Interferometer antenna position precision optimization method

Abstract

The invention relates to an interferometer antenna position precision optimization method, which comprises the following steps of: S1, after the state of an antenna is checked, installing the antenna in place; s2, performing position precision optimization on the antenna according to two states of a floor and an extension rod mechanism through different methods; s3, binding antenna coordinate positions; and S4, completing on-orbit calibration, further reducing the influence of the antenna installation error on the positioning precision, and completing the optimization of the positioning precision. According to the invention, the influence of the antenna installation error is reduced, the direction finding accuracy of the satellite load direction finding system is improved, and the positioning precision of the satellite is greatly improved from the perspective of satellite application and satellite efficiency.

Description

Technical Field

[0001] The present invention relates to the field of satellite positioning technology, and in particular to a method for optimizing the position accuracy of an interferometer antenna. Background Art

[0002] The principle of interferometer direction finding and positioning technology is to use the phase difference formed by radio waves on the direction finding baseline to determine the direction of the incoming wave. For the interferometer direction finding system, common array forms include: uniform circular array; non-uniform linear array; "L-shaped, T-shaped, cross-shaped" orthogonal array, irregular array, etc. Compared with the linear array, the circular array has the advantages of no mirror ambiguity, independent angular resolution, and omnidirectional direction finding. The non-uniform linear array and the "L-shaped, T-shaped, cross-shaped" orthogonal array can further achieve full-band and omnidirectional direction finding by optimizing the baseline selection of the antenna array.

[0003] In order to achieve high-precision positioning functions in multiple frequency bands and improve system capabilities, a combination of long and short baselines can be used: although the long baseline has multiple phase values, that is, "phase ambiguity", the actual phase can be solved using the short baseline. The longer the long baseline, the more antenna elements are required for deambiguation, and the higher the direction-finding accuracy of the system. By combining different formations, long and short baselines are established on the satellite structure, and an extension mechanism is added to extend the baseline length when necessary, deambiguation and direction-finding can be achieved to meet positioning needs.

[0004] In the process of positioning and solving, the fixed multi-baseline interferometer direction-finding positioning system measures the arrival time and frequency of the target signal and the phase difference between the interferometer antenna and the target signal. The target position is estimated based on time and combined with orbital position information and interferometer antenna installation information. The above observation information will affect the positioning accuracy due to various errors such as system error, algorithm error and mechanical error, and must be corrected.

[0005] Therefore, designing a method to optimize the position accuracy of interferometer antenna is a technical problem that needs to be solved urgently. Summary of the invention

[0006] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for optimizing the position accuracy of an interferometer antenna, which can improve the positioning accuracy of a satellite for a target.

[0007] To achieve the above-mentioned object of the invention, the present invention provides a method for optimizing the position accuracy of an interferometer antenna, comprising the following steps:

[0008] Step S1, after completing the inspection of the antenna status, install the antenna in place;

[0009] Step S2, optimizing the position accuracy of the antenna in two states, the floor and the extension rod mechanism, by different methods;

[0010] Step S3, binding the antenna coordinate position;

[0011] Step S4: complete on-orbit calibration to further reduce the impact of antenna installation errors on positioning accuracy and optimize positioning accuracy.

[0012] According to a technical solution of the present invention, in step S1, the status of the antenna is checked to ensure that the antenna surface is intact, without bumps and scratches, without surface shedding and damage, without excess objects, and the markings are clear, visible and correct.

[0013] According to a technical solution of the present invention, in step S2, after the antenna is installed in place, industrial photogrammetry is performed on the antenna installed on the floor, including:

[0014] Stick circular markers / targets regularly on the surface of all antennas;

[0015] According to the requirements of industrial photography, a reference ruler should be placed near the object to be measured, and the reference ruler should be placed at the bottom of the antenna array surface on the ground to be measured;

[0016] Use the lifting device to collect photographic images around the satellite;

[0017] Process the photographic image, combine it with the length information of the reference ruler, establish a measurement data model, and calculate the coordinates of the antenna on the floor;

[0018] It is determined whether the accuracy meets the requirement. If so, the step S3 is executed. If not, the position of the floor antenna is adjusted and the accuracy of the floor antenna is optimized again.

