Two-dimensional image inverse-diffraction RCS acquisition method and related device based on direction correction

Abstract

The present invention relates to the field of radio measurement, and specifically to a two-dimensional image back-derivation RCS acquisition method based on direction correction and a related device; the present invention comprises: acquiring a target echo signal and a calibration body echo signal; performing a two-dimensional imaging algorithm on the target echo signal and the calibration body echo signal to obtain a compensation matrix group; performing directional pattern correction on the target two-dimensional image and the calibration body two-dimensional image based on the compensation matrix group, respectively, obtaining a target two-dimensional image group and a calibration body two-dimensional image group and performing back-derivation to obtain a transformation ratio matrix; and obtaining the RCS result of the target according to the transformation ratio matrix. The present invention combines multiple size parameters to accurately calculate the number of resolution units of the two-dimensional image, effectively avoiding the problem of resource waste caused by too many units in the traditional method, optimizing the calculation efficiency and resource utilization of the system, and at the same time, the accurate unit number calculation also provides a more reliable data basis for subsequent imaging processing, ensuring the efficiency and accuracy of the imaging process.

Description

Technical Field

[0001] The invention relates to the field of radio measurement, and in particular to a two-dimensional image anti-diffraction RCS acquisition method based on direction correction and a related device. Background Art

[0002] Radar Cross Section (RCS) is an important parameter to measure the target's ability to scatter radar waves. It is widely used in target identification, stealth technology, radar system design and other fields. RCS testing is to analyze the scattering characteristics of the target by transmitting electromagnetic waves through the radar system and receiving the echo signal reflected by the target. The traditional RCS test method usually relies on omnidirectional antennas and finally obtains the RCS value of the target by algorithmically processing the target echo signal.

[0003] The traditional RCS test method is often used as a two-dimensional image anti-derivation algorithm. The steps of this algorithm include: obtaining two-dimensional images of each from the target echo and the calibration body echo, and performing inverse two-dimensional discrete Fourier transform on each of the two-dimensional images, and then dividing the inverse two-dimensional discrete Fourier transform result corresponding to the target by the inverse two-dimensional discrete Fourier transform result corresponding to the calibration body to obtain a ratio result, and performing two-dimensional interpolation on the ratio result according to frequency and angle to finally obtain the RCS corresponding to the target.

[0004] The traditional RCS test method has the following problems in practical applications: 1. The traditional method usually requires the use of omnidirectional antennas to ensure that the target's echo signal can be evenly received at different angles. However, omnidirectional antennas are prone to introduce unnecessary interference in practical applications, such as multipath effects, environmental clutter, etc. These interferences will seriously affect the accuracy of RCS testing; if omnidirectional antennas are not used, although interference can be reduced to a certain extent, the target's echo power will fluctuate with the change of the antenna radiation pattern. The power attenuation caused by the radiation pattern will introduce additional errors, making the RCS value obtained by the traditional method inaccurate. Summary of the invention

[0005] In view of the problems mentioned in the prior art, the present invention proposes a two-dimensional image anti-diffraction RCS acquisition method and related devices based on direction correction, which can reduce interference while avoiding the power attenuation problem caused by the directional pattern, thereby improving the accuracy and reliability of RCS testing.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for acquiring RCS of a two-dimensional image based on direction correction, comprising the following steps:

[0008] Acquire target echo signal and calibration body echo signal;

[0009] Perform a two-dimensional imaging algorithm on the target echo signal and the calibration body echo signal to obtain a two-dimensional image of the target and a two-dimensional image of the calibration body;

[0010] A compensation matrix group is obtained according to the target two-dimensional image and the calibration body two-dimensional image;

[0011] Based on the compensation matrix group, the directional images of the target two-dimensional image and the calibration body two-dimensional image are respectively corrected to obtain a target two-dimensional image group and a calibration body two-dimensional image group;

[0012] Perform inverse derivative on the target two-dimensional image group and the calibration volume two-dimensional image group to obtain the transformation ratio matrix;

[0013] The RCS result of the target is obtained according to the transformation ratio matrix.

[0014] As a further improvement of the present invention, the target echo signal is , the calibration body echo signal is ;

[0015]

[0016] Where: Indicates rotation angle, ; represents the starting angle; Indicates the rotation angle step; Indicates the number of sweep angles of the echo;

[0017]

[0018] Where: represents the kth step frequency, ; represents the initial frequency; Indicates frequency step; Indicates the number of echo step frequency points.

