High-precision S-curve fitting method and system for integrated search and tracking radar

Abstract

This invention provides a high-precision S-curve fitting method and system for integrated search and track radar, applicable to integrated tracking radar, two-dimensional search radar, or two-dimensional tracking radar. When performing monopulse angle measurement and having limited measured antenna pattern data, an S-curve is generated within the radar's detection range at the azimuth and elevation scanning angles using two-dimensional interpolation. Six elements—beam number, azimuth / elevation dimension, frequency, elevation scanning angle, azimuth scanning angle, difference, and ratio—form a storage address. Angle error data is stored according to agreed-upon addresses, forming a two-dimensional angle error compensation data table. When the target falls within the effective range of the antenna and the main beam of the difference beam, the two-dimensional angle error data is read based on the index address formed by the six elements. The beam center pointing angle is then superimposed with the angle error compensation value to obtain the radar's angle measurement value. When the target deviates significantly from the antenna beam center, error compensation is performed using a lookup table to improve the radar's angle measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing technology, specifically to a high-precision S-curve fitting method and system for integrated search and tracking radar. Background Technology

[0002] Integrated search and track radar not only needs to have the ability to quickly detect different targets, but also needs to have high-precision tracking capabilities. In both cases, high demands are placed on the target detection accuracy of integrated search and track radar. Angular measurement accuracy is a crucial component of target detection accuracy.

[0003] The monopulse angle measurement system can achieve better angle measurement accuracy and has become the angle measurement method commonly used in modern radar. It has also changed from the early pitch monopulse angle measurement and azimuth endpoint estimation method to azimuth and pitch dual-axis monopulse angle measurement.

[0004] In practical applications, in order to reduce the workload of antenna testing and improve the radar debugging progress, the antenna pattern pointing to a limited number of beams is often measured during testing. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-precision S-curve fitting method and system for integrated search and tracking radar.

[0006] In a first aspect, embodiments of this application provide a high-precision S-curve fitting method for integrated search and tracking radar, including:

[0007] Step 1: Draw the elevation S-curve and azimuth S-curve based on the measured antenna pattern. The elevation S-curve is the elevation difference and ratio-angle error curve under each test frequency, test angle and beam number. The azimuth S-curve is the azimuth difference and ratio-angle error curve.

[0008] Step 2: Select the test frequency and beam number, and fix the azimuth test angle as n. i (i=1...n), based on the known S-curve samples corresponding to m pitch test angles, obtain the variation law of the S-curve samples with the pitch scan angle; where n is the number of azimuth test angles and m is the number of pitch test angles;

[0009] Step 3: Based on the variation law of the elevation S-curve samples with elevation angle, select the interpolation method to obtain M elevation S-curves; based on the variation law of the azimuth S-curve samples with elevation angle, select the interpolation method to obtain M azimuth S-curves; where M is the number of elevation scanning angles of the antenna pattern, and should have 5≤m≤M.

[0010] Step 4: Fix the pitch angle to M j(j=1...M), based on the known n azimuth test angles corresponding to the pitch S-curve samples, obtain the variation law of the S-curve samples with the azimuth scan angle;

[0011] Step 5: Based on the variation law of the elevation S-curve samples with azimuth angle, select the interpolation method to obtain N elevation S-curves; based on the variation law of the azimuth S-curve samples with azimuth angle, select the interpolation method to obtain N azimuth S-curves; where N is the number of azimuth scanning angles of the antenna pattern, and should have 5≤n≤N;

[0012] Step 6: Determine if all beam numbers have been traversed. If not, change the beam number and return to Step 2. If yes, determine if all test frequencies have been traversed. If not, change test frequency P. i (i = 1...P) 测试 ), return to step 2, until all test frequencies and beam numbers have obtained M×N elevation S-curves and M×N azimuth S-curves; where P 测试 The number of test frequency points, 3 ≤ P 测试 <P 总 When P 测试 When the frequency is 3, it includes one center frequency, one low frequency, and one high frequency.

[0013] Step 7: Based on the variation of the pitch S-curve sample with the test frequency, select the interpolation method to obtain P. 总 Based on the variation of the azimuth S-curve samples with the test frequency, an interpolation method is selected to obtain P. 总 S-curves in each orientation; where P 总 The number of frequency points used by the radar during operation;

[0014] Step 8: Store all the interpolated curves as a two-dimensional angular error data table according to the preset format.