[0019] According to a technical solution of the present invention, in step S2, after the antenna is installed in place, a precision measurement of the extension mechanism is performed, including:

[0020] Measure and calculate the transformation matrix from the antenna installation coordinate system to the R hole of the deployment arm: R A-R ,X A-R .

[0021] A measuring and detection mirror is installed at the root of the extension rod mechanism as a reference for the coordinate conversion of the extension rod mechanism to the satellite body coordinate system. The conversion matrix from the R hole of the deployment arm to the newly added cubic mirror is measured and calculated: R R-XZ ,X R-XZ ;

[0022] Taking the parking surface of the satellite support vehicle as the reference of the whole satellite, the center point of the four docking joints is the origin of the coordinate axis, and the upward direction is positive. Calculate the conversion matrix from the newly added cubic mirror to the whole satellite: R XZ-X , X XZ-X ;

[0023] The antenna coordinates of the extension rod mechanism are converted to the stellar coordinate system, that is, the coordinate system is converted from O x1,y1,z1 Convert to O x2,y2,z2 , then:

[0024]

[0025] Among them, M represents the rotation transformation in the matrix transformation, usually using Euler rotation; x0, y0, z0 represent the translation transformation, and M is expressed as:

[0026]

[0027] After the antenna position is calculated, its installation accuracy is evaluated. If the installation accuracy does not meet the requirements, it is necessary to adjust the installation position of the antenna and re-optimize the accuracy of the antenna of the extension mechanism.

[0028] According to a technical solution of the present invention, in step S3, the adjusted extension rod mechanism and the position coordinate information of all antennas on the ground are bound to the satellite payload direction finding system.

[0029] According to a technical solution of the present invention, in step S4, the phase difference system error Δφ, the interferometer baseline length system error Δd, the interferometer azimuth angle system error Δθ, and the interferometer elevation angle system error Δε of the direction-finding system are estimated by a ground calibration station to correct the positioning result.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] After the antenna is installed, the present invention actually measures and adjusts the installation accuracy of the antenna instead of using the theoretical position coordinates of the antenna installation, which greatly reduces the impact of antenna installation errors and improves the direction finding accuracy of the satellite direction finding system. From the perspective of satellite application and satellite efficiency, the positioning accuracy of the satellite is greatly improved.

[0032] During the actual measurement of the antenna position coordinates, the position measurement link is decomposed into the extension rod mechanism and the ground plane. The accuracy of the antenna on the installation surface of the extension rod mechanism, the installation accuracy of the extension rod mechanism and the ground plane, and the accuracy of the antenna on the installation surface of the ground plane are all optimized. Factors such as structural deformation and vibration that may exist in the satellite development process are taken into account, reducing the cumulative error of the antenna position.

[0033] When designing the satellite payload direction finding system, a system error model was established to correct the antenna installation error to a certain extent. When the error exceeds a certain range, the complexity of the correction algorithm increases significantly, and the processing power requirements of the system increase sharply. After measuring and adjusting the installation position of the antenna, the installation error of the antenna can meet the processing power of the algorithm, effectively saving economic costs.

[0034] This method was first proposed and applied in a fixed multi-baseline interferometer direction finding positioning system, and its application effect has been verified by satellite in-orbit applications. This method can provide research ideas for subsequent satellites with the same system or in the same field. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A schematic diagram of interferometer antenna position layout according to an embodiment of the present invention is schematically shown;

[0037] Figure 2 A schematic diagram of an antenna position accuracy optimization flow chart according to an embodiment of the present invention is shown;

[0038] Figure 3 Schematically showing a schematic diagram of antenna x-axis installation deviation according to an embodiment of the present invention;

[0039] Figure 4 The effect of antenna x-axis installation deviation according to one embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0041] like Figure 1 As shown, an interferometer antenna position accuracy optimization method of the present invention is suitable for optimizing the position accuracy of satellite antennas in a fixed multi-baseline interferometer direction-finding positioning system. The antennas are arranged in a combination of multiple formations, and antennas of different formations are respectively located on the satellite extension rod mechanism and the satellite ground plane. The position accuracy of antennas in the two installation states is optimized respectively, thereby fundamentally eliminating the influence of antenna installation errors on positioning accuracy.

