Antenna beam pointing precision evaluation method

Abstract

The invention discloses an antenna beam pointing precision evaluation method, which comprises the following steps of: calculating a theoretical pointing angle of an antenna to a target direction, and measuring the actual pointing direction of the antenna by using measuring equipment; comparing the actual directional angle with the theoretical directional angle, and calculating an error between the two, namely the preliminarily evaluated beam directional precision; the preliminarily evaluated beam pointing precision is compared with the beam pointing precision obtained by the multi-pulse time-sharing beam pointing determination method, so that the error of the beam pointing precision obtained by the multi-pulse time-sharing beam pointing determination method is determined, and the beam pointing precision is obtained by combining the error with the multi-pulse time-sharing beam pointing determination method. And the actual antenna beam pointing precision can be quickly determined.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a method for evaluating antenna beam pointing accuracy. Background Art

[0002] Satellite antenna is one of the key components for satellite-ground communication. It is used to achieve high-speed data transmission to the ground station and is one of the key technologies for satellites to achieve reliable data transmission between the satellite and the ground. With the continuous improvement of the demand for space missions, higher and higher requirements are placed on the pointing and tracking capabilities of antennas. The satellite system is required to adjust the pointing direction of the antenna according to instructions and track the target in order to capture the signal in the designated area on the ground. At the same time, with the rapid development of my country's space technology, the amount of data acquired by high-resolution satellite remote sensors is increasing, and the working life of satellites in orbit is also increasing. The requirements of satellites for antenna data transmission capabilities, beam coverage capabilities, pointing accuracy and working life are also increasing. When the onboard antenna communicates between the satellite and the ground station, it needs to accurately point to the target to ensure that the signal reception is always in the best receiving state. The pointing accuracy of the antenna has become one of the most important performance indicators of the antenna. Its indicator is a crucial content for whether the design of the satellite communication system meets the requirements. If the accuracy does not meet the requirements, it will directly affect the use of the antenna and thus fail to complete the scheduled task.

[0003] However, in the prior art, an evaluation model for antenna pointing accuracy is often obtained through onboard telemetry data during ground testing, and multiple evaluations require multiple acquisitions. The model error problem needs to be considered during each evaluation process. Error calculation will lead to low model evaluation efficiency during long-term use. Summary of the invention

[0004] The purpose of the present invention is to provide a method for evaluating antenna beam pointing accuracy to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for evaluating antenna beam pointing accuracy, comprising the following steps:

[0006] 1) Preprocessing of telemetry data acquired by satellite or ground test equipment;

[0007] 2) Calculate the coordinate transformation matrix to transform the preprocessed data from the original coordinate system to the antenna coordinate system in order to accurately calculate the beam pointing;

[0008] 3) Calculate the theoretical pointing angle of the antenna to the target direction based on the data with consistent time codes and the coordinate conversion matrix, and use the measuring equipment to measure the actual pointing angle of the antenna;

[0009] 4) Compare the actual pointing angle with the theoretical pointing angle and calculate the error between the two, which is the preliminary evaluation of the beam pointing accuracy;

[0010] 5) Using a multi-pulse time-sharing beam pointing determination method to obtain beam pointing accuracy;

[0011] 6) By comparing the beam pointing accuracy of the preliminary evaluation with the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method, the error of the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method is determined. When the antenna beam pointing is determined again, the antenna beam pointing accuracy can be quickly determined by combining the error with the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method.

[0012] Preferably, the data preprocessing in step 1) includes interpolation processing, and the specific steps of the interpolation method are:

[0013] Find the intervals in the data set that need to be interpolated, that is, the blank areas between known data points or the areas containing outliers;

[0014] After determining the interpolation interval, collect the known data points at both ends of the interval;

[0015] Construct an interpolation function based on the selected interpolation method and known data points;

[0016] Select or generate interpolation points within the interpolation interval, substitute the coordinates of the interpolation points into the interpolation function, and calculate the corresponding interpolation results;

[0017] The above interpolation function formula is:

[0018] Where (x1, y1) and (x2, y2) are known data points, (x, y) is an interpolation point inserted between them, where x1 <x<x2;

[0019] The interpolation result can be obtained according to the above formula.

[0020] Preferably, the specific steps of step 2) include:

[0021] Collect transformation parameters, including ellipsoid parameters, zone standards, and longitude of the central meridian;

[0022] Perform coordinate conversion to convert the latitude, longitude and geodetic height of the starting coordinate system into spatial rectangular coordinates;

[0023] If the starting coordinate system and the target coordinate system belong to different ellipsoids, they are converted into spatial rectangular coordinates by Datum conversion.

[0024] After completing the Datum conversion, if the target coordinate system is the geodetic coordinate system, the converted spatial rectangular coordinates need to be converted back to geodetic coordinates; if the target coordinate system is a plane rectangular coordinate system, Gauss projection calculation is required to convert the geodetic coordinates into plane rectangular coordinates.

[0025] Preferably, the measuring equipment used in step 3) includes a phase meter and an angle encoder.

