phased array antenna satellite tracking method, the method uses beam synthesis and mechanical angle compensation to achieve small planar phased array antenna satellite tracking, including the following steps:

[0050] S1, the small planar phased array antenna is powered on, the GNSS positioning and orientation unit and the inertial navigation unit are used to obtain the antenna position information and attitude information, and the antenna fixed coordinate system and the station center coordinate system are established, and the antenna array surface is adjusted to the preparation attitude through the servo mechanism;

[0051] S2, only the central antenna element of the small planar phased array antenna is turned on, and other elements are turned off, and the central element is used to search for satellites to obtain the ephemeris information of the star;

[0052] S3, based on the obtained satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna, obtain the beam azimuth angle Az of the desired beam pointing a and beam elevation angle El a ;

[0053] S4, based on the beam azimuth and elevation, uses beam synthesis and mechanical angle compensation to control the small planar phased array antenna beam to point to the satellite, completing the satellite pointing operation;

[0054] S5, when the satellite passes overhead, the beam pointing is controlled by using a satellite tracking method combining beam synthesis and mechanical angle compensation to achieve satellite tracking;

[0055] S6, receiving the satellite cutting command sent by the satellite, obtaining the beam information of the subsequent satellite, adjusting the small planar phased array antenna to the ready posture, and repeating the operations of steps S2 to S6.

[0056] A mechatronic small-sized planar phased array antenna star tracking device comprises an antenna array, an inertial navigation unit, a GNSS positioning and orientation unit, a control unit, and a servo unit; wherein:

[0057] The antenna array realizes the signal receiving and transmitting function between the antenna and the satellite. Multiple microstrip antenna arrays are arranged to realize the normal high gain design and directional beam synthesis of the antenna through the planar array method.

[0058] The inertial navigation unit is strapdown-installed with the antenna array to obtain the attitude of the antenna array;

[0059] The GNSS positioning and orientation unit is used to determine the position and heading angle of the antenna array;

[0060] The control unit obtains the beam pointing instruction based on the current antenna array direction obtained by the inertial navigation unit and the GNSS positioning and orientation unit, combined with the satellite ephemeris information, controls the antenna array to complete beam synthesis, and controls the servo unit to rotate the antenna array to perform mechanical angle compensation;

[0061] The servo unit realizes the rotation of the antenna array according to the mechanical angle compensation instruction of the antenna array issued by the control unit to meet the mechanical angle compensation requirements of the antenna array during satellite tracking.

[0062] When in use, the device needs to be connected to a matching communication terminal, which is used to capture and synchronize satellite broadcast signals, parse ephemeris information, and send the ephemeris information to the control unit.

[0063] like Figure 1 As shown, the communication terminal 101 provides the necessary information required to realize the satellite alignment and tracking functions of the planar phased array antenna 102, has the ability to parse satellite communication system information, can complete the initial capture of the satellite broadcast signal received by the planar phased array antenna 102, and demodulate and parse the broadcast information to obtain the satellite's ephemeris information, and send the ephemeris information to the planar phased array antenna 102, in preparation for the next step of completing the satellite alignment and tracking process. It should be understood that the communication terminal 101 is not a necessary device for realizing the satellite alignment and tracking functions of the planar phased array antenna 102. In other optional embodiments, a satellite signal demodulation processing module can be provided at the planar phased array antenna 102 to realize the initial capture of the satellite broadcast signal and the parsing and acquisition of the satellite broadcast ephemeris.

[0064] like Figure 2 As shown, the planar phased array antenna 102 is mainly composed of an antenna array surface 102-1, a GNSS positioning and orientation unit 102-2, a servo unit 102-3, a control unit 102-4 and an inertial navigation unit 102-5.

[0065] The antenna array 102-1 is used to realize the signal receiving and transmitting function between the antenna and the satellite. On the antenna array, multiple microstrip antenna arrays are arranged to form a beam pointing to a specific direction by receiving the phase information of each array unit sent by the control unit 102-4.

