Mechatronic small planar phased array antenna satellite tracking method and device

Abstract

The application provides a kind of electromechanical integration small planar phased array antenna star tracking method and device, belongs to satellite communication technical field.The method of the application includes: small planar phased array antenna power-on and adjusts to be ready for the attitude;Utilize central array element to complete star search, obtain ephemeris information;In the stage of tracking star and satellite over the top, calculate the expected beam pointing, control beam pointing by the joint mode of beam synthesis and mechanical angle compensation, realize the operation of tracking star;Antenna receives cut star instruction and adjusts to be ready for the attitude, carries out the next round of tracking star operation.The application realizes the improvement of antenna tracking performance in low satellite elevation angle scene by adjusting the orientation of antenna array to mechanically compensate the beam, ensures the consistency of terminal communication performance in the process of satellite over the top.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of satellite communication, and particularly relates to a method and device for tracking a satellite by a small planar electromechanical phased array antenna. BACKGROUND

[0002] In the field of satellite communication, compared with traditional high-orbit satellites, low-orbit satellites have the advantage of low orbit height, and thus can provide greater signal power on the ground and stronger information transmission capacity, which enables satellite communication terminals to obtain more diversified application services. At present, low-orbit satellite communication has gradually become the mainstream trend in the development of the field of satellite communication.

[0003] However, the high-speed movement of low-orbit satellites causes the angle of view of the ground terminal and the satellite to change rapidly, which leads to the need for the ground antenna to frequently adjust the direction to maintain the connection with the satellite, increasing the complexity and difficulty of antenna tracking, and putting forward new requirements for the satellite tracking and tracking capability of the ground antenna. The existing satellite tracking methods are mainly divided into mechanical servo satellite tracking and phased array antenna beam synthesis satellite tracking. Mechanical servo satellite tracking adjusts the direction of the antenna by controlling mechanical devices (such as motors, gears, driving mechanisms, etc.) to make it always point to the satellite. Phased array antenna beam synthesis satellite tracking adjusts the phase of multiple antenna elements by electronic means to form a beam pointing to a specific direction, thereby realizing rapid and accurate beam control.

[0004] In the low-orbit satellite communication scenario, the advantages of phased array antenna, such as rapid response, no mechanical wear, small size, multi-beam satellite tracking capability, high reliability, etc., make phased array antenna beam synthesis satellite 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 beam synthesis performance is significantly reduced, which may cause problems such as increased beam width, increased sidelobe level, increased beam pointing error, reduced antenna efficiency, and increased control complexity. This makes it impossible for the satellite to achieve the index requirements in the low-elevation angle region.

[0005] Therefore, a small planar phased array antenna satellite tracking and tracking method is needed to improve the satellite tracking and tracking performance under low satellite elevation angle conditions, realize high-performance satellite tracking and tracking of terminal antennas in the low-orbit satellite communication scenario, and ensure the consistency of terminal communication performance during the over-the-top process of low-orbit satellites. SUMMARY

[0006] To solve the above problems, the application provides a kind of electromechanical integration small planar phased array antenna satellite tracking method and device.The application uses mechanical angle compensation to adjust the orientation of antenna array in low beam elevation angle scene, increases the elevation angle of beam relative to array, uses the joint mode of beam synthesis and mechanical angle compensation to ensure the satellite tracking performance of antenna in low satellite elevation angle, and ensures the consistency of terminal satellite communication performance during low-orbit satellite overtop process.

[0007] The technical scheme adopted by the application is:

[0008] An electromechanical integration small planar phased array antenna satellite tracking method 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 antenna position information and attitude information, and an antenna fixed coordinate system and a station-centered coordinate system are established, and the antenna array is adjusted to a preparation posture by a 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, satellite search is performed by using the central array element, and satellite ephemeris information is obtained;

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

[0012] S4, according to the beam azimuth Az a and the beam elevation angle El a , the beam pointing satellite is controlled by using the joint mode of beam synthesis and mechanical angle compensation, and the satellite tracking operation is completed;

[0013] S5, during the satellite overtop process, the beam pointing is controlled by using the joint satellite tracking mode of beam synthesis and mechanical angle compensation, so as to realize satellite tracking.

[0014] Further, the station-centered coordinate system in step S1 is the northeast celestial coordinate system of the position where the small planar phased array antenna is located, and the preparation posture is the state that the antenna array is coincident with the local horizontal plane.

