Method for measuring and calibrating pointing deviation of multi-beam antenna in satellite antenna coordinate system

Abstract

The application relates to a kind of measurement and calibration method of multi-beam antenna pointing deviation under satellite antenna coordinate system, belong to satellite communication technical field.The application takes the measurement and calibration of mobile communication satellite phased array multi-beam antenna pointing deviation as input, establishes the relationship model of pointing measurement, uses the relationship model between ground calibration station and satellite posture, adjusts the beam pointing of mobile communication satellite phased array multi-beam antenna by adjusting satellite posture or phased array antenna beam forming parameter, realizes the calibration of multi-beam antenna pointing deviation.

Description

Technical Field

[0001] This invention relates to a method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system. This method is applicable to the measurement and calibration of the pointing of multi-beam satellite antennas in satellite mobile communication systems and belongs to the field of satellite communication technology. Background Technology

[0002] Geostationary orbit mobile communication satellites employ large, deployable multi-beam antennas to support a large number of mobile users with handheld devices. Due to factors such as the gravitational pull of the sun and moon, the inhomogeneity of the Earth's gravitational field, and solar radiation pressure, large deployable multi-beam antennas exhibit greater pointing deviations than traditional communication satellite antennas. To ensure the pointing accuracy of the mobile communication satellite's multi-beam antenna, it is necessary to further improve the beam pointing accuracy using integrated satellite-ground beam calibration, in addition to the satellite's three-axis attitude dynamic offset method, to meet the system's operational requirements.

[0003] Beam calibration can be divided into downlink calibration and uplink calibration. Downlink beam calibration typically involves a gateway station or satellite transmitting a calibration signal, with a ground-based beam calibration receiving station distinguishing the energy of different beam calibration signals to obtain the antenna pointing deviation. Uplink beam calibration, on the other hand, involves a ground-based beam calibration station transmitting a calibration signal, with the satellite or gateway station estimating the energy and comparing the field strength to obtain the antenna pointing deviation. In this system, the ground calibration station functions as a radio frequency sensor.

[0004] Both downlink and uplink calibrations require establishing a measurement relationship between the measured data and the antenna pointing deviation, measuring the azimuth, elevation, and yaw deviations of the satellite antenna. Because the measurement error for yaw values ​​based on radio frequency sensors is much greater than with other sensors, it affects the calibration accuracy of the multi-beam antenna pointing deviation. Summary of the Invention

[0005] To address the antenna pointing calibration problem of geostationary mobile communication satellites employing large deployable antennas, this invention proposes a method for measuring and calibrating the pointing deviation of multi-beam antennas in a satellite antenna coordinate system. The method provided by this invention can achieve the calibration of multi-beam antenna pointing deviation by adjusting the satellite attitude or the beamforming parameters of the phased array antenna.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system includes the following steps:

[0008] Step 1: Design the pointing vector of the beam group equal power overlap point in the satellite antenna coordinate system;

[0009] Step 2: Obtain the measured value of the satellite antenna pointing deviation through the measurement of the ground calibration station;

[0010] Step 3: Add the pointing vector of the equal power overlap point of the calibration beam group obtained in Step 1 and the measured value of the satellite antenna pointing deviation obtained in Step 2 to obtain the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment;

[0011] Step 4: Calculate the deviation of the satellite attitude angle based on the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment, the geographical location of the ground calibration station, the satellite orbit data, and the satellite antenna installation matrix;

[0012] Step 5: Based on the measured value of the satellite antenna pointing deviation obtained in Step 2 and the deviation value of the satellite attitude angle obtained in Step 4, establish a measurement model; perform periodic calibration of the satellite antenna pointing deviation based on the measurement model.

[0013] Furthermore, in step 1, the theoretical direction of the pointing vector of each calibration beam group's equal power overlap point at the nominal time is the ground calibration station.

[0014] Furthermore, the specific method for step 2 is as follows:

[0015] The ground calibration station calculates the power value of each beam signal received in the calibration group to obtain the measurement value of the satellite antenna pointing deviation; the measurement value of the satellite antenna pointing deviation belongs to the satellite antenna coordinate system and includes azimuth deviation and elevation deviation.

[0016] Furthermore, after obtaining the deviation value of the satellite attitude angle in step 4, the deviation value is converted into the adjustment value of the phased array antenna beamforming parameters; the measurement model in step 5 is established directly using the relationship between the measured value of the satellite antenna pointing deviation obtained in step 2 and the adjustment value of the phased array antenna beamforming parameters obtained in step 4.

