An interferometer antenna position accuracy optimization method

Abstract

The application relates to an interferometer antenna position precision optimization method, which comprises the following steps: S1, after the state of an antenna is checked, the antenna is installed in place; S2, the antenna is positioned in precision according to two states of a floor and a telescopic rod mechanism through different methods; S3, antenna coordinate position is bound; and S4, in-orbit calibration is completed, the influence of antenna installation error on positioning precision is further reduced, and positioning precision optimization is completed. The application reduces the influence of antenna installation error, improves the direction finding accuracy of a satellite load direction finding system, and greatly improves the positioning precision of the satellite from the angles of satellite application and satellite efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite positioning technology, in particular to an interferometer antenna position precision optimization method. BACKGROUND

[0002] The principle of interferometer direction finding positioning technology is to determine the direction of arrival of radio waves by using the phase difference formed by the radio waves on the direction finding baseline. For the interferometer direction finding system, the common array forms include: uniform circular array, non-uniform linear array, "L-shaped, T-shaped, ten-shaped" orthogonal array, irregular array, etc. The circular array has the advantages of no mirror image ambiguity, independent angle resolution capability, and all-directional direction finding compared with the linear array. The non-uniform linear array and the "L-shaped, T-shaped, ten-shaped" orthogonal array can further realize full-band and all-directional direction finding by optimizing the selection of the baseline of the antenna array.

[0003] To realize multi-band high-precision positioning function and improve system capability, a long-short baseline combination method can be used. Although the long baseline has the problem of phase multi-value, that is, "phase ambiguity", the actual phase can be solved by using the short baseline. The longer the long baseline is, the more antenna elements are needed to solve the ambiguity, and the higher the direction finding precision of the system is. By combining different array forms, long-short baselines are established on the satellite structure, and the baseline length is extended by increasing the extension mechanism if necessary, so that the ambiguity and direction finding can be realized to meet the positioning requirements.

[0004] In the positioning solution process of this fixed multi-baseline interferometer direction finding positioning system, the direction finding positioning system measures the time of arrival of the target signal, the frequency, and the phase difference between the interferometer antennas receiving the target signal. Based on time, combined with orbit position information and interferometer antenna installation information, the target position estimation is completed. The above observation information will be affected by system errors, algorithm errors, and mechanical errors, and must be corrected.

[0005] Therefore, it is a technical problem to be solved to design an interferometer antenna position precision optimization method. SUMMARY

[0006] To solve the technical problems in the prior art, the purpose of the present application is to provide an interferometer antenna position precision optimization method, which can improve the positioning precision of the satellite to the target.

[0007] To achieve the above application purpose, the present application provides an interferometer antenna position precision optimization method, which comprises the following steps:

[0008] Step S1, after checking the state of the antenna, install the antenna in place;

[0009] Step S2, optimize the position precision of the antenna in two states of the ground plate and the extension rod mechanism by different methods.

[0010] Step S3, antenna coordinate position binding;

[0011] Step S4, complete on-orbit calibration, further reduce the influence of antenna installation error on positioning accuracy, complete positioning accuracy optimization.

[0012] According to one of the technical solutions of the application, in the step S1, the state of the antenna is checked to ensure that the antenna surface is intact, without scratches, no surface peeling and damage, no excess, and the label is clear and correct.

[0013] According to one of the technical solutions of the application, in the step S2, after the antenna is installed in place, the antenna installed on the ground plate is measured by industrial photogrammetry, including:

[0014] Regularly paste circular mark points / targets on the surface of all antennas;

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

[0016] Photographic images are collected around the satellite using a lifting device;

[0017] The photographic images are processed, combined with the length information of the reference ruler, a measurement data model is established, and the coordinates of the antenna on the ground plate are calculated;

[0018] Judge whether the accuracy meets the requirements, if yes, execute the step S3, if not, adjust the position of the ground plate antenna, and re-optimize the accuracy of the ground plate antenna.