[0042] For the antenna on the satellite ground, the sources of position error include: installation error of the antenna on the installation surface, installation error between the antenna installation surface and the satellite body, deviation caused by satellite vibration and thermal change, etc.; for the antenna on the satellite extension mechanism, the sources of position error include: installation error of the antenna on the extension mechanism, mechanism optimization accuracy, mechanism vibration, thermal deformation, etc. causing antenna position deviation.

[0043] An interferometer antenna position accuracy optimization method of the present invention comprises the following steps:

[0044] Step S1, after completing the inspection of the antenna status, install the antenna in place;

[0045] Step S2, optimizing the position accuracy of the antenna in two states, the floor and the extension rod mechanism, by different methods;

[0046] Step S3, binding the antenna coordinate position;

[0047] Step S4: complete on-orbit calibration to further reduce the impact of antenna installation errors on positioning accuracy and optimize positioning accuracy.

[0048] In some embodiments of the present invention, the step S1 checks the status of the antenna to ensure that the antenna surface is intact, without bumps and scratches, without surface shedding and damage, without excess objects, and the markings are clear, visible and correct. Otherwise, the antenna needs to be processed before it can be installed.

[0049] The installation position of the antenna is optimized according to the accuracy of the floor and the extension mechanism. The optimization process is as follows: Figure 2 The antenna on the floor is photographed from multiple angles and viewed using an industrial photogrammetry system. Figure 3 The antenna on the extension rod mechanism is precisely measured and coordinate transformed in two dimensions of the extension rod mechanism and the satellite structure to achieve accuracy optimization. In some embodiments of the present invention, in step S2, for the satellite to the antenna on the ground, the industrial photogrammetry technology is used to optimize its position accuracy, including:

[0050] (1) After the antenna installation is in place, industrial photogrammetry technology is implemented for the antenna on the floor. First, circular markers / targets are regularly pasted on the surface of all antennas to evenly cover the antenna surface to facilitate the full and accurate extraction of image information. Markers are also pasted on the floor surface. When pasting the markers, care should be taken to avoid obstruction.

[0051] (2) According to the requirements of industrial photography, a reference ruler should be placed near the object to be measured. The reference ruler should be placed at the bottom of the antenna array of the measured floor, and the targets at both ends of the reference ruler should not be blocked after being placed, so as to provide a length reference for the measurement process.

[0052] (3) Since the image capture needs to meet the requirements of multiple angles and multiple images, the use of a lifting device to collect photographic images around the satellite requires that the lifting device can at least be raised to the same height as the top antenna and that the lifting device be controlled to move freely within a certain range from the satellite. Check the captured images and, if necessary, retake them to ensure the integrity of the modeling data.

[0053] (4) Process the photographic image, combine it with the length information of the reference ruler, establish a measurement data model, and calculate the coordinates of the antenna on the floor. Compare it with the theoretical value to confirm the installation deviation. If the deviation is large, the antenna position needs to be adjusted.

[0054] (5) After the measurement / adjustment is completed, remove the antenna and the target on the floor, and confirm again that the antenna and the floor surface are intact and free of excess material. This completes the measurement.

[0055] The process of implementing satellite precision measurement mainly includes establishing mechanical benchmarks and optical benchmarks, wherein the optical benchmark is a measuring and detecting mirror installed on the entire satellite structure or equipment, i.e., a cubic mirror. In some embodiments of the present invention, in step S2, for the antenna on the extension rod mechanism, a satellite precision measurement system is used in combination with a coordinate conversion algorithm to convert the antenna position coordinates on the extension rod mechanism to the satellite body coordinate system through the measurement and detection mirror, R hole and other benchmarks, and compare them with the theoretical design value to confirm the installation error, including:

[0056] (1) After confirming that the antenna is in the correct state and installed in place, carry out precision measurement of the extension mechanism. Measure and calculate the transformation matrix from the antenna installation coordinate system to the R hole of the extension mechanism, expressed as: R A-R ,X A- R.