[0015] Optionally, step 1, which involves plotting the elevation S-curve based on the measured antenna pattern, includes:

[0016] Step A1: Extract antenna pattern data within the range of beam center Δθ for both the pitch and elevation difference patterns;

[0017] Step A2: Calculate the pitch difference pattern and the amplitude ratio of the pattern to obtain the pitch difference and ratio data within approximately Δθ of the beam center;

[0018] Step A3: Establish a coordinate system for pitch difference and S-curve with the scanning angle as the abscissa and pitch difference and ratio as the ordinate, with the beam center as the zero point of the abscissa, and invert the pitch difference and ratio data within 0°.

[0019] Step A4: Extract the difference and ratio within the range of ±r and amplify it by R times, where R is determined by the space of the final storage address. Interpolate the original data using polynomial fitting with an interval of 1 to obtain 2r×R quantized numbers corresponding to the difference and ratio within the range of ±r.

[0020] Step A5: Calculate the angular error with a precision of θ0, and store k signed bits from the storage address, with the stored angular error range being [-θ0×2]. k-1 ,θ0×(2 k-1 -1)], let the part that exceeds the angular error range be equal to the boundary value, and then interchange the horizontal and vertical coordinates so that the horizontal coordinate is the difference and ratio, and the vertical coordinate is the angular error, thus obtaining the pitch S-curve.

[0021] Optionally, step 1, which involves plotting the azimuth S-curve based on the measured antenna pattern, includes:

[0022] Step B1: Extract antenna pattern data within the range of beam center Δθ for the pattern and azimuth difference pattern.

[0023] Step B2: Calculate the amplitude ratio of the azimuth difference pattern to the beam pattern to obtain the azimuth difference and ratio data within approximately Δθ of the beam center;

[0024] Step B3: Establish a coordinate system for directional difference and S-curve with the scanning angle as the abscissa and the directional difference and ratio as the ordinate, making the beam center the zero point of the abscissa, and inverting the directional difference and ratio data within 0°.

[0025] Step B4: Extract the difference and ratio within the ±r range and amplify it by R times, where R is determined by the space of the final storage address. Interpolate the original data using polynomial fitting with an interval of 1 to obtain 2r×R quantized numbers corresponding to the difference and ratio within the ±r range.

[0026] Step B5: Set the quantization precision of the angle error to θ0, and store k signed bits from the storage address, with the stored angle error range being [-θ0×2]. k-1 ,θ0×(2 k-1 -1)], let the part that exceeds the angular error range be equal to the boundary value, and then interchange the horizontal and vertical coordinates so that the horizontal coordinate is the difference and ratio, and the vertical coordinate is the angular error, thus obtaining the azimuth S-curve.

[0027] Optionally, in step 3, based on the variation law of the pitch S-curve samples with pitch angle, an interpolation method is selected to obtain M pitch S-curves, including:

[0028] Select S-curve samples corresponding to m pitch test angles under a fixed azimuth angle;

[0029] Comparing this set of S-curve samples, observe the trend of the angular error values ​​at the same difference and ratio positions with the pitch angle, and select the interpolation method as follows based on the trend:

[0030] If the change of angular error with pitch angle has a clear regularity, then interpolation fitting is performed using polynomial fitting based on the change pattern.

[0031] If the change of angular error with pitch angle does not have a clear regularity, and the angular error values ​​of different pitch test angles, the same difference and ratio are more than 3 quantization units apart, then the interpolation method should be the approximation method. First, determine the median of two adjacent pitch test angles, and make the pitch S-curve corresponding to the pitch angle within the two adjacent medians the same as the pitch S-curve of the known test angles within the range.

[0032] If the change of angular error with pitch angle does not have a clear regularity, and the difference in angular error values ​​under different pitch test angles, the same difference, and the ratio is no more than 3 quantization units, then the interpolation method is to choose the averaging method, that is, to calculate the average angular error under different pitch test angles, the same difference, and the ratio, to form the average pitch S-curve, and make the S-curve of other pitch angles the same as the average pitch S-curve.

[0033] Optionally, in step 3, based on the variation law of the azimuth S-curve samples with elevation angle, an interpolation method is selected to obtain M azimuth S-curves, including:

[0034] Select S-curve samples corresponding to m azimuth test angles under a fixed azimuth angle;

[0035] Comparing this set of S-curve samples, observe the trend of the angular error values ​​at the same difference and ratio positions with the pitch angle, and select the interpolation method as follows based on the trend:

[0036] If the change of angular error with pitch angle has a clear regularity, then interpolation fitting is performed using polynomial fitting based on the change pattern.