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

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

[0017] Further, the specific way of step S4 is:

[0018] S41, considering the relationship between the beam elevation angle El and the pre-given angle compensation threshold El to determine whether mechanical angle compensation is needed; a 0t

[0019] S42, if El a < El 0t , mechanical angle compensation is performed, and satellite pointing is completed by using the combined satellite pointing mode of mechanical angle compensation and beam synthesis; specifically:

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

[0021] S422, the expected beam azimuth angle Az a and the beam elevation angle El a are recalculated;

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

[0023] S43, if El a ≥ El 0t , mechanical angle compensation is not needed, and the small planar phased array antenna directly uses the beam synthesis mode to control the beam pointing to the satellite to complete satellite pointing.

[0024] Further, the specific way of step S5 is:

[0025] S51, at each time t, the satellite station coordinate system elevation angle El n (t) is obtained based on the satellite ephemeris and the position information and coordinate system information of the small planar phased array antenna;

[0026] S52, during the satellite overhead process, the small planar phased array antenna preferentially uses the beam synthesis mode to control the beam pointing for satellite tracking, and the satellite beam elevation angle El a (t) is calculated at each time t;

[0027] S53, at each time t, the relationship between the beam elevation angle El a (t) and the angle compensation threshold El 0t is considered to determine whether to use pure beam synthesis or auxiliary mechanical angle compensation to realize satellite tracking:

[0028] if El​​a (t)<El 0t , then the antenna array surface is rotated to the mechanical angle compensation scheme based on the preset tracking mechanical angle compensation scheme to ensure that El a (t) is not less than El 0t .

[0029] If El a (t) is greater than 3El 0t , the antenna array surface is kept stationary, and the beam pointing is controlled by using beam synthesis to realize satellite tracking.

[0030] S54, at each time t, considering the satellite's topocentric coordinate system elevation angle El n (t) and the relationship between the tracking compensation cutoff threshold El nt , when El n (t) is less than El nt , stop the mechanical tracking compensation.

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

[0032] An antenna array surface realizes signal transmission and reception between the antenna and the satellite, a plurality of microstrip antenna arrays are arranged, and the normal high gain and directional beam synthesis of the antenna are realized by means of planar array;

[0033] An inertial navigation unit is connected in series with the antenna array surface and is used to obtain the attitude of the antenna array surface;

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

[0035] A control unit obtains the beam pointing instruction according to the current antenna array pointing obtained by the inertial navigation unit and the GNSS positioning and orientation unit, combines satellite ephemeris information, controls the antenna array surface to complete beam synthesis according to any one of the above methods, and controls a servo unit to perform mechanical angle compensation of the antenna array surface;

[0036] A servo unit realizes the rotation of the antenna array surface according to the mechanical angle compensation instruction of the antenna array surface issued by the control unit, and realizes the compensation of the mechanical angle of the antenna array surface when tracking the satellite.

[0037] Further, a communication terminal is further included for completing satellite broadcast signal acquisition, synchronization, and ephemeris information analysis, and issuing ephemeris information to the control unit.

[0038] Compared with the prior art, the beneficial effects of the present application are:

[0039] 1. The present application adjusts the antenna array surface orientation to mechanically compensate the beam, and improves the antenna satellite tracking performance in the low satellite elevation angle scene.

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

[0041] In summary, the application realizes high-performance and rapid satellite pointing and tracking of a terminal antenna in a satellite communication scenario, and ensures the consistency of the terminal satellite communication performance during the satellite overtop process. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a connection diagram of the electromechanical integrated small planar phased array antenna satellite tracking device and the matching terminal in the embodiment of the application.

[0043] Figure 2 is a structural diagram of the electromechanical integrated small planar phased array antenna satellite tracking device.

[0044] Figure 3 is a flowchart of the satellite tracking method of the electromechanical integrated small planar phased array antenna in the embodiment of the application.

[0045] Figure 4 is a coordinate system diagram used in the embodiment of the application.

[0046] Figure 5 is a flowchart of the joint satellite pointing of beam synthesis and mechanical angle compensation in the embodiment of the application.

