Method for tracking inclined geostationary satellite through non-fixed station antenna

Abstract

The invention discloses a method for tracking an inclined geostationary satellite by using a non-fixed station antenna, which belongs to the field of electronic information and comprises the following steps of: selecting a signal tracking receiver to search and calibrate errors, and tracking by combining an angle error correction value and ephemeris data to guide; in order to improve the reliability of the system and to consider both the tracking signal quality and the effective tracking time, a series of angle re-correction strategies are adopted. Compared with a traditional ephemeris position preset tracking mode, a signal closed-loop search tracking process is adopted, so that the satellite pointing error of an antenna can be effectively reduced, the loss of a satellite signal-to-noise ratio is reduced, and the antenna communication and service transmission effects are improved; secondly, compared with a traditional stationary orbit satellite stepping tracking mode, follow-up is carried out according to the theoretical satellite position in the whole searching and tracking process, the antenna does not lose the effective tracking time due to frequent re-searching, and the effective time of antenna communication and service transmission is prolonged;

Description

Technical Field

[0001] The field involved in the design of the present invention is the field of electronic information. It can be used for non-fixed station antennas to track inclined geosynchronous orbit satellites. A new method for non-fixed station antennas to track inclined geosynchronous satellites is proposed to address the problems of poor pointing accuracy and poor signal-to-noise ratio of received signals when non-fixed station antennas use ephemeris position preset methods to track inclined geosynchronous satellites. Background Art

[0002] Since non-fixed station antennas are not fixed to the ground through a foundation, the position of their antenna bases can be moved, so the attitude, position and direction of each operation may change. This makes it impossible to accurately calibrate the attitude, position and direction of such antennas when building the station. They can only rely on sensors to determine the position, which in turn affects the pointing accuracy of the antenna.

[0003] When traditional non-fixed station antennas track geostationary orbit satellites, they use signal receiving and tracking machines to perform step tracking. The signal tracking receiver can provide real-time feedback on the signal-to-noise ratio of the tracking satellite. During the step tracking process, the antenna needs to go through coarse search, azimuth and elevation main-lobe and side-lobe identification search, etc. During each search, the antenna first points to the satellite position and searches in a single direction. If the signal-to-noise ratio decreases, the search in the current direction will no longer be performed and a reverse search will be performed. During the search process, if the signal-to-noise ratio decreases or the search boundary is reached, the search ends.

[0004] Disadvantages of current methods:

[0005] 1) When the antenna uses the pre-set ephemeris position to track the satellite, the pointing error is the error between the antenna pointing position and the actual satellite position. The pointing error is composed of the antenna pointing position and the actual satellite position, that is, △ 指星误差 =△ 指向误差 +△ 星历误差 (The ephemeris error depends on the source of the ephemeris data and will not be discussed here); the large pointing error of the non-fixed station antenna will directly cause the loss of satellite signal-to-noise ratio, and will increase with the increase of antenna aperture and signal frequency;

[0006] 2) When tracking mobile satellites such as tilted geosynchronous satellites, if the step tracking method for geostationary orbit satellites is used, the movement of the satellite will cause signal degradation or loss of lock, causing the antenna to frequently enter a re-search state, resulting in a large loss of time for effective satellite tracking. This time loss will increase with the increase of the orbital inclination of the tilted geosynchronous satellite. Summary of the invention

[0007] The purpose of the present invention is to use a signal tracking receiver to search for calibration errors and combine the angle error correction value with the ephemeris data to guide tracking in order to solve the problem of loss of satellite signal-to-noise ratio caused by the ephemeris position preset method and the problem of loss of satellite alignment time caused by the step tracking method. In order to improve the reliability of the system and to balance the tracking signal quality and effective tracking time, a series of angle re-correction strategies are adopted.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A method for tracking an inclined geosynchronous satellite using a non-fixed station antenna, comprising the following steps:

[0010] Step 1: The antenna obtains the station attitude angle and target satellite ephemeris;

[0011] Step 2, obtaining the real-time pointing position of the satellite through the ephemeris pointing algorithm, and presetting the antenna to the real-time pointing position of the satellite;

[0012] Step 3, setting the real-time satellite pointing position in step 2 as the dynamic origin A, and making the antenna search in the preset search area of ​​azimuth and elevation. If it enters the main beam range, record the deviation A from the real-time satellite pointing position;

