A system architecture supporting over-the-top tracking of large antennas

Abstract

The present invention discloses a system architecture for supporting over-the-top tracking of large antennas, including a large-aperture reflector antenna, which has a reflector surface, and a feed source is also provided at the focal point of the reflector surface of the large-aperture reflector antenna; it also includes a feed source mobile platform, and the feed source mobile platform is composed of a motion platform and a feed source installed on the motion platform; on the basis of a two-dimensional turntable, a two-dimensional mobile platform for the feed source is added. When the antenna has a need for over-the-top tracking, the position where the phase center of the feed source deviates from the focal point of the reflector surface is changed by controlling the movement of the feed source mobile platform to support the tracking of the system antenna. Since the feed source is light in weight, the platform for supporting the two-dimensional movement of the feed source is light in mass, the difficulty of servo drive control is low, and the system reliability is high. Especially for large-aperture antennas, this design of the scheme can significantly improve the over-the-top tracking characteristics of the antenna while the impact on the system can be ignored.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite communication, and particularly relates to a system architecture supporting over-the-top tracking of a large antenna. Background Art

[0002] When a reflector antenna for satellite communication uses azimuth and elevation two-dimensional turntables to track a communication satellite, there is an over-the-top tracking problem. Currently, there are two solutions. One is to solve the over-the-top tracking problem based on a software control strategy, that is, program tracking. The other is that the antenna pedestal turntable can support over-the-top tracking of the antenna. In this case, there are currently two solutions. One is a three-axis system, and the other is an XY carriage system. The former adds a third axis on the basis of the two-dimensional turntable. The addition of the third axis significantly increases the pedestal mass, increases the control difficulty of the transmission system, and reduces the system reliability at the same time. Summary of the Invention

[0003] The purpose of the present invention is to provide a system architecture supporting over-the-top tracking of a large antenna to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A system architecture supporting over-the-top tracking of a large antenna includes a large-aperture reflector antenna, which has a reflecting surface, and a feed is also provided at the focal point of the transmitting surface of the large-aperture reflector antenna; it also includes a feed moving platform, and the feed moving platform is composed of a moving platform and a feed installed on the moving platform; the moving platform moves on a plane corresponding to the feed focal point, and the feed moving platform is arranged on a two-dimensional turntable.

[0005] As a preferred technical solution in the present invention, it also includes a communication satellite, and the two-dimensional turntable rotates to direct the beam of the feed moving platform to the angle where the communication satellite is located.

[0006] As a preferred technical solution in the present invention, the antenna beam elevation pointing angle E B and the relationship between the antenna rotation speed is as follows:

[0007] where E B is the antenna beam elevation pointing angle; A is the maximum speed of the azimuth turntable; h is the distance between the target satellite and the ground station; R E is the radius of the earth; μ is the acceleration of gravity of the earth.

[0008] As a preferred technical solution in the present invention, the feed moving platform is used for quickly switching the beam pointing of the large-aperture reflector antenna to complete scanning of a large spatial angle within a short time.

[0009] As a preferred technical solution in the present invention, the steps for the azimuth and elevation turntables of the feed moving platform to specifically track the satellite over the top are as follows:

[0010] Step 1: Based on the geodetic coordinate system, calculate the positional relationship between the ground antenna and the communication satellite antenna according to the satellite orbit parameters, and obtain the relative angle θ between the direction at the top of the antenna and the current satellite. s ;

[0011] Step 2: Drive the azimuth turntable and the elevation turntable to make the maximum value of the antenna beam point to the target communication satellite and lock the satellite signal to enter the automatic satellite tracking mode.

[0012] Step 3: When the antenna beam tracks within the set preset over-the-top tracking angle, start driving the feed moving platform to change the direction of the antenna beam, and the antenna enters the over-the-top tracking mode.

[0013] Step 4: After the antenna enters the over-the-top tracking mode, the speed of the azimuth turntable of the antenna turntable will be limited to below the maximum rotational speed supported by the azimuth turntable. If the rotational speed of the azimuth turntable reaches the maximum designed rotational speed, the azimuth rotational speed remains unchanged at the maximum speed.

[0014] Step 5: When the target satellite passes over the top of the antenna and reaches the other side, and is about to pass through the preset over-the-top tracking angle, at this time, the azimuth turntable rotates 180°. The feed moving platform synchronously controls the feed to return to the initial focal position, and the speed of the azimuth turntable starts to decrease as the tracking target satellite points to the elevation angle deviating from the direction at the top of the antenna and becomes larger.