[0047] Figure 6 is a flowchart of the joint tracking of beam synthesis and mechanical angle compensation in the embodiment of the application. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0049] An electromechanical integrated small planar phased array antenna satellite tracking method, which realizes satellite pointing and tracking of a small planar phased array antenna in a joint manner of beam synthesis and mechanical angle compensation, comprises 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 array element of the small planar phased array antenna is turned on, and the other array elements are turned off, and the central array element is used for satellite search to obtain the satellite ephemeris information;

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

[0053] S4, according to the beam azimuth and the beam elevation, the small planar phased array antenna is controlled to point to the satellite by using the combined method of beam synthesis and mechanical angle compensation, and the satellite operation is completed;

[0054] S5, during the satellite overhead process, the beam pointing is controlled by using the combined satellite tracking method of beam synthesis and mechanical angle compensation, so as to realize satellite tracking;

[0055] S6, the satellite switching instruction issued by the satellite is received, the beam information of the subsequent satellite is obtained, the small planar phased array antenna array surface is adjusted to the preparation attitude, and the operations of steps S2 to S6 are repeated.

[0056] A kind of electromechanical integration small planar phased array antenna satellite tracking device, including antenna array surface, inertial navigation unit, GNSS positioning and orientation unit, control unit, servo unit;Wherein:

[0057] The antenna array surface realizes the signal transceiving function between antenna and satellite, arranges multiple microstrip antenna arrays, realizes the normal high gain design of antenna and directional beam synthesis by plane group array method;

[0058] The inertial navigation unit is connected with antenna array surface in a way of strapdown, for obtaining the attitude of antenna array surface;

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

[0060] The control unit obtains the beam pointing instruction according to the current antenna array surface pointing obtained by the inertial navigation unit and the GNSS positioning and orientation unit, combines satellite ephemeris information, controls the antenna array surface to complete beam synthesis, and controls the servo unit to rotate the antenna array surface to carry out mechanical angle compensation;

[0061] The servo unit rotates the antenna array surface according to the antenna array surface mechanical angle compensation instruction issued by the control unit, meets the mechanical angle compensation demand of antenna array surface when pointing to satellite and tracking.

[0062] The device needs to be connected with a matched communication terminal in use, and the matched communication terminal is used for completing satellite broadcast signal acquisition, synchronization, and ephemeris information analysis, and delivering the ephemeris information to the control unit.

[0063] As shown in Figure 1 , the communication terminal 101 provides necessary information required for realizing the satellite pointing and tracking function of the planar phased array antenna 102, has satellite communication system information analysis capability, can complete initial acquisition of the satellite broadcast signal received by the planar phased array antenna 102, demodulates and analyzes the broadcast information, obtains the ephemeris information of the satellite, and sends the ephemeris information to the planar phased array antenna 102, to prepare for the next step of completing the satellite pointing and tracking process. It should be understood that the communication terminal 101 is not a necessary device for realizing the satellite pointing and tracking function of the planar phased array antenna 102, and in other optional embodiments, a satellite signal demodulation processing module can be provided at the planar phased array antenna 102 to realize initial acquisition of the satellite broadcast signal and analysis and acquisition of the satellite broadcast ephemeris.

[0064] As shown in Figure 2 , the planar phased array antenna 102 mainly comprises 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 surface 102-1 is used to realize the signal transmission and reception function between the antenna and the satellite. On the antenna array surface, a plurality of microstrip antenna arrays are arranged, and the phase information of each array element sent by the receiving control unit 102-4 is used to form a beam pointing to a specific direction.

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

[0067] The servo unit 102-3 receives the antenna array mechanical angle compensation instructions issued by the control unit 102-4, realizes the rotation of the antenna array 102-1 according to the required angle on the pitch axis and the azimuth axis, and thus meets the requirement of the mechanical angle compensation of the antenna array 102-1 during the satellite pointing and tracking.

[0068] The inertial navigation unit 102-5 is coupled with the antenna array 102-1 to determine the attitude of the antenna array at each moment relative to a topocentric coordinate system, the origin of which is located at the geometric center of the antenna array, and the coordinate axes of which are directed to coincide with the local northeast celestial direction;

[0069] The control unit 102-4 undertakes the data acquisition, calculation processing and instruction generation tasks of the entire planar phased array antenna 102, calculates the orbit of the target satellite by receiving the ephemeris information from the matching communication terminal, 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, calculates the attitude information of the current antenna array by receiving the specific force and angular velocity information from the inertial navigation unit, calculates the beam pointing angle required for the current time to star or track and the angle required for the mechanical compensation of the antenna array according to the star pointing and tracking algorithm stored in the control unit 102-4, controls the antenna array to complete beam synthesis, and controls the servo unit to rotate to realize beam pointing to the desired direction.