[0066] The GNSS positioning and orientation unit 102-2 realizes the antenna position longitude λ by installing two navigation and positioning modules A , Latitude L A , height H A The determination of the antenna heading angle (the angular offset of the antenna relative to true north), the GNSS positioning and orientation unit is not limited to the Beidou navigation system or the GPS navigation system or other available navigation systems;

[0067] The servo unit 102-3 receives the antenna array surface mechanical angle compensation instruction issued by the control unit 102-4, and realizes the rotation of the antenna array surface 102-1 on the pitch axis and the azimuth axis according to the required angle, thereby meeting the demand for mechanical angle compensation of the antenna array surface 102-1 during satellite tracking;

[0068] The inertial navigation unit 102-5 is strapdown-mounted with the antenna array 102-1 to determine the attitude of the antenna array relative to the station center coordinate system at each moment. The origin of the station center coordinate system is located at the geometric center of the antenna array, and its coordinate axis points to coincide with the local northeast sky direction.

[0069] The control unit 102-4 is responsible for the data collection, calculation and processing, and instruction generation tasks of the entire planar phased array antenna 102. It calculates the orbit of the target satellite by receiving the ephemeris information from the supporting communication terminal, and calculates the position and heading information of the current antenna array by receiving the positioning and orientation information from the GNSS positioning and orientation unit. It calculates the attitude information of the current antenna array by receiving the specific force and angular velocity information of the inertial navigation unit. According to the star alignment and tracking algorithm stored in the control unit 102-4, it calculates the beam pointing angle required for star alignment or tracking at the current moment and the angle required for mechanical compensation of the antenna array, controls the antenna array to complete beam synthesis, and controls the servo unit to rotate to realize beam pointing in the desired direction.

[0070] Based on the antenna position and orientation information provided by the GNSS positioning and orientation unit 102-2, combined with the specific force and attitude angular velocity information output by the inertial navigation unit 102-5, and in conjunction with a corresponding filtering algorithm, combined navigation of multi-source navigation data fusion can be implemented to improve the estimation accuracy of the position and attitude information of the antenna array 102-1. The filtering algorithm can be, but is not limited to, an algorithm based on a Kalman filter or other online optimal estimation algorithms.

[0071] It should be understood that the device may further include additional frames not shown and / or the frames shown may be omitted, and the components shown may be implemented by hardware, software or a combination thereof, and the scope of the present application is not limited in this respect.

[0072] like Figure 3 As shown, the satellite tracking method of the mechatronic small planar phased array antenna includes the following steps:

[0073] S1, the small planar phased array antenna is powered on, the GNSS positioning and orientation unit and the inertial navigation unit are used to obtain the antenna position information and attitude information, and the antenna fixed coordinate system and the station center coordinate system are established, and the antenna array surface is adjusted to the ready attitude through the servo mechanism.

[0074] refer to Figure 4 In step S1, the station center coordinate system is the local northeast celestial coordinate system, represented by n, and the coordinate axis is OX n Y n Z n , the origin of the coordinate system is at the geometric center of the antenna array, X n The Y axis points to the local geographic east. n The axis points to the local geographic north, Zn The axis points to the sky and is aligned with the X n Y n The two axes form a right-hand system; the antenna fixed-joint coordinate system is the upper left coordinate system before the antenna is fixed, represented by a, and the coordinate axis is OX a Y a Z a , whose coordinate origin is at the geometric center of the antenna array, X a The axis coincides with the long axis of the antenna array, Y a The axis coincides with the short axis of the antenna array and points to the left. a The axis points to the sky and is aligned with the X a Y a The two axes form a right-hand system. The inertial navigation unit is strapdown-mounted to the antenna array, and its coordinate axis coincides with the axis of the antenna fixed-link coordinate system. Therefore, the data measured by the inertial navigation unit can be used to calculate in real time the attitude of the antenna fixed-link coordinate system relative to the station center coordinate system. Furthermore, the attitude conversion matrix from the n system to the a system is used The GNSS positioning and orientation unit baseline coincides with the long axis of the antenna array, that is, the X coordinate system fixed to the antenna a The GNSS positioning and orientation unit can be used to measure the deflection heading angle of the antenna's long axis in the local horizontal plane. Figure 4 The Earth-centered Earth-fixed system ECEF is also defined, represented by e, with the coordinate axis OX e Y e Z e , the origin is the center of the earth, Z e The axis coincides with the earth's axis, X e The Y axis lies in the equatorial plane and points toward the prime meridian. e Axis and X e Z e The axes are perpendicular and form a right-handed coordinate system.

[0075] The servo unit of the planar phased array antenna is divided into the pitch axis and the azimuth axis, such as Figure 4 As shown, the azimuth axis is colinear with the antenna support 401, and the antenna can rotate around the axis to change the azimuth angle of its array surface. The elevation axis coincides with the short axis of the antenna array surface, and the antenna can rotate around the axis to change the elevation angle of its array surface.