[0019] According to one of the technical solutions of the application, in the step S2, after the antenna is installed in place, the precision measurement of the stretching rod mechanism is performed, including:

[0020] Measure and calculate the conversion matrix of the antenna installation coordinate system to the R hole of the unfolding arm R A-R ,X A-R .

[0021] Install a measurement detection mirror at the root of the stretching rod mechanism as a reference for the conversion of the stretching rod mechanism coordinate to the satellite body coordinate system, measure and calculate the conversion matrix of the R hole of the unfolding arm to the newly added cube mirror R R-XZ ,X R-XZ ;

[0022] Take the satellite support vehicle parking surface as the whole satellite reference, the center point coordinate axis origin of the four docking joints, and the upward direction as positive, measure and calculate the conversion matrix of the newly added cube mirror to the whole satellite R XZ-X ,X XZ-X ;

[0023] The antenna coordinate of the stretching pole mechanism is converted into the satellite coordinate system, i.e. the coordinate system is converted from O x1,y1,z1 to O x2,y2,z2 Then, there are:

[0024]

[0025] Wherein, M represents a rotation transformation in the matrix conversion, and an Euler rotation is usually adopted; x0, y0, z0 represent a translation transformation, and M is represented as:

[0026]

[0027] After the antenna position is measured and calculated, the installation precision of the antenna is evaluated, if the installation precision does not meet the requirements, the installation position of the antenna needs to be adjusted, and the precision optimization of the antenna of the stretching pole mechanism is re-performed.

[0028] According to one technical scheme of the present application, in the step S3, the adjusted stretching pole mechanism and all the antenna position coordinate information on the ground plate are bound to the satellite payload direction finding system.

[0029] According to one technical scheme of the present application, in the step S4, the phase difference system error Δφ of the direction finding system, the interferometer baseline length system error Δd, the interferometer azimuth angle system error Δθ, and the interferometer elevation angle system error Δε are estimated by the ground calibration station, and the positioning result is corrected.

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

[0031] The present application actually measures and adjusts the installation precision of the antenna after the antenna is installed, without using the theoretical position coordinate of the antenna installation, greatly reduces the influence of the antenna installation error, and improves the direction finding accuracy of the satellite direction finding system. From the perspective of satellite application and satellite efficiency, the positioning precision of the satellite is greatly improved.

[0032] In the actual measurement process of the antenna position coordinate, the position measurement link is decomposed into the stretching pole mechanism and the ground plate, the precision of the antenna on the installation surface of the stretching pole mechanism, the installation precision of the stretching pole mechanism and the ground plate, and the precision of the antenna on the installation surface of the ground plate are all optimized, and the factors such as structural deformation and tremor that may exist in the satellite development process are considered, so that the cumulative error of the antenna position is reduced.

[0033] When the satellite payload direction finding system is designed, a system error model is established, and the installation error of the antenna can be corrected to a certain extent. When the error exceeds a certain range, the complexity of the correction algorithm is greatly increased, and the processing capacity requirement of the system is sharply improved. After the installation position of the antenna is measured and adjusted, the installation error of the antenna can meet the processing capacity of the algorithm, and the economic cost is effectively saved.

[0034] The method is first proposed and applied in the fixed multi-baseline interferometer direction-finding positioning system, and the application effect has obtained the actual verification of satellite on-orbit application. The method can provide research ideas for subsequent satellites of the same system or the same field. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

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

[0037] Figure 2 The flow chart of the antenna position accuracy optimization according to an embodiment of the present application is shown;

[0038] Figure 3 The schematic diagram of the antenna x-axis installation deviation according to an embodiment of the present application is shown;

[0039] Figure 4 The influence of the antenna x-axis installation deviation according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] As shown in Figure 1 The interferometer antenna position accuracy optimization method of the present application is suitable for the satellite antenna position accuracy optimization of the fixed multi-baseline interferometer direction-finding positioning system. The antennas are in the form of a combination of multiple arrays, and the antennas of different arrays are respectively located on the satellite stretching rod mechanism and the satellite ground plate. The position accuracy optimization is carried out for the antennas in two installation states, so as to fundamentally eliminate the influence of the antenna installation error on the positioning accuracy.