[0019] As a further improvement of the present invention, the two-dimensional imaging algorithm for the target echo signal and the calibration body echo signal includes:

[0020] The target echo signal and the calibration body echo signal are calibrated by distance respectively, and the calibration results of the target echo signal and the calibration body echo signal are obtained. The expressions are as follows:

[0021]

[0022] Where: Indicates the calibration result of the target echo signal; Indicates the calibration result of the calibration body echo signal; represents a natural constant; Indicates the target echo signal; Indicates the calibration body echo signal; Indicates the distance between the radar antenna and the target's rotation center; represents the speed of light; represents an imaginary unit; represents the kth step frequency, ;

[0023] The calibration results of the target echo signal and the calibration body echo signal are subjected to inverse discrete Fourier transform to obtain the one-dimensional radial range image of the target at different scanning angles and the one-dimensional radial range image of the positioning body at different scanning angles. The expressions are as follows:

[0024]

[0025] Where: Represents the one-dimensional radial range image of the target at different scanning angles, where ; Represents the one-dimensional radial range image of the positioning body at different scanning angles, where ; represents the number of discrete Fourier transform points, and , Indicates the number of step frequency points of the echo; represents the inverse discrete Fourier transform;

[0026] The one-dimensional radial range images of the target at different scanning angles and the one-dimensional radial range images of the positioning body at different scanning angles are reversely projected and interpolated. First, the number of horizontal and vertical resolution units is obtained by combining the two-dimensional image size, the number of scanning points and the frequency step. The calculation formula is as follows:

[0027]

[0028] Where: Indicates the number of horizontal and vertical resolution units; Indicates the size of a two-dimensional image in meters; Indicates the number of step frequency points of the echo; Indicates frequency step; represents the initial frequency; represents the speed of light;

[0029] The reverse projection surface is obtained according to the number of horizontal and vertical resolution units. The calculation formula of the reverse projection surface is as follows:

[0030]

[0031] Where: Indicates rotation angle, ; , Represents the matrix element index of the two-dimensional image; Represents the discrete value of the horizontal coordinate of a two-dimensional image; Represents the discrete value of the vertical coordinate of a two-dimensional image; represents the back-projection surface; Indicates the distance between the radar antenna and the target's rotation center;

[0032]

[0033]

[0034] According to the reverse projection surface, the resolution unit under the corresponding scanning angle is obtained, and the calculation formula is as follows:

[0035]

[0036] Where: represents the back-projection surface; Indicates the maximum unambiguous distance; Indicates Resolution units under scanning angles; Indicates the number of discrete Fourier transform points;

[0037]

[0038] Where: represents the speed of light; Indicates frequency step;

[0039] According to the resolution unit under the corresponding scanning angle, the resolution unit difference is obtained, and the calculation formula is as follows:

[0040]

[0041] Where: Indicates the resolution unit difference; Express Round down;

[0042] According to the resolution unit under the corresponding scanning angle, the integer quantization resolution unit is obtained, and the calculation formula is as follows:

[0043]

[0044] Where: Indicates Integer quantization resolution unit corresponding to the scanning angle;

[0045] Inserting integer quantized resolution units and resolution unit differences into one-dimensional radial range images of the target at different scanning angles and one-dimensional radial range images of the positioning body at different scanning angles to obtain a two-dimensional image of the target and a two-dimensional image of the positioning body, respectively;

[0046] The target two-dimensional image expression is as follows:

[0047]

[0048] Where: Represents the target two-dimensional image; Indicates the number of sweep angles of the echo; Indicates Under the sweep angle, The radial distance one-dimensional image value of the target corresponding to the index; Indicates Under the sweep angle, The radial distance one-dimensional image value of the target corresponding to the index;

[0049] The expression of the two-dimensional image of the positioning volume is as follows:

[0050]

[0051] Where: Represents a two-dimensional image of a positioning body; Indicates Under the sweep angle, The one-dimensional image value of the radial distance of the calibration volume corresponding to the index; Indicates Under the sweep angle, The one-dimensional image value of the radial distance of the calibration volume corresponding to the index.

[0052] As a further improvement of the present invention, the process of obtaining the compensation matrix group includes:

[0053] Get the two-dimensional image angle matrix, the calculation formula is as follows:

[0054]

[0055] Where: Represents the two-dimensional image angle matrix; Indicates the distance between the radar antenna and the target's rotation center; Represents the discrete value of the horizontal coordinate of a two-dimensional image; Represents the discrete value of the vertical coordinate of a two-dimensional image; represents the inverse tangent function;

[0056] According to the two-dimensional image angle matrix combined with the two-way pattern function of the antenna, the compensation matrix group is obtained, and the expression is as follows:

[0057]

[0058] Where: represents the compensation matrix group; represents the two-way pattern function of the antenna; Indicates the selected frequency;

[0059]

[0060] Where: represents the selected frequency group index, is a constant; Indicates frequency step; represents the initial frequency; Indicates the number of echo step frequency points.

[0061] As a further improvement of the present invention, the target two-dimensional image group The definition is as follows:

[0062]

[0063] Calibration Volume 2D Image Set The definition is as follows:

[0064]

[0065] Where: represents the compensation matrix group; Represents the target two-dimensional image; Represents the two-dimensional image of the positioning body.