[0015] Step 6: After the tracking angle pointing to the target satellite exceeds the over-the-top tracking preset angle, the antenna enters the automatic satellite tracking mode.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] Based on the two-dimensional turntable, a two-dimensional feed moving platform is added. When the antenna has a need for over-the-top tracking, by changing the position of the feed deviating from the focal point of the reflector, it supports the antenna tracking of the system. Since the feed is light in weight, the platform supporting the two-dimensional movement of the feed is light in mass, simple in structure, low in servo drive control difficulty, and high in system reliability. Especially in large-aperture antennas, this system solution design can significantly improve the over-the-top tracking characteristics of the antenna while the impact on the system can be ignored. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the reflector feed movement of the present invention;

[0019] Figure 2 It is a schematic diagram of the change in the pointing of the reflector feed moving beam of the present invention;

[0020] Figure 3 These are block diagrams of two typical system architectures in the present invention. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] Please refer to Figures 1 to 3 , the present invention provides a technical solution: a system architecture supporting large antenna over-the-top tracking, including a large-aperture reflector antenna, which has a reflector, and a feed is also provided at the focus of the transmitting surface of the large-aperture reflector antenna; it also includes a feed moving platform, which is composed of a moving platform and a feed installed on the moving platform; the moving platform moves on the plane corresponding to the focus of the feed, and this movement will cause the radiation beam of the reflector antenna to deflect. When the satellite needs over-the-top tracking, it can deviate from the feed in advance, so that the antenna beam deviates from the azimuth turntable axis. At this time, synchronously adjusting the azimuth angle and the distance of the feed deviating from the focus can achieve over-the-top tracking of the satellite communication antenna, and the feed moving platform is arranged on a two-dimensional turntable.

[0023] In this embodiment, it also includes a communication satellite, and the two-dimensional turntable points the beam of the feed moving platform to the angle where the communication satellite is located by rotation.

[0024] In this embodiment, the elevation pointing angle E of the antenna beam B and the relationship between the antenna rotation speed are as follows:

[0025] where E B is the elevation pointing angle of the antenna beam; A is the maximum speed of the azimuth turntable; h is the distance between the target satellite and the ground station; R E is the radius of the earth; μ is the acceleration of gravity of the earth. It can be seen from the formula that as the beam pointing angle increases and approaches 90°, the azimuth rotation speed of the earth station increases sharply. When the beam pointing angle is 90°, the speed of the azimuth turntable approaches infinity; let the maximum azimuth rotation speed that the turntable can support be A max , then the maximum elevation angle that the azimuth elevation turntable of the earth station can point to and track is E Bmax ; that is, when the satellite enters the range of the elevation angle E Bmax ~90° of the azimuth-elevation turntable, the azimuth turntable speed required to track the target satellite will be greater than A max , when E BWhen approaching 90°, the azimuth turntable speed will approach infinity; since the maximum value of the azimuth turntable speed is a finite value, when the satellite enters the range of E Bmax ~90°, due to the limitation of the turntable azimuth speed, the antenna beam cannot point to the satellite, resulting in satellite pointing and tracking failure.

[0026] In this embodiment, the feed moving platform is used for the rapid switching of the pointing of the large-aperture reflector antenna beam, and completes the scanning of a large spatial angle within a short time. This characteristic can support the system to quickly and accurately track the satellite to ensure the communication quality. The main solution of this scheme is to add a feed moving platform, and change the beam pointing by the moving distance of the feed, assisting the azimuth-elevation turntable to achieve the over-the-top tracking of the target satellite. According to the characteristics of the reflector antenna, when the feed is at the focus of the reflector antenna, the beam of the reflector antenna points to the normal direction of the aperture plane, that is, the Z-axis direction. When the feed moves off-focus in the focal plane XOY plane, the beam of the antenna will move in the opposite direction of the feed movement, forming a certain angle θ with the Z-axis, θ = 90° - E B , assuming that the diameter of the reflector antenna aperture is D, the focal ratio of the antenna is fd, and the moving distance of the antenna is Ds, then the beam pointing angle of the antenna is as follows:

[0027]

[0028] Among them, B df is the beam pointing correction data related to the focal ratio of the reflector and the taper of the feed illuminating the reflector.