[0076] In step S1, the posture prepared is the vector from the center of the earth to the geometric center of the antenna array and the antenna fixed coordinate system OZ a The axes of the antenna are aligned to ensure that the antenna array is in a horizontal state. Furthermore, the antenna array can be adjusted to the ready attitude by the following steps:

[0077] Through the GNSS positioning and orientation unit, using the GNSS positioning algorithm, the position vector of the antenna ECEF system at the initial moment can be obtained Then we can get the longitude λ of the location of the antennaA , Latitude L A , height H A Based on the latitude, longitude and altitude information, the coordinate transformation matrix from the ECEF system e to the station center coordinate system n can be obtained As shown below:

[0078]

[0079] The coordinate transformation matrix of the antenna fixed coordinate system a relative to the station center coordinate system n can be obtained in real time by using the data measured by the inertial navigation unit. Furthermore, the coordinate transformation matrix from the ECEF system to the antenna fixed connection can be obtained as Then the pointing vector from the center of the earth to the geometric center of the antenna array is Under the fixed connection of the antenna, it can be expressed as:

[0080]

[0081] Azimuth angle Az under antenna fixed connection a0 and elevation angle El a0 It can be obtained by the following formula:

[0082]

[0083] To adjust the antenna array from the power-on attitude to the standby attitude, the antenna array can be rotated around the azimuth axis Az a0 Angle, then rotate El around the pitch axis c =min{90°-El a0 ,El cmax} angle, where El cmax It is the maximum angle that the antenna servo mechanism pitch axis can rotate, with no positive or negative sign distinction. It should be noted that the rotation angle El here c There are positive and negative points. When the rotation angular velocity vector is a When the axes coincide in the positive direction, El c is positive, otherwise it is negative.

[0084] In other embodiments, the preparation posture may also be the antenna array posture formed by rotating the pitch axis / azimuth axis of the servo unit through a specific angle. The corresponding angle may be determined by the line of sight azimuth of the satellite in the known communication satellite constellation so as to make the compensation angle required for mechanical compensation as small as possible.

[0085] S2, only the central antenna element of the small planar phased array antenna is turned on, and other elements are turned off, and the central element is used to search for satellites to obtain the ephemeris information of the star.

[0086] In step S2, the central array element is an omnidirectional antenna, and the central array element refers to an antenna array element in a small planar phased array antenna that is closest to the geometric center of the phased array antenna, and the satellite is the satellite corresponding to the beam that can provide the maximum receiving power for the central array element. The process of obtaining satellite ephemeris can be completed by the supporting communication terminal 101. Further, the process of obtaining ephemeris depends on the following steps:

[0087] The communication terminal controls the small planar phased array antenna to scan within a given time-frequency grid;

[0088] The terminal captures the beam that can provide the maximum receiving power, and the communication terminal achieves downlink synchronization based on the broadcast signal;

[0089] The terminal obtains the satellite's ephemeris information based on the satellite broadcast information analysis;

[0090] The terminal sends the ephemeris information to the planar phased array antenna.

[0091] S3, based on the obtained satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna, obtain the beam azimuth angle Az of the desired beam pointing a and beam elevation angle El a .

[0092] In step S3, after receiving the satellite ephemeris information, the planar phased array control unit 102-4 takes the current time as the initial time and calculates the position vector of the satellite in the ECEF system at the initial time according to the ephemeris information. Furthermore, the position information of the antenna can be obtained by the GNSS positioning and orientation unit. Specifically, the position vector of the antenna in the ECEF system at the initial moment can be obtained by the GNSS positioning and orientation unit using the GNSS positioning algorithm. Then we can get the longitude λ of the location of the antenna A , Latitude L A , height H A Based on the latitude and longitude information, the coordinate transformation matrix from the ECEF system e to the station center coordinate system n in step S1 can be obtained As shown below:

[0093]

[0094] The coordinate transformation matrix of the antenna fixed coordinate system a relative to the station center coordinate system n can be obtained in real time by using the data measured by the inertial navigation unit. Furthermore, the coordinate transformation matrix from the ECEF system to the antenna fixed connection can be obtained as Therefore, the pointing vector of the satellite under the fixed connection of the antenna is It is expressed as:

[0095]

[0096] The beam azimuth angle Az of the desired beam pointing in step S3 a and beam elevation angle El a It can be obtained by the following formula:

[0097]

[0098] S4, according to the beam azimuth and elevation, uses a combination of beam synthesis and mechanical angle compensation to control the small planar phased array antenna beam pointing to the satellite to complete the satellite operation.