[0066] As a further improvement of the present invention, the process of obtaining the transformation ratio matrix includes:

[0067] For each selected frequency group index The corresponding target two-dimensional image group and calibration volume two-dimensional image group are respectively subjected to two-dimensional discrete Fourier transform to obtain the target two-dimensional image group result And the calibration volume 2D image group results ,in Indicates the horizontal axis index; Indicates the vertical axis index;

[0068] Compare the target 2D image group result with the calibration volume 2D image group result to get the transformation ratio matrix, which is expressed as follows:

[0069]

[0070] Where: Represents the transformation ratio matrix.

[0071] As a further improvement of the present invention, the process of obtaining the target RCS result includes:

[0072] Calculate the frequency matrix as follows:

[0073]

[0074] Where: represents the frequency matrix; Indicates the number of discrete Fourier transform points; Indicates frequency step; represents the initial frequency; Indicates the horizontal axis index; Indicates the vertical axis index; Indicates the number of sweep angles of the echo;

[0075] Combine the frequency matrix with the transformation ratio matrix if ,in, Indicates the horizontal axis index that meets the conditions. Take 1 to ; Indicates the vertical axis index that meets the conditions. Take 1 to , is a constant;

[0076]

[0077] Where: represents the integration matrix; Indicates that at a specific index , The integration matrix Corresponding element value;

[0078] right Perform two-dimensional interpolation on the rotation angle and step frequency to obtain the ratio of the target echo to the calibration volume echo under far-field conditions. ;

[0079] The resulting RCS expression of the target is:

[0080]

[0081] Where: It represents the theoretical RCS result of the calibration body; Indicates the RCS result of the target.

[0082] In a second aspect, the present invention proposes a two-dimensional image anti-diffraction RCS acquisition system based on direction correction, comprising:

[0083] A first acquisition module is used to acquire a target echo signal and a calibration body echo signal;

[0084] The first imaging module is used to perform a two-dimensional imaging algorithm on the target echo signal and the calibration body echo signal to obtain a two-dimensional image of the target and a two-dimensional image of the calibration body;

[0085] A second acquisition module is used to obtain a compensation matrix group according to the target two-dimensional image and the calibration body two-dimensional image;

[0086] The second imaging module is used to perform directional image correction on the target two-dimensional image and the calibration body two-dimensional image respectively based on the compensation matrix group to obtain a target two-dimensional image group and a calibration body two-dimensional image group;

[0087] The anti-derivation module is used to perform anti-derivation on the target two-dimensional image group and the calibration volume two-dimensional image group to obtain a transformation ratio matrix;

[0088] The generation module is used to obtain the RCS result of the target according to the transformation ratio matrix.

[0089] In a third aspect, the present invention proposes a two-dimensional image inverse derivative RCS acquisition device based on direction correction, comprising a processor and a memory, wherein the processor implements the two-dimensional image inverse derivative RCS acquisition method based on direction correction as described above when executing a computer program stored in the memory.

[0090] In a fourth aspect, the present invention proposes a computer-readable storage medium for storing a computer program, wherein the computer program, when executed by a processor, implements the two-dimensional image inverse-derivative RCS acquisition method based on direction correction as described above.

[0091] Compared with the prior art, the present invention has achieved the following technical effects:

[0092] The present invention corrects the directional patterns of the target two-dimensional image and the calibration body two-dimensional image through a compensation matrix group, effectively eliminating the power attenuation error caused by the directional pattern of the non-omnidirectional antenna, while avoiding the multipath effect and environmental clutter interference introduced by the omnidirectional antenna, thereby improving the accuracy and reliability of the RCS test.

[0093] The present invention can accurately calculate the number of two-dimensional image resolution units by combining parameters such as frequency step, initial frequency, number of frequency steps and two-dimensional image size. Compared with the traditional method, when calculating the number of two-dimensional image resolution units, a fixed calculation mode is usually adopted, which will cause the calculation result to not match the actual demand, and often produce too many two-dimensional image resolution units, which not only increases the calculation complexity of the system, but also causes waste of storage resources and computing resources. The present invention effectively avoids the resource waste problem caused by too many two-dimensional image resolution units in the traditional method, optimizes the calculation efficiency and resource utilization of the system, and at the same time, the accurate calculation of the number of two-dimensional image resolution units also provides a more reliable data basis for subsequent imaging processing, ensuring the efficiency and accuracy of the imaging process.