[0013] Step 4, superimposing the real-time satellite pointing position in step 2 and the deviation recorded in step 3 to obtain the dynamic origin B, so that the antenna searches again within the preset width of the azimuth or pitch axis to obtain the position of the maximum signal strength, and records the deviation B from the real-time satellite pointing position;

[0014] Step 5, superimpose the real-time satellite pointing position in step 2 and the deviation B recorded in step 4 to obtain the dynamic origin C, so that the antenna can perform step tracking on the azimuth axis or the pitch axis to find the optimal position, and record the deviation C from the real-time satellite pointing position;

[0015] Step 6, superimpose the real-time satellite pointing position in step 2 with the deviation C recorded in step 5 to obtain the dynamic tracking pointing position.

[0016] Furthermore, in step 6, if the signal leaves the main beam range, proceed to step 3; if the signal fluctuation exceeds the preset range, proceed to step 5; if it is identified that the target satellite enters the latitude extreme, proceed to step 3; if the time to enter stable tracking exceeds the preset time, proceed to step 3.

[0017] Furthermore, in step 3 to step 6, the antenna calculates a dynamic satellite pointing theoretical position through an ephemeris pointing algorithm, and its search and tracking ranges are dynamic ranges based on the dynamic position.

[0018] Furthermore, in steps 4 to 6, the origin of the antenna's search and tracking range is formed by superposition of the satellite pointing position and the deviation of the previous step.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1) Compared with the traditional tracking method of presetting the ephemeris position, the signal closed-loop search and tracking process can effectively reduce the antenna's pointing error, reduce the loss of satellite signal-to-noise ratio, and improve the antenna communication and business transmission effect;

[0021] 2) Compared with the traditional geostationary orbit satellite step tracking method, the antenna follows the theoretical satellite position throughout the search and tracking process. The antenna will not lose effective tracking time due to frequent re-searching, thereby improving the effective time of antenna communication and business transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the tracking method of the present invention. DETAILED DESCRIPTION

[0023] The following is a complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The specific steps of the present invention are as follows:

[0025] 1) The antenna enters the tracking initialization phase: obtains the station attitude angle and target satellite ephemeris, and enters the initial capture phase;

[0026] 2) The antenna enters the initial acquisition phase: the real-time theoretical angle of the satellite is obtained through the ephemeris pointing algorithm, and the antenna angle is preset to this position, and then the coarse search phase is entered;

[0027] 3) The antenna enters the coarse search stage, takes the calculated real-time satellite pointing position as the dynamic origin, and performs a "return" search in the preset search area of ​​azimuth and elevation. If the signal is locked, it enters the main beam range, records the deviation from the theoretical position, and enters the fine search stage (if the coarse search times out and is not locked, it switches to pure theoretical satellite real-time pointing until it is locked again and then enters the fine search stage);

[0028] 4) The antenna enters the fine search stage, and the calculated real-time satellite pointing position is superimposed with the recorded rough search deviation to obtain the dynamic origin. A "one" traversal fine search is performed within the preset width of the azimuth or pitch axis to obtain the position with the maximum signal strength, and the deviation from the theoretical position is recorded, and the tracking fine-tuning stage is entered;

[0029] 5) The antenna enters the tracking fine-tuning stage, superimposes the calculated real-time satellite pointing position with the recorded precise search deviation to obtain the dynamic origin, performs step tracking on the azimuth axis or pitch axis, finds the optimal position, and records the deviation from the theoretical position, and then enters the stable tracking stage;

[0030] 6) The antenna enters the stable tracking stage, and the calculated real-time satellite pointing position is superimposed with the recorded tracking fine-tuning deviation to obtain the dynamic tracking pointing position (① If the signal is lost, switch to coarse search; ② If the signal fluctuation exceeds the preset range, switch to tracking fine-tuning; ③ If the target satellite is identified to enter the latitude extreme, switch to coarse search; ④ If the time to enter stable tracking exceeds the preset time, switch to coarse search).