[0070] Based on the antenna position and orientation information given 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 cooperating with the corresponding filtering algorithm, combined navigation of multi-source navigation data fusion can be realized 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, a Kalman filter-based algorithm or other online optimal estimation algorithm.

[0071] It should be understood that the apparatus can also include additional blocks not shown and / or the blocks shown can be omitted, the components shown can be implemented in hardware, software or a combination thereof, and the scope of the present application is not limited in this respect.

[0072] As shown in Figure 3 , the electromechanical integrated small planar phased array antenna star tracking method includes the following steps:

[0073] S1, the small planar phased array antenna is powered on, the antenna position information and attitude information are obtained by using the GNSS positioning and orientation unit and the inertial navigation unit, and the antenna fixed coordinate system and the topocentric coordinate system are established, and the antenna array is adjusted to the preparation attitude by the servo mechanism.

[0074] Referring to Figure 4 , in step S1, the topocentric coordinate system is a local northeast celestial coordinate system, denoted by n, and the coordinate axes are OX n Y n Z n , the coordinate system origin is at the geometric center of the antenna array, the X n axis points to the local geographical east direction, the Y n axis points to the local geographical north direction, and the Zn The X axis points to the sky, and is coincident with the X n The Y n The two axes form a right-hand system; the antenna-fixed coordinate system is an antenna-fixed front-left-up coordinate system, denoted as a, and the coordinate axes are OX a The Y a The Z a The coordinate origin is at the geometric center of the antenna array surface, the X a The X axis coincides with the long axis of the antenna array surface, the Y a The Z axis coincides with the short axis of the antenna array surface and points to the left side, and the Z a The X axis points to the sky, and is coincident with the X a The Y a The two axes form a right-hand system. The inertial navigation unit is mounted in a strapdown manner with the antenna array surface, and the coordinate axes thereof coincide with the axes of the antenna-fixed coordinate system, so that the attitude of the antenna-fixed coordinate system relative to the geocentric coordinate system can be solved in real time using the data measured by the inertial navigation unit, and further, the attitude conversion matrix from the n system to the a system is denoted as The baseline of the GNSS positioning and orientation unit coincides with the long axis of the antenna array surface, that is, coincides with the X a axis of the antenna-fixed coordinate system, so that the deflection azimuth angle of the long axis of the antenna in the local horizontal plane can be measured using the GNSS positioning and orientation unit. Further, Figure 4 The geocentric terrestrial coordinate system ECEF is also defined, denoted as e, and the coordinate axes are OX e The Y e The Z e The origin is the center of the Earth, the Z e The X axis coincides with the axis of the Earth, the X e The Y axis is located on the equatorial plane and points to the prime meridian, and the Y e The X axis points to the sky, and is coincident with the X e The Z e The Z axis is perpendicular and forms a right-hand coordinate system.

[0075] The servo unit of the planar phased array antenna includes an elevation axis and an azimuth axis, as shown in Figure 4 The azimuth axis is collinear with the antenna support 401, and the antenna can rotate about the axis to change the azimuth angle of the array surface, and the elevation axis coincides with the short axis of the antenna array surface, and the antenna can rotate about the axis to change the elevation angle of the array surface.

[0076] The prepared attitude in step S1 is the attitude in which the vector from the center of the Earth to the geometric center of the antenna array surface coincides with the OZ a axis of the antenna-fixed coordinate system, so as to ensure that the antenna array surface is in a horizontal state; further, the antenna array surface can be adjusted to the prepared attitude through the following steps:

[0077] Using the GNSS positioning and orientation unit and the GNSS positioning algorithm, the position vector of the antenna in the ECEF system at the initial time can be obtained Further, the longitude λ of the location where the antenna is located can be obtainedA , latitude L A , height H A ; based on the longitude, latitude and height information, a coordinate conversion matrix from the ECEF system e to the station-centered coordinate system n can be obtained is expressed as follows:

[0078]

[0079] The coordinate conversion matrix of the antenna-fixed coordinate system a relative to the station-centered coordinate system n can be obtained in real time by using the data measured by the inertial navigation unit Further, the coordinate conversion matrix from the ECEF system to the antenna-fixed coordinate system is The pointing vector from the earth center to the geometric center of the antenna array plane is In the antenna-fixed coordinate system, it is expressed as:

[0080]

[0081] The azimuth angle Az in the antenna-fixed coordinate system a0 and the elevation angle El a0 can be obtained by the following formula:

[0082]

[0083] To adjust the antenna array plane from the upper power state to the preparation state, the antenna array plane can be first rotated by the azimuth angle Az a0 , and then rotated by the elevation angle El c = min{90° - El a0 , El cmax} degrees, where El cmax is the maximum angle that the antenna servo mechanism can rotate in the elevation axis, without distinguishing between positive and negative. It should be noted that the rotation angle El c has positive and negative, and when the rotation angular velocity vector coincides with the positive direction of the OY a axis, El c is positive, otherwise it is negative.