[0057] (2) Install a measuring and detection mirror (newly added cubic mirror) at the root of the extension rod mechanism as the reference for the extension rod mechanism coordinate transformation to the satellite body coordinate system. Measure and calculate the transformation matrix from the extension rod mechanism R hole to the newly added cubic mirror, expressed as: R R-XZ ,X R-XZ .

[0058] (3) Carry out precision measurement of the whole satellite: Take the parking surface of the satellite support vehicle as the reference of the whole satellite, the center point of the line connecting the four docking joints is the origin of the coordinate axis, and the upward direction is positive. Calculate the conversion matrix from the newly added cubic mirror to the whole satellite, expressed as: R XZ-X , X XZ-X .

[0059] (4) The conversion matrix calculated by the above steps (1) to (3) is used to transform the antenna coordinates on the extension rod mechanism into the stellar coordinate system by using the rotation and translation transformation of the matrix. That is, the coordinate system is transformed from O x1,y1,z1 Convert to O x2,y2,z2, then:

[0060]

[0061] Among them, M represents the rotation transformation in the matrix transformation, usually using Euler rotation; x0, y0, z0 represent the translation transformation, and M is expressed as:

[0062]

[0063] (5) After the antenna position is calculated, its installation accuracy is evaluated. If the installation accuracy does not meet the requirements, the antenna installation position needs to be adjusted.

[0064] In some embodiments of the present invention, in step S3, after the floor and telescopic antennas are measured and adjusted, the coordinates of all antennas are unified to the satellite body coordinate system and bound to the satellite payload direction finding system. It is ensured that the interferometer baseline length, interferometer baseline azimuth angle, and interferometer baseline pitch angle errors are within the specification range.

[0065] The specific process can be expressed as:

[0066] (1) For antennas installed on the ground, the position coordinates are calculated by industrial photogrammetry system. Marking points (targets) are regularly pasted on the surface of the antenna to be measured, and the reference ruler required for measurement is placed at the bottom of the antenna array. Multiple images are taken from multiple angles, and the image data is processed to determine the actual coordinates of the antenna on the ground and confirm the installation error.

[0067] (2) For the antenna on the extension rod mechanism, use the precision measurement system to measure its installation position on the extension rod mechanism and convert the antenna installation coordinates to the extension rod mechanism coordinate system; through the measurement between different cubic mirrors, convert the antenna coordinates on the extension rod mechanism to the satellite body coordinate system again and compare them with the theoretical design value to confirm the installation error;

[0068] (4) If the error exceeds the threshold, the position of the antenna needs to be adjusted to optimize its installation accuracy and adjust it to within the error index range of the satellite payload direction finding system;

[0069] (5) After completing the measurement / adjustment of all interferometer antennas, record the correct position coordinates and bind the coordinates to the satellite payload direction finding positioning system for use in subsequent direction finding processing. Figure 3 This is a schematic diagram showing the deviation of the antenna x-axis installation. Figure 4 This is the effect of the antenna x-axis installation deviation on the phase deviation. When the antenna installation has deviation, it has a great impact on the phase accuracy of the interferometer, so the antenna installation accuracy needs to be strictly controlled.

[0070] After the satellite enters orbit, the systematic error of direction finding and positioning may still change due to environmental changes and vibration processes, so it is necessary to perform on-orbit calibration to correct the direction finding and positioning results. Among them, the deviations caused by the phase difference systematic error, interferometer baseline length systematic error, interferometer azimuth systematic error, and interferometer elevation angle systematic error are usually large.