[0099] In step S4, beam synthesis and mechanical angle compensation are combined to control the planar phased array antenna beam pointing to the satellite. The purpose is to improve the antenna satellite performance in low satellite elevation angle scenarios by mechanically rotating the antenna array and coordinating electronic scanning beam synthesis. Figure 5 As shown, it includes the following specific steps:

[0100] S41, considering the beam elevation angle El a and a predetermined angle compensation threshold El 0t to determine whether mechanical angle compensation is required;

[0101] S42, if El a <El 0t , mechanical angle compensation is performed, and the satellite alignment operation is completed by using a combined satellite alignment method of mechanical angle compensation and beamforming;

[0102] S43, if El a ≥El 0t , there is no need for mechanical angle compensation. The small planar phased array antenna directly uses beam synthesis to control the beam pointing to the satellite and complete the satellite operation.

[0103] In step S41, the angle compensation threshold El 0t Determine whether mechanical angle compensation is needed during satellite alignment. The threshold value should be determined based on the beam gain curve of the phased array antenna. Optionally, assume that the beam gain of the phased array antenna decreases significantly when the elevation angle is lower than 15°, and the minimum antenna operating elevation angle required by the mission is El min =10°, then in order to ensure the satellite gain of the antenna at an elevation angle of 10°, El 0t =15°.

[0104] In step S42, the mechanical angle compensation and beamforming joint alignment method includes the following specific steps:

[0105] S421, the small planar phased array antenna obtains the required rotation angle of the antenna array surface based on the preset satellite mechanical angle compensation mode, and rotates the antenna array surface direction accordingly;

[0106] S422, recalculate the desired beam azimuth Az according to step S3 a and beam elevation angle El a ;

[0107] S423, using beam synthesis to control the beam pointing to the new beam azimuth angle Az a and beam elevation angle El a .

[0108] Optionally, the following method is provided to calculate the angle of rotation required for the antenna array surface in step S421:

[0109] When the antenna is in the ready position, first rotate Az around the azimuth axis of the servo unit. a Angle, and then increase the beam elevation angle El around the pitch axis a The direction of rotation min{El 0t -El a ,El cmax -El c} angle, where El c is the angle through which the servo mechanism pitch axis has rotated when the antenna array is adjusted from the power-on posture to the ready posture in step S1, cmax It is the maximum angle that the antenna servo mechanism pitch axis can rotate.

[0110] S5, when the satellite passes overhead, the beam pointing is controlled by using a satellite tracking method that combines beam synthesis and mechanical angle compensation to achieve satellite tracking.

[0111] In step S5, during the satellite passing overhead, a satellite tracking method combining beam synthesis and mechanical angle compensation is used to control the beam pointing of the planar phased array antenna to achieve satellite tracking, such as Figure 6 As shown, it includes the following specific steps:

[0112] S51, at each time t, based on the satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna, obtain the satellite's station center coordinate system elevation angle El n (t);

[0113] S52, when the satellite passes overhead, the small planar phased array antenna preferentially uses beam synthesis to control the beam pointing to track the satellite and calculates the satellite's beam elevation angle El at each moment t a (t);

[0114] S53, at each moment t, consider the beam elevation angle El a (t) and angle compensation threshold El 0tand determine whether to use pure beam synthesis or mechanical angle compensation to achieve satellite tracking;

[0115] S54, at each moment t, consider the elevation angle El of the satellite's station center coordinate system n (t) and tracking compensation cut-off threshold El nt relationship, when El n (t) <El nt When the mechanical tracking compensation is stopped.

[0116] Furthermore, in step S51, the elevation angle El of the satellite in the station center coordinate system n (t) can be calculated by the following steps:

[0117] The position vector of the satellite at time t in the ECEF system is calculated using the satellite ephemeris information

[0118] Use the GNSS positioning and orientation unit to obtain the longitude λ of the antenna location at time t A , Latitude L A , height H A , and based on the longitude, latitude and height information, the coordinate transformation matrix from the ECEF system to the station center coordinate system is obtained

[0119] The position vector of the satellite in the station center coordinate system can be expressed as

[0120] The elevation angle of the satellite in the station center coordinate system can be obtained

[0121] In step S52, the satellite beam elevation angle El is calculated at each time t. a The method of (t) is the same as step S3.