[0084] In other embodiments, the preparation state can also be the antenna array plane formed by the servo unit rotating through a specific angle in the elevation axis / azimuth axis, and the corresponding angle can be determined by the line-of-sight azimuth of the satellite in the known communication satellite constellation, so that the compensation angle required for mechanical compensation is as small as possible.

[0085] S2, only turn on the central antenna elements of the small planar phased array antenna, and turn off other elements, and use the central elements to search for satellites to obtain the ephemeris information of the satellites.

[0086] In step S2, the central array element is an omnidirectional antenna, and the central array element refers to an antenna array element closest to the geometric center of the small planar phased array antenna. 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 the satellite ephemeris can be completed by the matching communication terminal 101. Further, the ephemeris obtaining process depends on the following steps:

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

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

[0089] The terminal obtains the satellite ephemeris information based on the satellite broadcast information.

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

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

[0092] In step S3, after the planar phased array control unit 102-4 receives the satellite ephemeris information, the current time is taken as the initial time, and the position vector of the satellite in the ECEF system at the initial time can be calculated based on the ephemeris information. Further, the position information of the antenna can be obtained by the GNSS positioning and orientation unit. Specifically, by using the GNSS positioning algorithm, the position vector of the antenna in the ECEF system at the initial time can be obtained by the GNSS positioning and orientation unit. Further, the longitude λ A , the latitude L A , and the height H A of the location where the antenna is located can be obtained. Based on the longitude, latitude, and height information, the coordinate conversion matrix from the ECEF system e to the station-centered coordinate system n in step S1 can be obtained. The coordinate conversion matrix is represented as follows:

[0093]

[0094] The coordinate conversion matrix of the antenna fixed coordinate system a relative to the station-centered coordinate system n can be obtained in real time by using the data measured by the inertial navigation unit. Further, the coordinate conversion matrix from the ECEF system to the antenna fixed coordinate system is Thus, the pointing vector of the satellite in the antenna fixed coordinate system is represented as:

[0095]

[0096] Beam azimuth angle Az a and beam elevation angle El a may be obtained by the following formula:

[0097]

[0098] S4, according to the beam azimuth angle and the beam elevation angle, the small planar phased array antenna is controlled to point to the satellite by means of the combination of beam synthesis and mechanical angle compensation, and the satellite pointing operation is completed.

[0099] In step S4, the planar phased array antenna is controlled to point to the satellite by means of the combination of beam synthesis and mechanical angle compensation, and the purpose is to improve the antenna satellite pointing performance in the low satellite elevation angle scene by means of mechanical rotation of the array surface of the antenna and cooperation of the electric scanning beam synthesis, as shown in the following formula: Figure 5 The specific steps include:

[0100] S41, the relationship between the beam elevation angle El a and the pre-defined angle compensation threshold El 0t is considered to determine whether mechanical angle compensation is needed;

[0101] S42, if El a < El 0t , mechanical angle compensation is performed, and the satellite pointing operation is completed by means of the combination of mechanical angle compensation and beam synthesis;

[0102] S43, if El a ≥ El 0t , mechanical angle compensation is not needed, and the small planar phased array antenna directly adopts the beam synthesis mode to control the beam to point to the satellite, and the satellite pointing operation is completed.

[0103] In step S41, the angle compensation threshold El 0t is determined to determine whether mechanical angle compensation is needed during satellite pointing, and the threshold value should be determined based on the beam gain curve of the phased array antenna. Alternatively, it is assumed that the beam gain of the phased array antenna is significantly reduced when the elevation angle is less than 15°, and the minimum working elevation angle of the antenna required by the task is El min = 10°, in order to ensure the satellite pointing gain of the antenna at 10° elevation angle, El 0t = 15° should be set at this time.