[0071] In some embodiments of the present invention, in step S4, in order to further improve the positioning accuracy, the factors causing the positioning error are comprehensively considered: phase difference measurement error, interferometer baseline length measurement error, interferometer baseline installation angle error, observation platform attitude error, observation platform position error, frequency measurement error, etc. The error model is established using the error factors with greater influence: phase difference system error Δφ, interferometer baseline length system error Δd, interferometer azimuth angle system error Δθ, interferometer pitch angle system error Δε:

[0072]

[0073] One or more calibration stations are established on the ground. After the satellite enters orbit, the two prior information of the known location of the calibration station and the known signal frequency can be used to estimate four correction quantities through long-term observation to correct the direction-finding and positioning results in the process of solving the unknown radiation source position.

[0074] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention, and therefore the present invention is not limited to the above specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. A method for optimizing the position accuracy of an interferometer antenna, characterized in that: The following steps are involved: Step S1, after completing the inspection of the antenna status, install the antenna in place; Step S2, optimizing the position accuracy of the antenna in two states, the floor and the extension rod mechanism, by different methods; Step S3, binding the antenna coordinate position; Step S4: complete on-orbit calibration to further reduce the impact of antenna installation errors on positioning accuracy and optimize positioning accuracy.

2. The interferometer antenna position accuracy optimization method according to claim 1, characterized in that: In step S1, the status of the antenna is checked to ensure that the antenna surface is intact, without any bumps or scratches, without any surface shedding or damage, without any extraneous materials, and the markings are clear, visible and correct.

3. The interferometer antenna position accuracy optimization method according to claim 1, characterized in that: In step S2, after the antenna is installed in place, industrial photogrammetry is performed on the antenna installed on the floor, including: Stick circular markers / targets regularly on the surface of all antennas; According to the requirements of industrial photography, a reference ruler should be placed near the object to be measured, and the reference ruler should be placed at the bottom of the antenna array surface on the ground to be measured; Use the lifting device to collect photographic images around the satellite; Process the photographic image, combine it with the length information of the reference ruler, establish a measurement data model, and calculate the coordinates of the antenna on the floor; It is determined whether the accuracy meets the requirement. If so, the step S3 is executed. If not, the position of the floor antenna is adjusted and the accuracy of the floor antenna is optimized again.

4. The interferometer antenna position accuracy optimization method according to claim 1, characterized in that: In step S2, after the antenna is installed in place, a precision test of the extension mechanism is performed, including: Measure and calculate the transformation matrix from the antenna installation coordinate system to the R hole of the deployment arm: R A-R ,X A-R . A measuring and detection mirror is installed at the root of the extension rod mechanism as a reference for the coordinate conversion of the extension rod mechanism to the satellite body coordinate system. The conversion matrix from the R hole of the deployment arm to the newly added cubic mirror is measured and calculated: R R-XZ ,X R-XZ ; Taking the parking surface of the satellite support vehicle as the reference of the whole satellite, the center point of the four docking joints is the origin of the coordinate axis, and the upward direction is positive. Calculate the conversion matrix from the newly added cubic mirror to the whole satellite: R XZ-X , X XZ-X ; The antenna coordinates of the extension rod mechanism are converted to the stellar coordinate system, that is, the coordinate system is converted from O x1,y1,z1 Convert to O x2,y2,z2 , then: Among them, M represents the rotation transformation in the matrix transformation, usually using Euler rotation; x0, y0, z0 represent the translation transformation, and M is expressed as: After the antenna position is calculated, its installation accuracy is evaluated. If the installation accuracy does not meet the requirements, it is necessary to adjust the installation position of the antenna and re-optimize the accuracy of the antenna of the extension mechanism.

5. The interferometer antenna position accuracy optimization method according to claim 1, characterized in that: In step S3, the adjusted extension rod mechanism and the position coordinate information of all antennas on the ground are bound to the satellite payload direction finding system.

6. The interferometer antenna position accuracy optimization method according to claim 1, characterized in that: In step S4, the phase difference systematic error Δφ of the direction finding system, the interferometer baseline length systematic error Δd, the interferometer azimuth systematic error Δθ, and the interferometer elevation angle systematic error Δε are estimated by a ground calibration station to correct the positioning result.

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