[0122] In step S53, the specific steps of determining whether to use mechanical angle compensation to implement satellite tracking are as follows:

[0123] S531, if El a (t) <El 0t Based on the preset tracking mechanical angle compensation scheme, the antenna array direction is rotated to perform mechanical angle compensation to ensure El a (t) not less than El 0t ;

[0124] S532, if El a (t)3El 0t , keep the antenna array still, use beam synthesis to control the beam pointing and achieve satellite tracking.

[0125] Furthermore, an example of the tracking mechanical angle compensation scheme preset in step S531 is as follows:

[0126] Consider dividing the time into a series of time slots of equal length, and the mechanical angle compensation of the antenna array uses one time slot as the minimum control unit; within a minimum control unit, if El a (t) <El 0t , then keep the azimuth axis angle of the antenna servo unit unchanged, adjust the pitch axis, so that the antenna array increases El around the servo unit pitch axis a (t) is rotated by 2° and the adjusted El is calculated a (t); if at this time El a (t)3El 0t , then in the next control unit, the antenna array direction is kept unchanged; otherwise, the next control unit uses the same method as step S3 to calculate the current Az a (t), and reduce the antenna array around the servo unit azimuth axis by Az a (t) and rotate 2°, and continue to adjust the pitch axis to increase El a (t) is rotated 2° until El is satisfied. a (t)3El 0t , or meet the tracking compensation cutoff threshold condition of S54, that is, El n (t) <El nt until.

[0127] In step S54, the elevation angle El of the satellite station center coordinate system at each time t is n (t) The calculation method is the same as that described in step S51; Tracking compensation cutoff threshold El nt The threshold for stopping mechanical angle compensation during satellite tracking is given. The specific value is given by the mission requirements to ensure that the satellite elevation angle is not less than El nt Within the range of , the beam gain meets the task requirements; further, by setting El nt The value of can also achieve a trade-off between the antenna performance at low satellite elevation angles and the satellite cutting efficiency. nt When the value is small, the gain performance of the antenna beam can be guaranteed when the satellite is at a lower elevation angle through the mechanical angle compensation of the antenna array. However, the pitch axis rotation angle generated by the array to achieve mechanical angle compensation will increase accordingly. After the antenna receives the satellite cutting command sent by the satellite, the time required for it to adjust to the preparation attitude will increase accordingly. At this time, the beam performance of the satellite at a low elevation angle is guaranteed at the expense of the antenna cutting efficiency. On the contrary, when El nt When the value is large, the beam performance of the satellite at low elevation angles will be sacrificed and the antenna cutting efficiency will be improved.

[0128] S6, receiving the satellite cutting command sent from the satellite, obtaining the beam information of the subsequent satellite, adjusting the small planar phased array antenna to the ready posture, and repeating the operations from S2 to S6.

[0129] In summary, the present invention adjusts the antenna array orientation to mechanically compensate the beam angle, thereby improving the antenna tracking and tracking performance in low satellite elevation scenarios, and ensuring the consistency of terminal communication performance during satellite overpasses. Compared with pure mechanical servo tracking, the present invention can achieve rapid beam pointing adjustment; compared with pure electric scanning tracking, the present invention can improve beam gain in low satellite elevation scenarios.

[0130] It should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A satellite tracking method for a mechatronic small planar phased array antenna, characterized in that: The following steps are involved: S1, the small planar phased array antenna is powered on, the GNSS positioning and orientation unit and the inertial navigation unit are used to obtain the antenna position information and attitude information, and the antenna fixed coordinate system and the station center coordinate system are established, and the antenna array surface is adjusted to the preparation attitude through the servo mechanism; S2, only the central array element of the small planar phased array antenna is turned on, and other array elements are turned off, and the central array element is used to search for satellites to obtain the satellite's ephemeris information; S3, based on the obtained satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna, obtain the beam azimuth angle Az of the desired beam pointing a and beam elevation angle El a ; S4, according to the beam azimuth Az a and beam elevation angle El a , using a combination of beam synthesis and mechanical angle compensation to control the beam of a small planar phased array antenna to point to the satellite and complete the satellite pointing operation; S5, when the satellite passes overhead, the beam pointing is controlled by using a satellite tracking method that combines beam synthesis and mechanical angle compensation to achieve satellite tracking.