[0104] In step S42, the combination of mechanical angle compensation and beam synthesis for satellite pointing includes the following specific steps:

[0105] S421, the small planar phased array antenna obtains the angle required for rotating the antenna array surface based on the pre-set satellite pointing mechanical angle compensation mode, and rotates the antenna array surface to the direction according to the angle.

[0106] S422, re-computing the desired beam azimuth angle Az according to the way of step S3 a and the beam elevation angle El a ;

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

[0108] Optionally, the following way is provided to calculate the angle of the antenna array plane required to be rotated in step S421:

[0109] When the antenna is in the ready posture, first rotate Az a angle around the azimuth axis of the servo unit, and then rotate min{El a -El 0t , El a} angle around the elevation axis in the direction of increasing the beam elevation angle El cmax , where El c is the angle that the servo mechanism elevation axis has turned when the antenna array plane is adjusted from the power-on posture to the ready posture in step S1, and El c is the maximum angle that the antenna servo mechanism elevation axis can turn. cmax

[0110] S5, during the satellite overhead process, the beam pointing is controlled by using the combined satellite tracking way of beam synthesis and mechanical angle compensation to realize satellite tracking.

[0111] In step S5, during the satellite overhead process, the beam pointing of the planar phased array antenna is controlled by using the combined satellite tracking way of beam synthesis and mechanical angle compensation to realize satellite tracking, as shown in Figure 6 , which 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, the satellite's topocentric coordinate system elevation angle El n (t) is obtained;

[0113] S52, during the satellite overhead process, the small planar phased array antenna preferentially uses the beam synthesis way to control the beam pointing for satellite tracking, and at each time t, the satellite's beam elevation angle El a (t) is calculated;

[0114] S53, at each time t, the beam elevation angle El a (t) is considered together with the angle compensation threshold El 0t ​​relationship between El

[0115] S54, at each time t, considering the satellite's topocentric coordinate system elevation angle El n (t) and the tracking compensation cutoff threshold El nt relationship, when El n (t) < El nt , stop mechanical tracking compensation.

[0116] Further, the satellite's elevation angle El n (t) in step S51 in the topocentric coordinate system can be calculated as follows:

[0117] The satellite's position vector in the ECEF system at time t is calculated using satellite ephemeris information

[0118] The longitude λ A , latitude L A , and height H A of the antenna's location at time t are obtained using the GNSS positioning and orientation unit, and the coordinate conversion matrix from the ECEF system to the topocentric coordinate system is obtained based on the longitude, latitude, and height information

[0119] The satellite's position vector in the topocentric coordinate system can be represented as

[0120] The satellite's elevation angle in the topocentric coordinate system can be obtained as

[0121] In step S52, the method for calculating the satellite's beam elevation angle El a (t) at each time t is the same as step S3.

[0122] In step S53, the method for determining whether to use mechanical angle compensation to achieve satellite tracking is as follows:

[0123] S531, if El a (t) < El 0t , based on the preset tracking mechanical angle compensation scheme, rotate the antenna array surface orientation to perform mechanical angle compensation to ensure that El a (t) is not less than El 0t ;

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

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

[0126] Considering that time is divided into a series of time slots with equal length, the mechanical angle compensation of the antenna array is controlled in a time slot as the minimum control unit; in a minimum control unit, if El a (t) < El 0t , the azimuth axis angle of the antenna servo unit is kept unchanged, the elevation axis is adjusted to make the antenna array rotate 2° around the servo unit elevation axis in the direction of increasing El a (t), and the adjusted El a (t) is calculated; if El a (t) > 3El 0t , the antenna array orientation is kept unchanged in the next control unit; otherwise, the current Az a (t) is calculated in the next control unit by using the same method as in step S3, and the antenna array is made to rotate 2° around the servo unit azimuth axis in the direction of decreasing Az a (t); the elevation axis is continuously adjusted to make the antenna array rotate 2° in the direction of increasing El a (t), until the condition El a (t) > 3El 0t is met, or the condition of the tracking compensation cutoff threshold in step S54 is met, i.e., El n (t) < El nt .