[0037] If the change of angular error with pitch angle does not have a clear regularity, and the angular error values ​​of different azimuth test angles, the same difference, and the comparison are greater than 3 quantization units, then the interpolation method should be the approximation method. First, determine the median of two adjacent azimuth test angles, and make the azimuth S-curve corresponding to the pitch angle within the two adjacent medians the same as the azimuth S-curve of the known test angles within the range.

[0038] If the change of angular error with pitch angle does not have a clear regularity, and the difference in angular error values ​​between different azimuth test angles, with the same difference and ratio is no more than 3 quantization units, then the interpolation method is to choose the averaging method, that is, to calculate the average value of angular error under different azimuth test angles, with the same difference and ratio, to form the average azimuth S-curve, and to make the S-curves of other pitch angles the same as the average azimuth S-curve.

[0039] Optionally, the preset format of the two-dimensional angular error data table in step 8 corresponds to the address allocation in the memory, and includes six types of information: beam number, azimuth S-curve (or elevation S-curve), frequency point, elevation scan angle, azimuth scan angle, and difference and ratio.

[0040] Optionally, the data stored in the two-dimensional angle error data table in step 8 are the angle error values ​​corresponding to each difference and ratio.

[0041] Secondly, embodiments of this application provide a high-precision S-curve fitting system for integrated search and tracking radar, comprising: a processor and a memory, wherein the memory stores executable program instructions, and when the processor calls the program instructions in the memory, the processor is used to:

[0042] Perform the steps of the high-precision S-curve fitting method for search and tracking integrated radar as described in any one of the first aspects.

[0043] Thirdly, embodiments of this application provide a computer-readable storage medium for storing a program, which, when executed, implements the steps of the high-precision S-curve fitting method for integrated search and tracking radar as described in any one of the first aspects.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The high-precision S-curve fitting method for integrated search and track radar provided in this application is applicable to two-dimensional search and track radar, and can also be applied to two-dimensional search radar or two-dimensional tracking radar. This method provides angular error compensation data when single-pulse angle measurement is used and the measured antenna pattern data is limited. With a finite number of known measured data points, S-curves are generated for all azimuth and elevation angles through two-dimensional interpolation, producing a two-dimensional angular error data table. This ensures both measurement accuracy and improves work efficiency. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0047] Figure 1 A flowchart illustrating the high-precision S-curve fitting method for integrated search and tracking radar provided in this application embodiment;

[0048] Figure 2(a) shows a known antenna pattern (azimuth) in one embodiment of this application;

[0049] Figure 2(b) is a known antenna pattern (elevation) in one embodiment of this application;

[0050] Figure 3 In one embodiment of this application, the sum and difference radiation patterns near the beam center are extracted;

[0051] Figure 4 This is a schematic diagram of the angle error-difference-ratio curve after the difference and ratio data are reversed in one embodiment of this application;

[0052] Figure 5 This is a schematic diagram of the difference-to-ratio curve of angle error without quantization, which is an amplified difference and ratio curve in one embodiment of this application.

[0053] Figure 6 This is a schematic diagram of the difference and ratio of angle error after angular error quantization and coordinate transformation in one embodiment of this application.

[0054] Figure 7 A flowchart illustrating the selection of interpolation methods provided in this application embodiment;

[0055] Figure 8(a) shows a sample of ΔA / ∑S curves at different elevation angles with a fixed azimuth angle. Figure 1 ;

[0056] Figure 8(b) is a schematic diagram of the ΔA / ∑S curve samples under different pitch angles at a fixed azimuth angle.

[0057] Figure 9(a) shows a sample of ΔE / ∑S curves at different elevation angles with a fixed azimuth angle. Figure 1 ;

[0058] Figure 9(b) is a schematic diagram of the ΔE / ∑S curve samples under different pitch angles at a fixed azimuth angle.

[0059] Figure 10(a) shows a sample of ΔA / ∑S curves at different azimuth angles with a fixed pitch angle. Figure 1 ;

[0060] Figure 10(b) is a schematic diagram of the ΔA / ∑S curve samples under different azimuth angles with a fixed pitch angle.

