Swing arm type spherical near field point-by-point dynamic high-order probe compensation method and system

Abstract

The invention discloses a swing arm type spherical near field point-by-point dynamic high-order probe compensation method and system, and belongs to the technical field of antenna testing. Aiming at the defect that only one-dimensional mechanical errors can be processed in the prior art, non-ideal radius and angular deviation caused by the two-dimensional offset are dynamically calculated for each sampling point by obtaining the two-dimensional offset between a measurement coordinate system and a measured antenna coordinate system, and the non-ideal radius and angular deviation are converted into Euler rotation angles; the dynamic parameters are fused into a calculation model of a probe response constant, and the model comprises translation and rotation effects of spherical waves at the same time; and finally, reconstructing and solving an antenna transmission equation by using a dynamic response constant, and directly outputting a high-precision far-field pattern. According to the method, the nonlinear coupling probe positioning error caused by the two-dimensional mechanical error can be effectively compensated, the test precision and the system robustness are improved, additional calibration steps are not needed, the efficiency is high, and the practicability is high.

Description

Technical Field

[0001] This invention belongs to the field of antenna testing and measurement technology, specifically relating to a method and system for compensating a swing-arm spherical near-field point-by-point dynamic high-order probe based on Euler rotation and translation. Background Technology

[0002] With the rapid development of 6G communication, satellite internet, and millimeter-wave / terahertz technology, the demand for performance testing of high-frequency antennas and large-scale array antennas has increased dramatically. Spherical near-field testing technology, due to its high precision and full-space scanning capability, has become a core method for antenna pattern and gain measurement. However, in actual testing, the measurement coordinate system and the coordinate system of the antenna under test are often offset due to mechanical assembly errors, leading to probe positioning errors and spherical distortion, which in turn introduces pattern testing errors.

[0003] The closest existing technical solution: Existing calibration techniques constrain mechanical errors to the X-axis dimension. Figure 1 This example demonstrates measuring a spherical coordinate system. Relative to the coordinate system of the antenna under test There is an offset The probe's pointing orientation must be determined by angle through coordinate system offset. Calibration is performed to align it with the coordinate system of the antenna under test. Additionally, further translation operations are needed on the probe's mode coefficients to compensate for non-ideal radii. The influence of this. Typically, the probe position can be obtained based on known or calculated measurement geometry. For Figure 1 The offset measurement scenario shown has a non-ideal radius. and angle deviation It can be calculated using the following formula: ; ; The position of the probe in the measurement coordinate system is known to be... Based on this model, the corresponding Euler rotation angle can be used. This is used to correct the orientation of the probe relative to the coordinate system of the antenna under test.

[0004] The probe response constant also needs to be calculated point-by-point, based on each sampling point. Perform separate calculations: ; in, Represents the translation of a spherical wave. Partially representing the rotation of spherical waves, Let be the receiving coefficient of the probe. Substituting the above equation into the antenna transmission equation and converting it into a matrix-vector representation, the resulting linear equations can be used to calculate the antenna transmission coefficient and ultimately obtain the far-field radiation pattern of the antenna under test.

[0005] Disadvantages of existing technology: Traditional compensation algorithms only constrain mechanical errors in the X-axis dimension and do not consider the Y-axis dimension. They cannot effectively handle nonlinear dynamic coupling probe errors caused by two-dimensional mechanical errors, making it difficult for existing technologies to meet the requirements of high-precision antenna testing. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the shortcomings of the one-dimensional mechanical error compensation model in the existing spherical near-field measurement technology, and to provide a method and system for point-by-point dynamic high-order probe compensation based on Euler rotation and translation for swing arm type spherical near-field measurement, which can effectively handle two-dimensional mechanical offset and achieve high-precision and high-efficiency probe error compensation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A probe error compensation method for near-field measurement using a swing-arm spherical surface includes the following steps: S1. Obtain measurement condition parameters: Obtain the two-dimensional mechanical offset between the measurement spherical coordinate system and the coordinate system of the antenna under test. ; S2. Calculate probe pose error: For each sampling point Based on two-dimensional mechanical offset And the ideal position of the probe in the measurement coordinate system, calculate the actual non-ideal radius of the probe at that sampling point. and the angular deviation relative to the ideal pointing direction and ; S3. Determine coordinate transformation parameters: based on angle deviation. and Determine the Euler rotation angle used to describe the rotational transformation between the ideal probe coordinate system and the non-ideal probe coordinate system. ; S4. Calculate the dynamic probe response: for each sampling point Based on non-ideal radius Euler rotation angle Calculate the dynamic probe response constant at this point. ; S5. Reconstruct and solve the transmission equation: Substitute the dynamic probe response constant of each sampling point into the antenna transmission equation, construct a matrix form of equations and solve them to obtain the compensated antenna transmission coefficient, and then calculate the far-field radiation pattern of the antenna under test.