[0042] For satellite antennas mounted on the ground, the sources of positional error include: installation error of the antenna on the mounting surface, installation error between the antenna mounting surface and the satellite body, and deviations caused by satellite vibration and thermal deformation. For antennas on satellite extension mechanisms, the sources of positional error include: installation error of the antenna on the extension mechanism, optimization accuracy of the mechanism, mechanism vibration, and antenna positional deviations caused by thermal deformation.

[0043] The present invention provides a method for optimizing the position accuracy of an interferometer antenna, comprising the following steps:

[0044] Step S1: After checking the antenna's status, install the antenna in place;

[0045] Step S2: Optimize the position accuracy of the antenna according to two states: the ground plane and the extension mechanism, using different methods.

[0046] Step S3: Antenna coordinate position binding;

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

[0048] In some embodiments of the present invention, step S1 involves checking the condition of the antenna to ensure that the antenna surface is intact, without any bumps or scratches, no surface peeling or damage, no extraneous objects, and that the markings are clear, visible, and correct. Otherwise, the antenna needs to be processed before it can be installed.

[0049] The antenna installation position is optimized for both the floor and the extension mechanism, with the optimization process as follows: Figure 2 As shown. Among them, an industrial photogrammetry system was used to take multi-angle photos and multi-view images of the antenna on the floor. Figure Three 3D reconstruction; the antenna on the extension mechanism achieves accuracy optimization through precise measurement and coordinate transformation of both the extension mechanism and the overall satellite structure. In some embodiments of the present invention, in step S2, for the satellite antenna on the ground, industrial photogrammetry is used to optimize its positional accuracy, including:

[0050] (1) After the antenna installation and inspection are in place, industrial photogrammetry is performed on the antennas on the floor. First, circular markers / targets are regularly pasted on the surface of all antennas to evenly cover the antenna surface, which facilitates the full and accurate extraction of image information. Markers are also pasted on the floor surface in the same way. 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 being measured. The reference ruler should be placed at the bottom of the ground antenna array of the object being measured, and the targets at both ends of the reference ruler should not be blocked after placement, so as to provide a length reference for the measurement process.

[0052] (3) Since the shooting image needs to meet the requirements of multi-angle and multi-image, the lifting device is used to collect the shooting image around the satellite, and the lifting device needs to be lifted to the same height as the top antenna and to be freely moved within a certain range from the satellite. The shooting image is checked, and if necessary, the shooting is supplemented to ensure the integrity of the modeling data.

[0053] (4) The shooting image is processed, the reference ruler length information is combined, the measurement data model is established, and the coordinates of the antenna on the floor are calculated. The installation deviation is confirmed by comparing with the theoretical value. If the deviation is large, the antenna position needs to be adjusted.

[0054] (5) After the measurement / adjustment is completed, the antenna and the target on the floor are removed, and it is confirmed again that the antenna and the floor surface are intact without excess. The measurement is completed.

[0055] The process of satellite precision measurement mainly includes establishing mechanical reference and optical reference, and the optical reference is a measurement detection mirror, i.e. a cubic mirror, installed on the whole satellite structure or equipment. In some embodiments of the present application, in the step S2, for the antenna on the stretching rod mechanism, the satellite precision measurement system is combined with the coordinate conversion algorithm, the position coordinates of the antenna on the stretching rod mechanism are converted to the satellite body coordinate system through the measurement detection mirror, R hole and other references, and the installation error is confirmed by comparing with the theoretical design value, including:

[0056] (1) After confirming that the antenna state is correct and installed in place, the precision measurement of the stretching rod mechanism is carried out. The conversion matrix of the antenna installation coordinate system to the R hole of the stretching rod mechanism is measured and calculated, which is represented as: R A-R ,X A- R.