[0061] Figure 11(a) shows a sample of ΔE / ∑S curves at different azimuth angles with a fixed pitch angle. Figure 1 ;

[0062] Figure 11(b) is a schematic diagram of the ΔE / ∑S curve samples under different azimuth angles with a fixed pitch angle. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0066] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0067] The technical solutions of the present invention and how they solve the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0068] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0069] Figure 1 A flowchart of the high-precision S-curve fitting method for integrated search and tracking radar provided in the embodiments of this application is shown below. Figure 1As shown, the method in this embodiment may include the following steps:

[0070] Step 1: Draw the elevation S-curve and azimuth S-curve based on the measured antenna pattern. The elevation S-curve is the elevation difference and ratio-angle error curve under each test frequency, test angle and beam number. The azimuth S-curve is the azimuth difference and ratio-angle error curve.

[0071] In this embodiment, the elevation S-curve is plotted based on the measured antenna radiation pattern, including:

[0072] Step A1: Extract antenna pattern data within the range of beam center Δθ for both the pitch and elevation difference patterns;

[0073] Step A2: Calculate the pitch difference pattern and the amplitude ratio of the pattern to obtain the pitch difference and ratio data within approximately Δθ of the beam center;

[0074] Step A3: Establish a coordinate system for pitch difference and S-curve with the scanning angle as the abscissa and pitch difference and ratio as the ordinate, with the beam center as the zero point of the abscissa, and invert the pitch difference and ratio data within 0°.

[0075] Step A4: Extract the difference and ratio within the range of ±r and amplify it by R times, where R is determined by the space of the final storage address. Interpolate the original data using polynomial fitting with an interval of 1 to obtain 2r×R quantized numbers corresponding to the difference and ratio within the range of ±r.

[0076] Step A5: Calculate the angular error with a precision of θ0, and store k signed bits from the storage address, with the stored angular error range being [-θ0×2]. k-1 ,θ0×(2 k-1 -1)], let the part that exceeds the angular error range be equal to the boundary value, and then interchange the horizontal and vertical coordinates so that the horizontal coordinate is the difference and ratio, and the vertical coordinate is the angular error, thus obtaining the pitch S-curve.

[0077] In this embodiment, the azimuth S-curve is plotted based on the measured antenna radiation pattern, including:

[0078] Step B1: Extract antenna pattern data within the range of beam center Δθ for the pattern and azimuth difference pattern.

[0079] Step B2: Calculate the amplitude ratio of the azimuth difference pattern to the beam pattern to obtain the azimuth difference and ratio data within approximately Δθ of the beam center;

[0080] Step B3: Establish a coordinate system for directional difference and S-curve with the scanning angle as the abscissa and the directional difference and ratio as the ordinate, making the beam center the zero point of the abscissa, and inverting the directional difference and ratio data within 0°.

[0081] Step B4: Extract the difference and ratio within the ±r range and amplify it by R times, where R is determined by the space of the final storage address. Interpolate the original data using polynomial fitting with an interval of 1 to obtain 2r×R quantized numbers corresponding to the difference and ratio within the ±r range.

[0082] Step B5: Set the quantization precision of the angle error to θ0, and store k signed bits from the storage address, with the stored angle error range being [-θ0×2]. k-1 ,θ0×(2 k-1 -1)], let the part that exceeds the angular error range be equal to the boundary value, and then interchange the horizontal and vertical coordinates so that the horizontal coordinate is the difference and ratio, and the vertical coordinate is the angular error, thus obtaining the azimuth S-curve.

[0083] Step 2: Select the test frequency and beam number, and fix the azimuth test angle as n. i (i=1...n), based on the known S-curve samples corresponding to m pitch test angles, obtain the variation law of the S-curve samples with pitch scan angle.

[0084] Step 3: Based on the variation law of the pitch S-curve samples with pitch angle, select the interpolation method to obtain M pitch S-curves. Based on the variation law of the azimuth S-curve samples with pitch angle, select the interpolation method to obtain M azimuth S-curves.

[0085] In this embodiment, S-curve samples corresponding to m pitch test angles under a fixed azimuth angle are selected; by comparing these S-curve samples, the trend of the angular error value of the same difference and ratio position with the pitch angle is observed, and the interpolation method is selected based on the trend.