[0017] Furthermore, step 4 is specifically implemented as follows:

[0018] Step 4-1: Calculate the coordinate vector of the geographical location of the ground calibration station in the Earth-Fixed System;

[0019] Step 4-2: Transform the coordinate vector of the geographical location of the ground calibration station in the Earth-Fixed coordinate system to the Southeast coordinate system through coordinate system transformation. This transformation includes the satellite orbit data.

[0020] Step 4-3: Transform the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment obtained in step 3 into the satellite body coordinate system;

[0021] Step 4-4: Based on the design values ​​of the satellite attitude angles, transform the results obtained in Step 4-3 to the southeast coordinate system;

[0022] Steps 4-5: Subtract the result obtained in the southeast coordinate system from the result obtained in step 4-2 from the result obtained in the southeast coordinate system from the result obtained in step 4-4 to obtain the deviation value of the satellite attitude angle;

[0023] Steps 4-6: Convert the deviation values ​​of the satellite attitude angle obtained in steps 4-5 into adjustment values ​​for the phased array antenna beamforming parameters.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The method of the present invention measures the antenna pointing deviation under the antenna coordinates of the satellite. Only the azimuth deviation and pitch deviation need to be measured. The accuracy of the yaw value is provided by other sensors other than the radio frequency sensor.

[0026] 2. This invention establishes a correlation between the measured values ​​of the ground calibration station and the attitude values ​​of the satellite. By adjusting the attitude values ​​of the satellite, the measured values ​​of the ground calibration station can be made to approach the theoretical design values, thereby calibrating the pointing deviation of the satellite antenna line of sight.

[0027] 3. This invention can calculate the pointing deviation of each beam center of the satellite multi-beam antenna by using the measurement values ​​of the ground calibration station and the design value of the pointing of each beam center of the satellite multi-beam antenna, and calibrate the pointing deviation of each beam center by adjusting the beamforming parameters of the phased array antenna. Implementation

[0028] The present invention will now be described in detail.

[0029] A method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system includes the following steps:

[0030] Step (1): Design the pointing vector of the equal power overlap point of the calibration beam group in the satellite antenna coordinate system; wherein, a satellite can design one or more calibration beam groups, and the theoretical pointing of the pointing vector of the equal power overlap point of each calibration beam group at the nominal time is the ground calibration station. The calibration beam in a calibration beam group consists of 3 or 4 beams, and the calibration signals of each beam in a calibration beam group occupy the same frequency, and are wirelessly transmitted through code division multiple access or time division multiple access.

[0031] Step (2): Obtain the measured value of the satellite antenna pointing deviation through the measurement of the ground calibration station; Step (2) specifically: The ground calibration station calculates the measured value of the satellite antenna pointing deviation by calculating the power value of each beam signal in the received calibration group; where the measured value of the satellite antenna pointing deviation belongs to the satellite antenna coordinate system, including azimuth deviation and elevation deviation. The coordinates of each ground calibration station in the satellite antenna coordinate system are related to the satellite's orbital parameters, the satellite platform's attitude parameters, and the deformation of the satellite antenna. The beam pointing deviation value obtained by ground measurement refers to the decomposition value of the angle between the actual coordinate vector of the ground calibration station in the satellite antenna coordinate system and the pointing vector of the equal power overlap point in the azimuth and elevation directions.

[0032] Step (3): The actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment is obtained by adding the pointing vector of the equal power overlap point of the calibration beam group obtained in step (1) and the measured value of the pointing deviation of the satellite antenna obtained in step (2);

[0033] Step (4): The deviation value of the satellite attitude angle is calculated based on the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment, the geographical location of the ground calibration station, the satellite orbit data and the satellite antenna installation matrix; further, the deviation value can be converted into the adjustment value of the phased array antenna beamforming parameters;

[0034] Step (4) specifically includes the following steps:

[0035] Step (4-1): Calculate the coordinate vector of the geographical location of the ground calibration station in the Earth-Fixed System;

[0036] Step (4-2): Transform the coordinate vector of the geographical location of the ground calibration station in the Earth-Fixed system to the Southeast coordinate system through coordinate system transformation. This transformation includes the satellite orbit data.

[0037] Step (4-3): Convert the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment obtained in step (3) to the satellite body coordinate system.