[0026] Preferably, the specific steps of step 5) are: four beacon beams are generated on the satellite in time-sharing manner, one ground receiver is arranged at the center of the four beacon beams, the antenna forms four beacon beams through different feed source combinations, which are two beacon beams symmetrical in distance and two beacon beams symmetrical in azimuth, and beacon pulse signals are sent to the ground receiver in turn. After the receiver receives the beacon pulse signal, it calculates the azimuth pointing deviation through sum and difference beam processing, thereby determining the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method.

[0027] Preferably, the error of the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method in step 6) includes a satellite attitude measurement error and a three-dimensional systematic error.

[0028] Preferably, the errors obtained in step 6) are used to establish a database, and after the beam pointing accuracy is obtained by the multi-pulse time-sharing beam pointing determination method, the error data in the database is matched, and the actual antenna beam pointing accuracy can be obtained by removing the error data.

[0029] The technical effects and advantages of the present invention are as follows: the antenna beam pointing accuracy evaluation method adopts an interpolation processing method to supplement missing data points, so as to make the data more complete and ensure the accuracy of subsequent antenna beam pointing accuracy calculations; the preliminary evaluation result of the antenna beam pointing accuracy is determined through theoretical pointing calculations and actual pointing calculations, and the error of the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method is determined by comparing the preliminary evaluated beam pointing accuracy with the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method, and the actual antenna beam pointing accuracy can be quickly determined through the error. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] The present invention provides Figure 1 A method for evaluating antenna beam pointing accuracy is shown, comprising the following steps:

[0033] Step 1: Data preprocessing:

[0034] Processing of telemetry data acquired by satellites or ground test equipment to ensure time code consistency, i.e. all measurement data are under the same time reference;

[0035] Use high-precision time calibration equipment (such as GPS receivers, atomic clocks, etc.) to calibrate the satellite and ground test equipment to ensure that their clock errors are within an acceptable range.

[0036] After receiving the signal, the satellite or ground test equipment will record the telemetry data according to the preset sampling rate and format. This data usually includes key information such as timestamp, signal strength, phase, frequency, etc.

[0037] Ensure that each data point is accompanied by an accurate timestamp that is consistent with the device's time base.

[0038] All measurement data are sorted and aligned in chronological order according to the timestamps.

[0039] For data points with time differences, time correction can be performed through interpolation to ensure that all data are compared and analyzed based on the same time reference.

[0040] The specific steps of the interpolation method are:

[0041] Find the intervals in the data set that need to be interpolated, that is, the blank areas between known data points or the areas containing outliers;

[0042] After determining the interpolation interval, collect the known data points at both ends of the interval;

[0043] Construct an interpolation function based on the selected interpolation method and known data points;

[0044] Select or generate interpolation points within the interpolation interval, substitute the coordinates of the interpolation points into the interpolation function, and calculate the corresponding interpolation results;

[0045] The above interpolation function formula is:

[0046] Where (x1, y1) and (x2, y2) are known data points, (x, y) is an interpolation point inserted between them, where x1 <x<x2;

[0047] The interpolation result can be obtained according to the above formula.

[0048] Step 2: Coordinate transformation

[0049] Transform telemetry data from the original coordinate system to the antenna coordinate system to accurately calculate beam pointing; specifically,

[0050] Collect conversion parameters: According to the conversion requirements, collect necessary conversion parameters, which may include ellipsoid parameters, zoning standards, longitude of the central meridian, etc. For conversion between different ellipsoids, the conversion of Datum (reference surface) also needs to be considered;

[0051] Perform coordinate conversion: convert the latitude and longitude (B, L) and geodetic height (H) of the starting coordinate system into spatial rectangular coordinates (X, Y, Z);

[0052] If the starting coordinate system and the target coordinate system belong to different ellipsoids, they are converted into spatial rectangular coordinates by Datum conversion.

[0053] After completing the Datum conversion, if the target coordinate system is a geodetic coordinate system, the converted spatial rectangular coordinates (X, Y, Z) need to be converted back to geodetic coordinates (B', L', H'); if the target coordinate system is a plane rectangular coordinate system, Gauss projection calculation is required to convert the geodetic coordinates (B', L') into plane rectangular coordinates;

[0054] After completing the coordinate transformation, the transformation results should be verified using known control point coordinates to ensure the accuracy and reliability of the transformation.

[0055] Step 3: Preliminary evaluation of pointing accuracy

[0056] Theory points to calculation:

[0057] Based on the data and coordinate conversion with consistent time codes, the theoretical pointing angle of the antenna to the target direction is calculated using the mathematical model of the phased array antenna (usually involving the calculation of trigonometric functions).

[0058] Actual pointing measurement:

[0059] Use high-precision measuring equipment (such as phase meters, angle encoders, etc.) to measure the actual pointing direction of the antenna; ensure the stability and accuracy of the measuring equipment during the test and avoid the influence of external interference on the measurement results.

[0060] The actual pointing angle is compared with the theoretical pointing angle, and the error between the two is calculated, which is the preliminary evaluation of the beam pointing accuracy.