[0086] For example, such as Figure 7As shown, comparing the trends of angular error values ​​with pitch angle at the same difference and ratio positions in this set of S-curve samples, the interpolation method is selected based on these trends. The interpolation methods include cubic polynomial fitting, approximation, and averaging: If the angular error shows a clear regularity with the pitch angle, then cubic polynomial fitting is chosen for interpolation, with the pitch test angle as the x-axis and the angular error as the y-axis. Since the difference and ratio have 2048 quantized values, 2048 interpolations are required. If the angular error does not show a clear regularity with the pitch angle, and the angular error values ​​at different pitch test angles and with the same difference and ratio differ by more than 3 quantized units, then the approximation method is chosen for interpolation. First, determine the median of two adjacent pitch test angles, and make the pitch S-curve corresponding to the pitch angle within the two adjacent medians the same as the pitch S-curve of the known test angles within the range; if the angular error does not change with the pitch angle in a clear manner, and the angular error values ​​of different pitch test angles, with the same difference and ratio do not differ by more than 3 quantization units, then the interpolation method is to choose the averaging method, that is, calculate the mean angular error of different pitch test angles, with the same difference and ratio, to form the mean pitch S-curve, and make the S-curve of other pitch angles the same as the mean pitch S-curve.

[0087] For example, taking a low beam azimuth angle of 0° as an example, the ΔA / ∑S curve samples at different elevation angles are shown in Figure 8(a) and Figure 8(b). It can be found that the S curve of ΔA / ∑ does not show a clear regularity with the elevation angle, and the angular error of different elevation angles differs by a maximum of 2 quantization units. Therefore, the averaging method is chosen.

[0088] When the low-beam azimuth angle is 0°, the ΔE / ∑S curve samples at different elevation angles are shown in Figures 9(a) and 9(b). It can be observed that the S curve of ΔE / ∑ changes with the elevation angle in a regular manner; therefore, the cubic polynomial fitting method is selected.

[0089] Step 4: Fix the pitch angle to M j (j=1...M), based on the known n azimuth test angles corresponding to the elevation S-curve samples, obtain the variation law of the S-curve samples with the azimuth scanning angle; where M is the number of elevation scanning angles of the antenna pattern, m is the number of elevation test angles, and 5≤m≤M should be true.

[0090] In this embodiment, taking a low beam elevation angle of 0.85° as an example, the ΔA / ∑S curve samples at different azimuth angles are shown in Figures 10(a) and 10(b). It can be observed that the S curve of ΔA / ∑ exhibits a regularity with the azimuth angle; therefore, cubic polynomial fitting is chosen for interpolation. When the low beam elevation angle is 0.85°, the ΔE / ∑S curve samples at different azimuth angles are shown in Figures 11(a) and 11(b). It can be observed that the S curve of ΔE / ∑ does not exhibit a clear regularity with the azimuth angle, and the angular error values ​​at different azimuth angles differ by up to four quantizations; therefore, an approximation method is chosen for interpolation.

[0091] Step 5: Based on the variation law of the elevation S-curve samples with azimuth angle, select the interpolation method to obtain N elevation S-curves. Based on the variation law of the azimuth S-curve samples with azimuth angle, select the interpolation method to obtain N azimuth S-curves. Wherein, N is the number of azimuth scanning angles of the antenna pattern, n is the number of azimuth test angles, and 5≤n≤N.

[0092] Step 6: Determine if all beam numbers have been traversed. If not, change the beam number and return to Step 2. If yes, determine if all test frequencies have been traversed. If not, change test frequency P. i (i = 1...P) 测试 ), return to step 2, until all test frequencies and beam numbers have obtained M×N elevation S-curves and M×N azimuth S-curves; where P 测试 The number of test frequency points, 3 ≤ P 测试 <P 总 When P 测试 When the frequency is 3, it includes one center frequency, one low frequency, and one high frequency.

[0093] Step 7: Based on the variation of the pitch S-curve sample with the test frequency, select the interpolation method to obtain P. 总 Based on the variation of the azimuth S-curve samples with the test frequency, an interpolation method is selected to obtain P. 总 S-curves in each orientation; where P 总 This refers to the number of frequency points used by the radar during operation.

[0094] In this embodiment, the selection of the interpolation method is described in step 3 above, and will not be repeated here. Specifically, the approximation method is as follows: approximately 15 frequency points above and below the center frequency point are consistent with the S-curve data at the center frequency point; low frequency points outside this range are consistent with the S-curve data at the test low frequency point, and high frequency points are consistent with the S-curve data at the test high frequency point.

[0095] Step 8: Store all the interpolated curves as a two-dimensional angular error data table according to the preset format.

[0096] In this embodiment, the preset format of the two-dimensional angular error data table in step 8 corresponds to the address allocation direction in the memory, and includes six types of information: beam number, azimuth S-curve (or elevation S-curve), frequency point, elevation scan angle, azimuth scan angle, and difference and ratio.