[0038] Step (4-4): Transform the results obtained in step (4-3) into the southeast coordinate system according to the design values ​​of the satellite attitude angle;

[0039] Step (4-5): Subtract the result obtained in the southeast coordinate system from the result obtained in the southeast coordinate system in step (4-2) to obtain the deviation value of the satellite attitude angle.

[0040] Step (4-6): Convert the deviation value of the satellite attitude angle obtained in step (4-5) into the adjustment value of the phased array antenna beamforming parameter.

[0041] Step (5): Establish a measurement model based on the relationship between the measured value of the satellite antenna pointing deviation obtained in Step (2) and the deviation value of the satellite attitude angle obtained in Step (4) (or the adjustment value of the phased array antenna beamforming parameters converted from the deviation value). According to the system's usage requirements, the satellite antenna pointing deviation is periodically calibrated using the measurement model.

[0042] In summary, this invention takes the measurement and calibration of the pointing deviation of the phased array multi-beam antenna of a mobile communication satellite as input, establishes a pointing measurement relationship model, uses the ground calibration station as a radio frequency sensor, and utilizes the relationship model between the ground calibration station and the satellite attitude to adjust the beam pointing of the phased array multi-beam antenna of the mobile communication satellite by adjusting the satellite attitude or the beamforming parameters of the phased array antenna, thereby achieving the calibration of the pointing deviation of the multi-beam antenna.

Claims

1. A method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system, characterized in that, Includes the following steps: Step 1: Design the pointing vector of the beam group equal power overlap point in the satellite antenna coordinate system; Step 2: Obtain the measured value of the satellite antenna pointing deviation through the measurement of the ground calibration station; Step 3: Add the pointing vector of the equal power overlap point of the calibration beam group obtained in Step 1 and the measured value of the satellite antenna pointing deviation obtained in Step 2 to obtain the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment; Step 4: Calculate the deviation of the satellite attitude angle based on the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment, the geographical location of the ground calibration station, the satellite orbit data, and the satellite antenna installation matrix; Step 5: Based on the measured value of the satellite antenna pointing deviation obtained in Step 2 and the deviation value of the satellite attitude angle obtained in Step 4, establish a measurement model; perform periodic calibration of the satellite antenna pointing deviation based on the measurement model.

2. The method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system according to claim 1, characterized in that, In step 1, the theoretical direction of the pointing vector of the equal power overlap point of each calibration beam group at the nominal time is the ground calibration station.

3. The method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system according to claim 1, characterized in that, The specific method for step 2 is as follows: The ground calibration station calculates the power value of each beam signal received in the calibration group to obtain the measurement value of the satellite antenna pointing deviation; the measurement value of the satellite antenna pointing deviation belongs to the satellite antenna coordinate system and includes azimuth deviation and elevation deviation.

4. The method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system according to claim 1, characterized in that, The specific method for step 4 is as follows: Step 4-1: Calculate the coordinate vector of the geographical location of the ground calibration station in the Earth-Fixed System; Step 4-2: Transform the coordinate vector of the geographical location of the ground calibration station in the Earth-Fixed coordinate system to the Southeast coordinate system through coordinate system transformation. This transformation includes the satellite orbit data. Step 4-3: Transform the actual pointing value of the ground calibration station in the satellite antenna coordinate system at each moment obtained in step 3 into the satellite body coordinate system; Step 4-4: Based on the design values ​​of the satellite attitude angles, transform the results obtained in Step 4-3 to the southeast coordinate system; Steps 4-5: Subtract the result obtained in the southeast coordinate system from the result obtained in step 4-2 from the result obtained in the southeast coordinate system from the result obtained in step 4-4 to obtain the deviation value of the satellite attitude angle; Steps 4-6: Convert the deviation values ​​of the satellite attitude angle obtained in steps 4-5 into adjustment values ​​for the phased array antenna beamforming parameters.

5. The method for measuring and calibrating the pointing deviation of a multi-beam antenna in a satellite antenna coordinate system according to claim 4, characterized in that, After obtaining the deviation value of the satellite attitude angle in step 4, the deviation value is converted into the adjustment value of the phased array antenna beamforming parameters; the measurement model in step 5 is established directly using the relationship between the measured value of the satellite antenna pointing deviation obtained in step 2 and the adjustment value of the phased array antenna beamforming parameters obtained in step 4.