[0029] In this embodiment, the specific steps for the azimuth and elevation turntables of the feed moving platform to achieve over-the-top tracking of the satellite are as follows:

[0030] Step 1: Based on the geodetic coordinate system, calculate the position relationship between the ground antenna and the communication satellite antenna according to the satellite orbit parameters, and obtain the relative angle θ between the top direction of the antenna and the current satellite s ;

[0031] Step 2: Drive the azimuth turntable and elevation turntable to make the maximum value of the antenna beam point to the target communication satellite and lock the satellite signal to enter the automatic satellite tracking mode;

[0032] Step 3: When the antenna beam tracks within the set preset over-the-top tracking angle, start driving the feed moving platform to change the pointing of the antenna beam, and the antenna enters the over-the-top tracking mode;

[0033] Step 4: After the antenna enters the over-the-top tracking mode, the azimuth turntable speed of the antenna turntable will be limited to below the maximum rotation speed supported by the azimuth turntable. If the azimuth turntable speed reaches the maximum design speed, the azimuth speed remains unchanged at the maximum speed;

[0034] Step 5: When the target satellite passes over the top of the antenna and reaches the other side, about to pass through the preset over-the-top tracking angle, at this time, the azimuth turntable rotates 180°, and the feed moving platform synchronously controls the feed to return to the initial focus position. The speed of the azimuth turntable begins to decrease as the tracking target satellite points to the pitch angle deviating from the top of the antenna and increases;

[0035] Step 6: After the tracking angle pointing to the target satellite exceeds the over-the-top tracking preset angle, the antenna enters the automatic satellite tracking mode.

[0036] Refer to Figure 2 , which shows the angle change of the antenna beam pointing when the feed is at the focus of the reflector and deviates from the focus of the reflector. Among them, the beam pointing to 0° is the beam formed when the feed is at the focus of the reflector.

[0037] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A system architecture for supporting over-the-top tracking of large antennas, including a large-aperture reflector antenna, characterized in that: The large-aperture reflector antenna has a reflector, and a feed is also provided at the focus of the reflector of the large-aperture reflector antenna; it also includes a feed moving platform, and the feed moving platform is composed of a moving platform and a feed installed on the moving platform; when the moving platform moves, the phase center of the feed can move on the plane corresponding to the focus of the reflector, and the feed moving platform is arranged on a two-dimensional turntable; The feed moving platform is used to change the position of the feed of the large-aperture reflector antenna, further causing the antenna beam pointing to move deviating from the axial direction of the reflector, and combining with the movement of the antenna two-dimensional turntable to realize the real-time tracking of the overhead communication satellite.

2. The system architecture for supporting over-the-top tracking of large antennas according to claim 1, wherein: It also includes a communication satellite, and the two-dimensional turntable rotates to direct the beam of the reflector antenna to the angle where the communication satellite is located.

3. The system architecture for supporting over-the-top tracking of large antennas according to claim 2, characterized in that: The pitch pointing angle E of the antenna beam B and the relationship with the antenna rotation speed is as follows: Where E B is the pitch pointing angle of the antenna beam; A is the maximum speed of the azimuth turntable; h is the distance between the target satellite and the ground station; R E is the radius of the earth; μ is the acceleration of gravity of the earth.

4. A system architecture for supporting over-the-top tracking of large antennas according to claim 1, characterized in that: The specific steps for the azimuth and elevation turntables of the feed moving platform to track the satellite overhead are as follows: Step 1: Based on the geodetic coordinate system, calculate the positional relationship between the ground antenna and the communication satellite antenna according to the satellite orbit parameters, and obtain the relative angle θ between the top direction of the antenna and the current satellite s ; Step 2: Drive the azimuth turntable and the elevation turntable to make the maximum value of the antenna beam point to the target communication satellite and lock the satellite signal to enter the automatic satellite tracking mode; Step 3: When the antenna beam tracks within the set preset overhead tracking angle, start to drive the feed moving platform to change the pointing of the antenna beam, and the antenna enters the overhead tracking mode; Step 4: After the antenna enters the overhead tracking mode, the speed of the azimuth turntable of the antenna turntable will be limited to below the maximum rotation speed supported by the azimuth turntable. If the rotation speed of the azimuth turntable reaches the maximum design rotation speed, the azimuth rotation speed remains unchanged at the maximum speed; Step 5: After the target satellite passes over the top of the antenna and reaches the other side, about to pass through the preset overhead tracking angle, at this time the azimuth turntable rotates 180°, and the feed moving platform synchronously controls the feed to return to the initial focus position, and the speed of the azimuth turntable begins to decrease as the tracking target satellite points to the elevation angle deviating from the top direction of the antenna and becomes larger; Step 6: After the tracking angle pointing to the target satellite exceeds the overhead tracking preset angle, the antenna enters the automatic satellite tracking mode.

Images