[0097] Examples of two-dimensional data storage formats are shown in Table 1.

[0098] Table 1

[0099]

[0100] The specific explanation is as follows:

[0101] 1) The address consists of 27 bits, represented by D0 to D26 from low to high. Therefore, the highest address formed can be represented as 7ffffff in hexadecimal.

[0102] 2) The highest bit of the address, D26: 1 bit of unsigned binary number, with a value of 0 or 1, representing low beam or high beam respectively;

[0103] 3) D25: A single-bit unsigned binary number, with a value of 0 or 1, representing azimuth or elevation, respectively;

[0104] 4) D24~D22: 3-bit unsigned binary numbers representing frequency points, denoted by FW. The corresponding decimal representation ranges from 0 to 7. Each value represents 8 frequency points, for a total of 0 to 64 frequency points.

[0105] 5) D21~D16: 6-bit signed binary numbers representing the pitch scan angle, denoted by EDEC. The corresponding decimal range is -32 to 31, corresponding to a scan angle range of [-90°, 90°]. That is, -90° to 90° is quantized as [-32:31]. Scan angle quantization precision: 180 / 64 = 2.8125°

[0106] 6) D15~D11: 5-bit signed binary numbers representing the azimuth scan angle, denoted by AMO, with a corresponding decimal range of -16 to 15, and a corresponding scan angle range of [-60°, 60°]. For scan angle quantization precision, see “Azimuth Angle AMO Lookup Table Address Mapping Relationship Table”.

[0107] 7) D10~D0: 11-bit signed binary numbers, represented by D / S, with a decimal range of -1024 to 1023. The range of difference and ratio is [-4,4], which means the difference and ratio are magnified by 256 times.

[0108] For example, the data stored in the two-dimensional angle error data table in step 8 are the angle error values ​​corresponding to each difference and ratio.

[0109] In this embodiment, the stored value is an 8-bit signed angle error value, with a range of -128 to 127. The angle error quantization precision is 360 / 8192 = 0.0439°, and the angle error range is -5.625° to 5811°.

[0110] This embodiment is applicable to two-dimensional search and tracking integrated radar, and can also be applied to two-dimensional search radar or two-dimensional tracking radar. This method provides angular error compensation data when single-pulse angle measurement is used and the measured antenna pattern data is limited. When the measured antenna pattern data for a limited number of azimuth and elevation scan angles is known, the measured data is first converted into an S-curve (the horizontal axis represents the difference and ratio, and the vertical axis represents the angular error). Then, S-curves for the azimuth and elevation scan angles within the radar's detection range are formed using two-dimensional interpolation. Finally, a storage address is formed using six elements: beam number, azimuth / elevation dimension, frequency, elevation scan angle, azimuth scan angle, and difference and ratio. The angular error data is stored according to the agreed address, forming a two-dimensional angular error data table. As long as the target falls within the effective range of the antenna and the main beam of the difference beam, and the radar can detect the target echo normally, the two-dimensional angular error data can be read according to the index address formed by the six elements. The angular error compensation value is then superimposed on the beam center pointing angle to finally obtain the radar's angle measurement value. The high-precision S-curve fitting method can effectively improve the accuracy of angular error data, especially when the target deviates significantly from the beam center. The angular error data can also be accurately found through two-dimensional search, thereby greatly improving the angular measurement accuracy of two-dimensional search and tracking radar.

[0111] It should be noted that those skilled in the art will understand that various aspects of the present invention can be implemented as systems, methods, or program products. Therefore, various aspects of the present invention can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, collectively referred to herein as a "circuit," "module," or "platform."

[0112] Furthermore, embodiments of this application also provide a computer-readable storage medium storing computer-executable instructions. When at least one processor of a user device executes these computer-executable instructions, the user device performs the various possible methods described above. The computer-readable medium includes a computer storage medium and a communication medium, wherein the communication medium includes any medium that facilitates the transfer of a computer program from one location to another. The storage medium can be any available medium accessible to a general-purpose or special-purpose computer. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in the user device. Alternatively, the processor and storage medium can exist as discrete components in a communication device.

[0113] This application also provides a program product including a computer program stored in a readable storage medium. At least one processor of the server can read the computer program from the readable storage medium, and the at least one processor executes the computer program to cause the server to implement any of the methods described in the embodiments of the present invention.