[0008] Preferably, in step S2, the ideal position of the probe in the measurement coordinate system is determined. Non-ideal radius and angle deviation , Calculated using the following formula: ; ; ; in, The ideal pitch angle of the probe in the measurement coordinate system.

[0009] Preferably, in step S4, the dynamic probe response constant The calculation formula is: in, Indicates the operating wave number. Indicates the actual test radius. This indicates the calibration Euler rotation angle used to align the probe with the coordinate system of the antenna under test. This represents the translation coefficient of a spherical wave. The rotation factor representing a spherical wave, This indicates the receiver coefficient of the probe. The spherical wave index of the antenna under test. For the spherical wave index of the probe, This represents the radial function of the inner or outer traveling wave.

[0010] Preferably, two-dimensional mechanical offset The value is either fixed or changes dynamically during the measurement process; Euler rotation angle. Calculated dynamically based on the location of each sampling point.

[0011] Preferably, this method can handle non-uniformly distributed sampling point data caused by compensating for two-dimensional mechanical offsets, without relying on a regular sampling grid.

[0012] Furthermore, the present invention also mentions a probe error compensation system for implementing any of the methods described above, the system comprising: The parameter input module is configured to input the two-dimensional mechanical offset between the measurement spherical coordinate system and the coordinate system of the antenna under test. The error calculation module is configured to calculate the non-ideal radius and angle deviation for each sampling point based on the offset and the ideal position of the probe. The transformation parameter module is configured to determine the Euler rotation angle of each sampling point based on the angular deviation; The response calculation module is configured to calculate the dynamic probe response constant at each sampling point based on the non-ideal radius and Euler rotation angle. The equation solving and far-field calculation module is configured to reconstruct and solve the antenna transmission equation using the dynamic probe response constant, and then calculate the compensated antenna far-field pattern.

[0013] The beneficial technical effects of this invention are as follows: High-precision compensation: By establishing a precise mathematical model between two-dimensional mechanical offset and probe pose error, it is possible to handle nonlinear dynamic coupling errors that cannot be solved by one-dimensional models, and significantly improve the testing accuracy under non-ideal assembly conditions.

[0014] Strong algorithm compatibility: The compensation mechanism of this method is implemented at the algorithm level, which can directly process the non-uniform sampling data formed after compensation. It breaks through the dependence of traditional algorithms on regular sampling grids and enhances the robustness and scene adaptability of the test system.

[0015] High testing efficiency: The error compensation process is embedded into the core algorithm of near-field and far-field transformation, realizing an integrated process of "measurement-compensation-transformation", avoiding additional and time-consuming independent calibration steps (such as using a laser tracker), thereby reducing testing complexity and time cost.

[0016] Wide applicability: This method does not rely on specific high-cost auxiliary measurement equipment and can be implemented in existing pendulum spherical near-field systems through software algorithm upgrades, making it easy to promote and apply. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the testing conditions for one-dimensional mechanical error (Δx only) in the prior art. Figure 2 Two-dimensional mechanical error in the embodiments of the present invention A diagram illustrating the test conditions. Figure 3 This is a flowchart of the point-by-point dynamic high-order probe compensation method based on Euler rotation and translation proposed in this invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: This embodiment applies to a typical swing-arm spherical near-field antenna measurement system. The system consists of a precision turntable, an arc-shaped swing arm, a probe antenna mounted at the end of the swing arm, a vector network analyzer, and a control and data processing computer.

[0019] Step S1: Obtain measurement condition parameters; Before testing or during the test setup phase, the measurement spherical coordinate system is determined using engineering drawings, installation measurements, or system self-calibration procedures. Coordinate system with the antenna under test The relative offset within the horizontal plane.

[0020] Step S2: Calculate the probe pose error (combined with...) Figure 2 illustrate); The measurement system controls the probe to sample on the theoretical sphere. For each sampling point... Given that its ideal position coordinates in the measurement coordinate system are... The corresponding ideal pitch angle is Based on the two-dimensional offset Calculate the actual probe pose parameters at this point: Non-ideal radius : The actual distance from the probe to the origin of the coordinate system of the antenna under test.

[0021] ; Pitch angle deviation The change in the actual pitch angle of the probe relative to its ideal direction.

[0022] ; Azimuth deviation In the horizontal plane, the change in the azimuth angle between the actual pointing direction of the probe and its ideal pointing direction.