[0127] In step S54, the satellite station heart coordinate system elevation angle El n (t) at each time t is calculated according to the method in step S51; the tracking compensation cutoff threshold El nt is given, and the specific value is given by the task requirement, to ensure that the gain of the beam meets the task requirement in the range where the satellite ground elevation angle is not less than El nt ; further, by setting the value of El nt , the trade-off between the antenna working performance at low satellite elevation angle and the satellite switching efficiency can also be realized. Specifically, when the value of El nt is small, the gain performance of the antenna beam at a lower satellite ground elevation angle can be ensured through the mechanical angle compensation of the antenna array, but the elevation axis rotation angle of the array for realizing the mechanical angle compensation will increase, and the time required for the antenna to adjust to the preparation attitude after receiving the satellite switching instruction will also increase, which means that the beam performance at a low satellite ground elevation angle is ensured at the expense of the antenna switching efficiency; on the contrary, when the value of El nt is large, the antenna switching efficiency is improved at the expense of the beam performance at a low satellite ground elevation angle.

[0128] S6, receiving the cut star instruction issued by the satellite, obtaining the beam information of the subsequent satellite, adjusting the small planar phased array antenna array surface to the preparation posture, and repeating the operations of S2 to S6.

[0129] In summary, the application realizes the improvement of the antenna pointing and tracking performance in the low satellite elevation angle scenario by adjusting the antenna array surface orientation to mechanically compensate the beam, and guarantees the consistency of the terminal communication performance during the satellite overtop process. Compared with the pure mechanical servo pointing and tracking, the application can realize the rapid beam pointing adjustment. Compared with the pure electric scanning pointing and tracking, the application can improve the beam gain in the low satellite elevation angle scenario.

[0130] It should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. 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 and uses the GNSS positioning and orientation unit and the inertial navigation unit to obtain the antenna position and attitude information. The antenna fixed coordinate system and the station center coordinate system are established, and the servo mechanism is used to adjust the antenna array surface to the ready attitude. S2: Only the central element of the small planar phased array antenna is turned on, and the other elements are turned off. The central element is used to search for satellites and 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 of the desired beam pointing and beam elevation ; S4, according to the beam azimuth and beam elevation , 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, completing the satellite pointing operation; the specific method is: S41, considering beam elevation and a pre-given angle compensation threshold To determine whether mechanical angle compensation is required; S42, if , then mechanical angle compensation is performed, and the satellite alignment operation is completed by combining mechanical angle compensation and beamforming; specifically: S421, the small planar phased array antenna obtains a required rotation angle of the antenna array face based on a preset mechanical angle compensation mode for the satellite, and rotates the antenna array face direction accordingly; S422, recalculate the desired beam azimuth and beam elevation ; S423, using beam synthesis to control the beam pointing to the new beam azimuth angle and beam elevation ; S43, if , there is no need for mechanical angle compensation, and the small planar phased array antenna directly uses beam synthesis to control the beam pointing to the satellite to complete the satellite operation; S5: During the satellite's overhead pass, the beam pointing is controlled by combining beam synthesis and mechanical angle compensation to achieve satellite tracking. The specific method is as follows: 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 elevation angle of the satellite's station center coordinate system ; 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 at each moment t ; S53, at each moment t, consider the beam elevation angle and angle compensation threshold The relationship between the two determines whether to use pure beam synthesis or mechanical angle compensation to achieve satellite tracking: like , then the antenna array direction is rotated based on the preset tracking mechanical angle compensation scheme to perform mechanical angle compensation to ensure Not less than ; like , then keep the antenna array still and use beam synthesis to control the beam pointing to achieve satellite tracking; S54, at each moment t, consider the elevation angle of the satellite's station center coordinate system Tracking compensation cutoff threshold relationship, when When , mechanical tracking compensation stops.

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 position 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 satellite ephemeris information by parsing received satellite broadcast information and sends the ephemeris information to the small planar phased array antenna.

4. A mechatronic small-scale planar phased array antenna star tracking device, characterized in that: include: The antenna array plane realizes the signal transmission and reception 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 on the antenna array to obtain the antenna array's attitude; GNSS positioning and orientation unit, used to determine the position and heading angle of the antenna array; A control unit, which obtains a beam pointing instruction based on the current antenna array face pointing obtained by the inertial navigation unit and the GNSS positioning and orientation unit and in combination with satellite ephemeris information; controls the antenna array face to complete beam synthesis according to the method of any one of claims 1 to 3, and controls the servo unit to perform mechanical angle compensation of the antenna array face; The servo unit rotates the antenna array according to the mechanical angle compensation instruction of the antenna array issued by the control unit, thereby compensating the mechanical angle of the antenna array during satellite tracking.

5. The mechatronic small-scale planar phased array antenna star tracking device according to claim 4, 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.

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