[0114] The program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0115] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A high-precision S-curve fitting method for integrated search and tracking radar, characterized in that, include: Step 1: Draw the elevation S-curve and azimuth S-curve based on the measured antenna pattern. The elevation S-curve is the elevation difference and ratio-angle error curve under each test frequency, test angle and beam number. The azimuth S-curve is the azimuth difference and ratio-angle error curve. Step 2: Select the test frequency and beam number, and fix the azimuth test angle as n. i (i=1...n), based on the known S-curve samples corresponding to m pitch test angles, obtain the variation law of the S-curve samples with the pitch scan angle; where n is the number of azimuth test angles and m is the number of pitch test angles; Step 3: Based on the variation law of the elevation S-curve samples with elevation angle, select the interpolation method to obtain M elevation S-curves; based on the variation law of the azimuth S-curve samples with elevation angle, select the interpolation method to obtain M azimuth S-curves; where M is the number of elevation scanning angles of the antenna pattern, and should have 5≤m≤M. Step 4: Fix the pitch angle to M j (j=1...M), based on the known n azimuth test angles corresponding to the pitch S-curve samples, obtain the variation law of the S-curve samples with the azimuth scan angle; Step 5: Based on the variation law of the elevation S-curve samples with azimuth angle, select the interpolation method to obtain N elevation S-curves; based on the variation law of the azimuth S-curve samples with azimuth angle, select the interpolation method to obtain N azimuth S-curves; where N is the number of azimuth scanning angles of the antenna pattern, and should have 5≤n≤N; Step 6: Determine if all beam numbers have been traversed. If not, change the beam number and return to Step 2. If yes, determine if all test frequencies have been traversed. If not, change test frequency P. i (i = 1...P) 测试 ), return to step 2, until all test frequencies and beam numbers have obtained M×N elevation S-curves and M×N azimuth S-curves; where P 测试 The number of test frequency points, 3 ≤ P 测试 <P 总 When P 测试 When the frequency is 3, it includes one center frequency, one low frequency, and one high frequency. Step 7: Based on the variation of the pitch S-curve sample with the test frequency, select the interpolation method to obtain P. 总 Based on the variation of the azimuth S-curve samples with the test frequency, an interpolation method is selected to obtain P. 总 S-curves in each orientation; where P 总 The number of frequency points used by the radar during operation; Step 8: Store all the interpolated curves as a two-dimensional angular error data table according to the preset format.

2. The high-precision S-curve fitting method for integrated search and tracking radar according to claim 1, characterized in that, Step 1, which involves plotting the elevation S-curve based on the measured antenna pattern, includes: Step A1: Extract antenna pattern data within the range of beam center Δθ for both the pitch and elevation difference patterns; Step A2: Calculate the pitch difference pattern and the amplitude ratio of the pattern to obtain the pitch difference and ratio data within approximately Δθ of the beam center; Step A3: Establish a coordinate system for pitch difference and S-curve with the scanning angle as the abscissa and pitch difference and ratio as the ordinate, with the beam center as the zero point of the abscissa, and invert the pitch difference and ratio data within 0°. Step A4: Extract the difference and ratio within the range of ±r and amplify it by R times, where R is determined by the space of the final storage address. Interpolate the original data using polynomial fitting with an interval of 1 to obtain 2r×R quantized numbers corresponding to the difference and ratio within the range of ±r. Step A5: Calculate the angular error with a precision of θ0, and store k signed bits from the storage address. The stored angular error range is [-θ0×2]. k-1 ,θ0×(2 k-1 -1)], let the part that exceeds the angular error range be equal to the boundary value, and then interchange the horizontal and vertical coordinates so that the horizontal coordinate is the difference and ratio, and the vertical coordinate is the angular error, thus obtaining the pitch S-curve.

3. The high-precision S-curve fitting method for integrated search and tracking radar according to claim 1, characterized in that, Step 1, which involves plotting the azimuth S-curve based on the measured antenna pattern, includes: Step B1: Extract antenna pattern data within the range of beam center Δθ for the pattern and azimuth difference pattern. Step B2: Calculate the amplitude ratio of the azimuth difference pattern to the beam pattern to obtain the azimuth difference and ratio data within approximately Δθ of the beam center; Step B3: Establish a coordinate system for directional difference and S-curve with the scanning angle as the abscissa and the directional difference and ratio as the ordinate, making the beam center the zero point of the abscissa, and inverting the directional difference and ratio data within 0°. Step B4: Extract the difference and ratio within the ±r range and amplify it by R times, where R is determined by the space of the final storage address. Interpolate the original data using polynomial fitting with an interval of 1 to obtain 2r×R quantized numbers corresponding to the difference and ratio within the ±r range. Step B5: Calculate the angular error with a precision of θ0, and store k signed bits from the storage address. The stored angular error range is [-θ0×2]. k-1 ,θ0×(2 k-1 -1)], let the part that exceeds the angular error range be equal to the boundary value, and then interchange the horizontal and vertical coordinates so that the horizontal coordinate is the difference and ratio, and the vertical coordinate is the angular error, thus obtaining the azimuth S-curve.