2. The satellite tracking method of a mechatronic small planar phased array antenna according to claim 1, characterized in that: The station center coordinate system in step S1 is the northeast celestial coordinate system of the location of the small planar phased array antenna, and the preparation posture is a state in which the antenna array surface coincides with the local horizontal plane.

3. The satellite tracking method of a mechatronic small planar phased array antenna according to claim 1, characterized in that: The central array element in step S2 is an omnidirectional antenna, and the central array element refers to an antenna array element in a small planar phased array antenna that is closest to the geometric center of the phased array antenna; The rear end of the small planar phased array antenna is connected to a communication terminal. The communication terminal obtains the satellite's ephemeris information by parsing the received satellite broadcast information, and sends the ephemeris information to the small planar phased array antenna.

4. The satellite tracking method of a mechatronic small planar phased array antenna according to claim 1, characterized in that: The specific method of step S4 is: S41, considering the beam elevation angle El a and a predetermined angle compensation threshold El 0t to determine whether mechanical angle compensation is required; S42, if El a <El 0t , mechanical angle compensation is performed, and the satellite alignment operation is completed by using the combined satellite alignment method of mechanical angle compensation and beamforming; specifically: S421, the small planar phased array antenna obtains the required rotation angle of the antenna array surface based on the preset satellite mechanical angle compensation mode, and rotates the antenna array surface direction accordingly; S422, recalculate the desired beam azimuth Az a and beam elevation angle El a ; S423, using beam synthesis to control the beam pointing to the new beam azimuth angle Az a and beam elevation angle El a ; S43, if El a 3El 0t , there is no need for mechanical angle compensation. The small planar phased array antenna directly uses beam synthesis to control the beam pointing to the satellite and complete the satellite operation.

5. The satellite tracking method of a mechatronic small planar phased array antenna according to claim 1, characterized in that: The specific method of step S5 is: S51, at each time t, based on the satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna, obtain the satellite's station center coordinate system elevation angle El n (t); S52, when the satellite passes overhead, the small planar phased array antenna preferentially uses beam synthesis to control the beam pointing to track the satellite and calculates the satellite's beam elevation angle El at each moment t a (t); S53, at each moment t, consider the beam elevation angle El a (t) and angle compensation threshold El 0t The relationship between the two determines whether to use pure beam synthesis or mechanical angle compensation to achieve satellite tracking: If El a (t) <El 0t , then the antenna array direction is rotated based on the preset tracking mechanical angle compensation scheme to perform mechanical angle compensation to ensure El a (t) not less than El 0t ; If El a (t)3El 0t , the antenna array is kept stationary, and the beam direction is controlled by beam synthesis to achieve satellite tracking; S54, at each moment t, consider the elevation angle El of the satellite's station center coordinate system n (t) and tracking compensation cut-off threshold El nt relationship, when El n (t) <El nt When the mechanical tracking compensation is stopped.

6. A mechatronic small-scale planar phased array antenna satellite tracking device, characterized in that: include: The antenna array plane realizes the signal receiving and transmitting function between the antenna and the satellite. Multiple microstrip antenna arrays are arranged to achieve high normal gain and directional beam synthesis of the antenna through a planar array. The inertial navigation unit is strapdown-mounted to the antenna array to obtain the attitude of the antenna array; GNSS positioning and orientation unit, used to determine the position and heading angle of the antenna array; A control unit, based on the current antenna array face pointing obtained by the inertial navigation unit and the GNSS positioning and orientation unit, combined with the satellite ephemeris information, obtains a beam pointing instruction; according to the method described in any one of claims 1 to 5, controls the antenna array face to complete beam synthesis, and controls the servo unit to perform mechanical angle compensation of the antenna array face; The servo unit realizes the rotation of the antenna array according to the mechanical angle compensation instruction of the antenna array issued by the control unit, so as to compensate the mechanical angle of the antenna array during satellite tracking.

7. The mechatronic small-sized planar phased array antenna satellite tracking device according to claim 6, characterized in that: It also includes a communication terminal for completing the capture and synchronization of satellite broadcast signals, as well as the parsing of ephemeris information, and sending the ephemeris information to the control unit.

Images