[0057] (2) The measurement detection mirror (new cubic mirror) is installed at the root of the stretching rod mechanism as the reference for converting the stretching rod mechanism coordinate to the satellite body coordinate system. The conversion matrix of the R hole of the stretching rod mechanism to the new cubic mirror is measured and calculated, which is represented as: R R-XZ ,X R-XZ .

[0058] (3) The whole satellite precision measurement is carried out: taking the parking surface of the satellite support vehicle as the whole satellite reference, the center point coordinate axis origin of the four docking joints, and the upward direction as positive, the conversion matrix of the new cubic mirror to the whole satellite is calculated, which is represented as: R XZ-X , X XZ-X .

[0059] (4) Through the conversion matrix calculated in the above steps (1)-(3), the antenna coordinates on the stretching rod mechanism are converted to the satellite body coordinate system by using the rotation and translation transformation of the matrix, i.e. the coordinate system is converted from O x1,y1,z1 to O x2,y2,z2Then there are:

[0060]

[0061] Wherein, M represents the rotation transformation in the matrix conversion, usually using Euler rotation; x0, y0, z0 represent the translation transformation, M represents:

[0062]

[0063] (5), after the completion of the antenna position measurement, the installation precision is evaluated, if the installation precision does not meet the requirements, the installation position of the antenna needs to be adjusted.

[0064] In some embodiments of the application, in the step S3, after the measurement and adjustment of the floor and the antenna of the extension rod mechanism are completed, the coordinates of all antennas are unified to the satellite body coordinate system, and are bound to the satellite payload direction finding system. The error of the interferometer baseline length, the interferometer baseline azimuth angle and the interferometer baseline pitch angle is ensured to be within the index range.

[0065] The specific process can be represented as:

[0066] (1), for the antenna installed on the satellite ground plate, the position coordinates are measured by an industrial photogrammetry system. Regularly paste the mark points (targets) on the surface of the measured antenna, place the reference ruler required for measurement at the bottom end of the antenna array surface, take multiple images at multiple angles, process the image data, determine the actual coordinates of the ground plate antenna, and confirm the installation error;

[0067] (2), for the antenna on the extension rod mechanism, the installation position of the antenna on the extension rod mechanism is measured by a precision measurement system, and the antenna installation coordinates are converted to the extension rod mechanism coordinate system; by measuring different cube mirrors, the antenna coordinates on the extension rod mechanism are converted to the satellite body coordinate system again, and compared with the theoretical design value to confirm the installation error;

[0068] (4), if the error exceeds the threshold value, the position of the antenna needs to be adjusted, and the installation precision is optimized, and the antenna is adjusted to the error index range of the satellite payload direction finding system;

[0069] (5), after the measurement / adjustment of all interferometer antennas is completed, the correct position coordinates are recorded, and the coordinates are bound to the satellite payload direction finding and positioning system, and are used in subsequent direction finding processing. Figure 3 For the schematic diagram of the antenna x-axis installation deviation, Figure 4 The influence of the phase deviation after the antenna x-axis installation deviation. When the antenna installation has deviation, it has a great influence on the phase accuracy of the interferometer, so the installation precision of the antenna needs to be strictly controlled.

[0070] After the satellite is launched, the system error of direction finding positioning may still change due to environmental changes and vibration processes, so on-orbit calibration is needed to correct the direction finding positioning result. Among them, the bias caused by the phase difference system error, the interferometer baseline length system error, the interferometer azimuth angle system error and the interferometer elevation angle system error is usually large.