[0023] ; These calculations are performed in real time at each sampling point, therefore , , It changes dynamically depending on the location of the sampling point.

[0024] Step S3: Determine the coordinate transformation parameters; To mathematically describe the rotation of the probe coordinate system due to pose error, the angular deviation ( , Transformed into a set of Euler rotation angles The order of Euler angles can be determined according to the specific geometric conventions used for measurement.

[0025] Step S4: Calculate the dynamic probe response; Probe response constant It serves as a bridge connecting the mode coefficients of the antenna under test and the signal received by the probe. In this invention, its calculation takes into account non-ideal radius and Euler rotation: in, Indicates the operating wave number. Indicates the actual test radius. This indicates the calibration Euler rotation angle used to align the probe with the coordinate system of the antenna under test. This represents the translation coefficient of a spherical wave. The rotation factor representing a spherical wave, This indicates the receiver coefficient of the probe. The spherical wave index of the antenna under test. For the spherical wave index of the probe, This represents the radial function of the inner or outer traveling wave.

[0026] Step S5: Reconstruct and solve the transmission equations; Substitute the dynamic probe response constants at each sampling point into the antenna transmission equation, construct a matrix-form set of equations and solve them to obtain the compensated antenna transmission coefficients, and then calculate the far-field radiation pattern of the antenna under test.

[0027] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A probe error compensation method in near-field measurement of a swing-arm spherical surface, characterized in that, Includes the following steps: S1. Obtain measurement condition parameters: Obtain the two-dimensional mechanical offset between the measurement spherical coordinate system and the coordinate system of the antenna under test. ; S2. Calculate probe pose error: For each sampling point Based on two-dimensional mechanical offset And the ideal position of the probe in the measurement coordinate system, calculate the actual non-ideal radius of the probe at that sampling point. and the angular deviation relative to the ideal pointing direction and ; S3. Determine coordinate transformation parameters: based on angle deviation. and Determine the Euler rotation angle used to describe the rotational transformation between the ideal probe coordinate system and the non-ideal probe coordinate system. ; S4. Calculate the dynamic probe response: for each sampling point Based on non-ideal radius Euler rotation angle Calculate the dynamic probe response constant at this point. ; S5. Reconstruct and solve the transmission equation: Substitute the dynamic probe response constant of each sampling point into the antenna transmission equation, construct a matrix form of equations and solve them to obtain the compensated antenna transmission coefficient, and then calculate the far-field radiation pattern of the antenna under test.

2. The probe error compensation method in near-field measurement of a swing-arm spherical surface according to claim 1, characterized in that, In step S2, the ideal position of the probe in the measurement coordinate system is determined. Non-ideal radius and angle deviation , Calculated using the following formula: ； ； ； in, The ideal pitch angle of the probe in the measurement coordinate system.

3. The probe error compensation method in near-field measurement of a swing-arm spherical surface according to claim 1, characterized in that, In step S4, the dynamic probe response constant The calculation formula is: in, Indicates the operating wave number. Indicates the actual test radius. This indicates the calibration Euler rotation angle used to align the probe with the coordinate system of the antenna under test. This represents the translation coefficient of a spherical wave. The rotation factor representing a spherical wave. This indicates the receiver coefficient of the probe. The spherical wave index of the antenna under test. For the spherical wave index of the probe, This represents the radial function of the inner or outer traveling wave.

4. The probe error compensation method in near-field measurement of a swing-arm spherical surface according to claim 1, characterized in that, Two-dimensional mechanical offset The value is either fixed or changes dynamically during the measurement process; Euler rotation angle. Calculated dynamically based on the location of each sampling point.

5. The probe error compensation method in near-field measurement of a swing-arm spherical surface according to claim 1, characterized in that, This method can handle non-uniformly distributed sampling point data caused by compensating for two-dimensional mechanical offsets, without relying on a regular sampling grid.

6. A probe error compensation system for implementing the method according to any one of claims 1 to 5, characterized in that, The system includes: The parameter input module is configured to input the two-dimensional mechanical offset between the measurement spherical coordinate system and the coordinate system of the antenna under test. The error calculation module is configured to calculate the non-ideal radius and angle deviation for each sampling point based on the offset and the ideal position of the probe. The transformation parameter module is configured to determine the Euler rotation angle of each sampling point based on the angular deviation; The response calculation module is configured to calculate the dynamic probe response constant at each sampling point based on the non-ideal radius and Euler rotation angle. The equation solving and far-field calculation module is configured to reconstruct and solve the antenna transmission equation using the dynamic probe response constant, and then calculate the compensated antenna far-field pattern.

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