4. The high-precision S-curve fitting method for integrated search and tracking radar according to claim 1, characterized in that, In step 3, based on the variation law of the pitch S-curve samples with pitch angle, an interpolation method is selected to obtain M pitch S-curves, including: Select S-curve samples corresponding to m pitch test angles under a fixed azimuth angle; Comparing this set of S-curve samples, observe the trend of the angular error values ​​at the same difference and ratio positions with the pitch angle, and select the interpolation method as follows based on the trend: If the change of angular error with pitch angle has a clear regularity, then interpolation fitting is performed using polynomial fitting based on the change pattern. If the change of angular error with pitch angle does not have a clear regularity, and the angular error values ​​of different pitch test angles, the same difference and ratio are more than 3 quantization units apart, then the interpolation method should be the approximation method. First, determine the median of two adjacent pitch test angles, and make the pitch S-curve corresponding to the pitch angle within the two adjacent medians the same as the pitch S-curve of the known test angles within the range. If the change of angular error with pitch angle does not have a clear regularity, and the difference in angular error values ​​under different pitch test angles, the same difference, and the ratio is no more than 3 quantization units, then the interpolation method is to choose the averaging method, that is, to calculate the average angular error under different pitch test angles, the same difference, and the ratio, to form the average pitch S-curve, and make the S-curve of other pitch angles the same as the average pitch S-curve.

5. The high-precision S-curve fitting method for integrated search and tracking radar according to claim 1, characterized in that, In step 3, based on the variation law of the azimuth S-curve samples with elevation angle, an interpolation method is selected to obtain M azimuth S-curves, including: Select S-curve samples corresponding to m azimuth test angles under a fixed azimuth angle; Comparing this set of S-curve samples, observe the trend of the angular error values ​​at the same difference and ratio positions with the pitch angle, and select the interpolation method as follows based on the trend: If the change of angular error with pitch angle has a clear regularity, then interpolation fitting is performed using polynomial fitting based on the change pattern. If the change of angular error with pitch angle does not have a clear regularity, and the angular error values ​​of different azimuth test angles, the same difference, and the comparison are greater than 3 quantization units, then the interpolation method should be the approximation method. First, determine the median of two adjacent azimuth test angles, and make the azimuth S-curve corresponding to the pitch angle within the two adjacent medians the same as the azimuth S-curve of the known test angles within the range. If the change of angular error with pitch angle does not have a clear regularity, and the difference in angular error values ​​between different azimuth test angles, with the same difference and ratio is no more than 3 quantization units, then the interpolation method is to choose the averaging method, that is, to calculate the average value of angular error under different azimuth test angles, with the same difference and ratio, to form the average azimuth S-curve, and to make the S-curves of other pitch angles the same as the average azimuth S-curve.

6. The high-precision S-curve fitting method for search and track integrated radar according to any one of claims 1-5, characterized in that, In step 8, the preset format of the two-dimensional angular error data table corresponds to the address allocation in the memory, and includes six types of information: beam number, azimuth S-curve or elevation S-curve, frequency point, elevation scan angle, azimuth scan angle, and difference and ratio.

7. The high-precision S-curve fitting method for search and track integrated radar according to any one of claims 1-5, characterized in that, The data stored in the two-dimensional angle error data table in step 8 are the angle error values ​​corresponding to each difference and ratio.

8. A high-precision S-curve fitting system for integrated search and tracking radar, characterized in that, include: A processor and a memory, wherein the memory stores executable program instructions, and when the processor invokes the program instructions in the memory, the processor is used to: The steps of performing the high-precision S-curve fitting method for integrated search and tracking radar as described in any one of claims 1 to 7.

9. A computer-readable storage medium for storing a program, characterized in that, When the program is executed, it implements the steps of the high-precision S-curve fitting method for integrated search and tracking radar as described in any one of claims 1 to 7.

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