[0071] In some embodiments of the present application, in the step S4, in order to further improve the positioning accuracy, the factors causing the positioning error are comprehensively considered: the phase difference measurement error, the interferometer baseline length measurement error, the interferometer baseline installation angle error, the observation platform attitude error, the observation platform position error, the frequency measurement error, etc. The error factors with greater influence: 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 are used to establish an error model:

[0072]

[0073] On the ground, a single or multiple calibration stations are established, after the satellite is launched, by using the two priori information of known calibration station position and known signal frequency, through long time observation, the four correction amounts can be estimated, and the direction finding and positioning result in the unknown radiation source position solving process is corrected.

[0074] It should be noted that although the above embodiments of the present application are illustrative, this is not a limitation of the present application, therefore the present application is not limited to the above specific embodiments. Any other embodiments obtained by those skilled in the art under the inspiration of the present application without departing from the principles of the present application are considered to be within the protection scope of the present application.

Claims

1. A method of interferometer antenna position accuracy optimization, characterized by, The method comprises the following steps: S1, after checking the state of the antenna, the antenna is installed in place; S2, the antenna is optimized in position according to two states of the floor and the telescopic rod mechanism by different methods, after the antenna is installed in place, the antenna installed on the floor is measured by industrial photography, comprising: regularly sticking circular mark points / targets on the surface of all antennas; a reference ruler is placed near the measured object according to the requirements of industrial photography, and the reference ruler is placed at the bottom end of the measured floor antenna array surface; photographic images are collected around the satellite by using a lifting device; the photographic images are processed, a measurement data model is established in combination with the length information of the reference ruler, and the coordinates of the antenna on the floor are calculated; it is judged whether the accuracy meets the requirements, if yes, S3 is executed, and if not, the position of the antenna on the floor is adjusted, and the accuracy optimization of the antenna on the floor is performed again; the precision measurement of the telescopic rod mechanism comprises: Measure and calculate the conversion matrix of the antenna installation coordinate system to the spread arm R hole: R A-R , X A-R ; At the root of the extension rod mechanism, a measuring detection mirror is installed as the reference for the conversion of the extension rod mechanism coordinate to the satellite body coordinate system, and the conversion matrix of the extension arm R hole to the newly added cube mirror is measured and calculated: R R-XZ ,X R-XZ ; With the satellite support vehicle parking surface as the whole satellite reference, the center point coordinate axis origin of the four docking joints, and the upward direction as positive, the conversion matrix of the newly added cubic mirror to the whole satellite is measured and calculated: R XZ-X , X XZ-X ; The antenna coordinates of the stick mechanism are converted into the star coordinate system, i.e. the coordinate system is converted from O x1,y1,z1 to O x2,y2,z2 Then, we have: wherein M represents a rotation transformation in matrix conversion, and Euler rotation is usually adopted; x0, y0 and z0 represent translation transformation, and M is represented as: after the position of the antenna is measured, the installation accuracy of the antenna is evaluated, if the installation accuracy does not meet the requirements, the installation position of the antenna needs to be adjusted, and the accuracy optimization of the antenna of the telescopic rod mechanism is performed again; S3, the coordinate position of the antenna is bound; S4, after in-orbit calibration is completed, the influence of the installation error of the antenna on the positioning accuracy is further reduced, and the positioning accuracy is optimized.

2. The interferometer antenna position accuracy optimization method of claim 1, wherein, In the step S1, the state of the antenna is checked to ensure that the surface of the antenna is intact, without scratches, without surface peeling and damage, without redundant objects, and the mark is clear and correct.

3. The interferometer antenna position accuracy optimization method of claim 1, wherein, In the step S3, the adjusted telescopic rod mechanism and the position coordinate information of all antennas on the floor are bound to the satellite payload direction finding system.

4. The interferometer antenna position accuracy optimization method of claim 1, wherein, In the step S4, the phase difference system error Δφ of the direction finding system, the interferometer baseline length system error Δd, the interferometer azimuth angle system error Δθ and the interferometer elevation angle system error Δε are estimated by a ground calibration station, and the positioning result is corrected.

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