[0061] Step 4: Multi-pulse time-sharing beam pointing determination method to obtain beam pointing accuracy

[0062] The multi-pulse time-sharing beam pointing determination method calculates the pointing deviations of the antenna beam in the range and azimuth directions. First, four beacon beams and a single-antenna ground receiver are generated on the satellite in a time-sharing manner. The ground receiver is arranged at the center of the four beacon beams. The antenna forms four beacon beams through different feed combinations, which are two beacon beams symmetrical in the range and two beacon beams symmetrical in the azimuth directions. Beacon pulse signals are sent to the ground receiver in sequence. After the receiver receives the beacon pulse signal, the pointing deviations of the antenna beam in the range and azimuth directions can be estimated respectively through sum and difference beam processing, thereby determining the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method.

[0063] Step 5, obtaining the actual beam pointing accuracy by combining the error with the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method;

[0064] By comparing the beam pointing accuracy of the preliminary evaluation with the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method, the error of the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method is determined, and the error includes satellite attitude measurement error, three-dimensional systematic error, etc.

[0065] The error at each position is obtained and a database is established. When the antenna beam pointing is determined again, the error data of the position is obtained from the database to determine the actual antenna beam pointing accuracy, which greatly improves the efficiency and accuracy of the subsequent antenna beam pointing accuracy assessment.

[0066] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for evaluating antenna beam pointing accuracy, characterized in that: The steps include: 1) Preprocessing of telemetry data acquired by satellite or ground test equipment; 2) Calculate the coordinate transformation matrix to transform the preprocessed data from the original coordinate system to the antenna coordinate system in order to accurately calculate the beam pointing; 3) Calculate the theoretical pointing angle of the antenna to the target direction based on the data with consistent time codes and the coordinate conversion matrix, and use the measuring equipment to measure the actual pointing angle of the antenna; 4) Compare the actual pointing angle with the theoretical pointing angle and calculate the error between the two, which is the preliminary evaluation of the beam pointing accuracy; 5) Using a multi-pulse time-sharing beam pointing determination method to obtain beam pointing accuracy; 6) By comparing the beam pointing accuracy of the preliminary evaluation with the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method, the error of the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method is determined. When the antenna beam pointing is determined again, the antenna beam pointing accuracy is quickly determined by combining the error with the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method.

2. The method for evaluating antenna beam pointing accuracy according to claim 1, characterized in that: The data preprocessing in step 1) includes interpolation processing, and the specific steps of the interpolation method are: Find the intervals in the data set that need to be interpolated, that is, the blank areas between known data points or the areas containing outliers; After determining the interpolation interval, collect the known data points at both ends of the interval; Construct an interpolation function based on the selected interpolation method and known data points; Select or generate interpolation points within the interpolation interval, substitute the coordinates of the interpolation points into the interpolation function, and calculate the corresponding interpolation results; The above interpolation function formula is: Where (x1, y1) and (x2, y2) are known data points, (x, y) is an interpolation point inserted between them, where x1 <x<x2; The interpolation result can be obtained according to the above formula.

3. The method for evaluating antenna beam pointing accuracy according to claim 1, characterized in that: The specific steps of step 2) include: Collect transformation parameters, including ellipsoid parameters, zone standards, and longitude of the central meridian; Perform coordinate conversion to convert the latitude, longitude and geodetic height of the starting coordinate system into spatial rectangular coordinates; If the starting coordinate system and the target coordinate system belong to different ellipsoids, they are converted into spatial rectangular coordinates by Datum conversion. After completing the Datum conversion, if the target coordinate system is the geodetic coordinate system, the converted spatial rectangular coordinates need to be converted back to geodetic coordinates; if the target coordinate system is a plane rectangular coordinate system, Gauss projection calculation is required to convert the geodetic coordinates into plane rectangular coordinates.

4. The method for evaluating antenna beam pointing accuracy according to claim 1, characterized in that: The measuring equipment used in step 3) includes a phase meter and an angle encoder.

5. The method for evaluating antenna beam pointing accuracy according to claim 1, characterized in that: The specific steps of step 5) are as follows: four beacon beams are generated on the satellite in time-sharing manner, one ground receiver is arranged at the center of the four beacon beams, the antenna forms four beacon beams through different feed source combinations, namely two beacon beams symmetrical in distance and two beacon beams symmetrical in azimuth, and beacon pulse signals are sent to the ground receiver in sequence. After the receiver receives the beacon pulse signal, the azimuth pointing deviation is calculated through sum and difference beam processing, thereby determining the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method.

6. The method for evaluating antenna beam pointing accuracy according to claim 1, characterized in that: The error of the beam pointing accuracy obtained by the multi-pulse time-sharing beam pointing determination method in step 6) includes satellite attitude measurement error and three-dimensional systematic error.

7. The method for evaluating antenna beam pointing accuracy according to claim 1, characterized in that: The error obtained in step 6) is used to establish a database. After the beam pointing accuracy is obtained by the multi-pulse time-sharing beam pointing determination method, the error data in the database is matched, and the actual antenna beam pointing accuracy can be obtained by removing the error data.

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