[0031] The following is a more specific embodiment:

[0032] Reference Figure 1 , the specific process is as follows:

[0033] 1) When the tracking antenna is powered on or receives the tracking command and ephemeris file after being powered on, the antenna enters the tracking initialization phase: the station latitude and longitude, heading, attitude angle, ephemeris file of the target satellite and the signal strength data after real-time demodulation by the tracking receiver are obtained through the interface protocol, and then the initial capture phase is entered;

[0034] 2) The antenna enters the initial acquisition phase: the real-time theoretical angle of the satellite is obtained through the ephemeris pointing algorithm, and the antenna angle is preset to the theoretical position, and then the coarse search phase is entered;

[0035] 3) The antenna enters the coarse search stage, takes the calculated real-time satellite pointing position as the dynamic origin, and performs a "return" search in the preset search area in azimuth and elevation. During the search process, the signal strength of the tracking receiver is monitored in real time. If it is higher than the preset signal threshold, the signal is locked, that is, it enters the main beam range, and the deviation from the theoretical position is recorded, and the fine search stage is entered (if the coarse search times out and is not locked, it switches to pure theoretical satellite real-time pointing until it is re-locked and then enters the fine search stage);

[0036] 4) The antenna enters the fine search stage, and the calculated real-time satellite pointing position is superimposed with the recorded rough search deviation to obtain the dynamic origin. A "one-line" traversal fine search is performed within the preset width of the azimuth or pitch axis. By comparing the collected signal strengths, the position with the maximum signal strength is found, and the antenna returns to that position. The deviation from the theoretical position is recorded, and the tracking fine-tuning stage is entered;

[0037] 5) The antenna enters the tracking fine-tuning stage, superimposes the calculated real-time satellite pointing position with the recorded precise search deviation to obtain the dynamic origin, performs step tracking on the azimuth axis or pitch axis, finds the optimal position, and records the deviation from the theoretical position, and then enters the stable tracking stage;

[0038] 6) The antenna enters the stable tracking stage, and the calculated real-time satellite pointing position is superimposed with the recorded tracking fine-tuning deviation to obtain the dynamic tracking pointing position (① If the signal is lost, switch to coarse search; ② If the signal fluctuation exceeds the preset range, switch to tracking fine-tuning; ③ If the target satellite is identified to enter the latitude extreme, switch to coarse search; ④ If the stable tracking time exceeds the preset time, switch to coarse search).

Claims

1. A method for tracking an inclined geosynchronous satellite using a non-fixed station antenna, characterized in that: The specific steps are as follows: Step 1: The antenna obtains the station attitude angle and target satellite ephemeris; Step 2, obtaining the real-time pointing position of the satellite through the ephemeris pointing algorithm, and presetting the antenna to the real-time pointing position of the satellite; Step 3, setting the real-time satellite pointing position in step 2 as the dynamic origin A, and making the antenna search in the preset search area of ​​azimuth and elevation. If it enters the main beam range, record the deviation A from the real-time satellite pointing position; Step 4, superimposing the real-time satellite pointing position in step 2 and the deviation recorded in step 3 to obtain the dynamic origin B, so that the antenna searches again within the preset width of the azimuth or pitch axis to obtain the position of the maximum signal strength, and records the deviation B from the real-time satellite pointing position; Step 5, superimpose the real-time satellite pointing position in step 2 and the deviation B recorded in step 4 to obtain the dynamic origin C, so that the antenna can perform step tracking on the azimuth axis or the pitch axis to find the optimal position, and record the deviation C from the real-time satellite pointing position; Step 6, superimpose the real-time satellite pointing position in step 2 with the deviation C recorded in step 5 to obtain the dynamic tracking pointing position.

2. A method for tracking an inclined geosynchronous satellite using a non-fixed station antenna according to claim 1, characterized in that: In step 6, if the signal is out of the main beam range, proceed to step 3; If the signal fluctuation exceeds the preset range, go to step 5; if it is identified that the target satellite enters the latitude extreme, go to step 3; If the time to enter stable tracking exceeds the preset time, go to step 3.

3. The method for tracking an inclined geosynchronous satellite using a non-fixed station antenna according to claim 1, characterized in that: In step 3 to step 6, the antenna calculates the dynamic satellite pointing theoretical position through the ephemeris pointing algorithm, and its search and tracking ranges are dynamic ranges based on the dynamic position.

4. The method for tracking an inclined geosynchronous satellite using a non-fixed station antenna according to claim 1, characterized in that: In steps 4 to 6, the origin of the antenna's search and tracking range is the superposition of the satellite pointing position and the deviation of the previous step.

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