[0094] The present invention performs pattern correction based on the position of each pixel point in the two-dimensional image in combination with the pattern, and performs compensation processing on each pixel point. Compared with the traditional method in which the target echo power is attenuated as the antenna pattern changes, the present invention can effectively offset the echo power attenuation caused by the angle deviation, thereby significantly improving the imaging quality and accuracy of the two-dimensional image, which not only improves the uniformity of the imaging, but also ensures the accuracy and reliability of the imaging results, providing an important basis for subsequent applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 It is a schematic diagram of the process of the present invention;

[0096] Figure 2 The target scattering point distribution diagram simulated by the present invention;

[0097] Figure 3 A three-dimensional stereogram of a two-way pattern function of an antenna generated for an embodiment of the present invention;

[0098] Figure 4 A front view of a two-way pattern function of an antenna generated for an embodiment of the present invention;

[0099] Figure 5 A schematic diagram of a two-dimensional image of the object of the present invention;

[0100] Figure 6 A schematic diagram of a two-dimensional image of a calibration body according to the present invention;

[0101] Figure 7 It is the scanning angle error between the target RCS result obtained by the traditional method and the true RCS result;

[0102] Figure 8 The invention obtains the scanning angle error between the target RCS result and the actual RCS result. DETAILED DESCRIPTION

[0103] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0104] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments:

[0105] like Figure 1The figure shows a flow chart of the present invention. The present invention proposes a two-dimensional image anti-diffraction RCS acquisition method based on direction correction, which performs two-dimensional imaging on the received target echo and calibration body echo; calculates the two-dimensional image angle matrix for the actual position corresponding to each pixel value of the two-dimensional image, selects a frequency group, and then calculates each frequency of the selected frequency group according to the two-way directional pattern function combined with the two-dimensional image angle matrix to obtain a compensation matrix group. The compensation matrix group is used to correct the directional pattern of the two-dimensional image.

[0106] Perform 2D discrete Fourier transform on the target 2D image group and calibration volume 2D image group of the selected frequency group index to obtain the target 2D image group results and calibration volume 2D image group results, compare the target 2D image group results and calibration volume 2D image group results to obtain the transformation ratio matrix. Calculate the frequency matrix, combine the frequency matrix with the transformation ratio matrix, obtain the corresponding element values ​​of the integration matrix according to the horizontal axis index and vertical axis index that meet the conditions, perform 2D interpolation on the corresponding element values ​​of the integration matrix with respect to the rotation angle and the step frequency, obtain the target echo and calibration volume echo ratio, and calculate the target RCS result according to the target echo and calibration volume echo ratio and the calibration volume RCS result.

[0107] This embodiment is simulated under Matlab 2007 to implement the method proposed in this embodiment.

[0108] like Figure 2 The distribution position of the target scattering points of the present invention is shown. The coordinates of six scattering points are set at the center of the target, namely (1,0), (0,1), (-1,0), (0,-1), (0.5,0), (-0.4,0.4), and the scattering value is set to 0.05; the target diameter is set to , the distance between the radar antenna and the target's rotation center , in meters. The scattering value of the calibration volume is set to 0.05.

[0109] Starting angle , Rotation angle stepping , initial frequency , frequency step , the number of echo sweep angles , the number of echo step frequency points , , represents the selected frequency group index;

[0110] Generate target echo signal according to the above parameter values Calibration volume echo signal as follows:

[0111]

[0112]

[0113] Where: Indicates the target index; Represents the two-way direction function graph of the antenna, such as Figure 3 and Figure 4 shown.

[0114]

[0115] According to the position coordinates of different scattering points , and the jth corner Calculate the target deflection angle , the expression is as follows:

[0116]

[0117] The theoretical RCS result of the calibration body is obtained by calculating the target deflection angle , the expression is as follows:

[0118]

[0119] The real far-field target echo is calculated based on the above parameters and the true far-field calibration volume echo , defined as follows:

[0120]

[0121]

[0122] Based on the real far-field target echo and the true far-field calibration volume echo , calculate the actual RCS result , the calculation formula is:

[0123]

[0124] Where: Indicates the real RCS result; It represents the theoretical RCS result of the calibration body.

[0125] The process of the two-dimensional image anti-diffraction RCS acquisition method based on direction correction of the present invention is as follows:

[0126] Step 1: In this embodiment, substitute the above values ​​to calculate the rotation angle and step frequency , the calculation formula is as follows:

[0127]

[0128]

[0129] Calculate the target echo signal as , the calibration body echo signal is , the results are as follows:

[0130] It is expressed as follows:

[0131]

[0132] It is expressed as follows:

[0133]

[0134] Step 2: Calculate the target two-dimensional image based on the above parameters 2D image of the calibration volume , respectively expressed as follows:

[0135] It is expressed as:

[0136]

[0137] It is expressed as:

[0138]

[0139] like Figure 5 and Figure 6 As shown, there are the two-dimensional image of the target and the two-dimensional image of the calibration body of the present invention.

[0140] Step 3: Calculate the compensation matrix group , which is expressed as follows:

[0141] when hour, It is expressed as:

[0142]

[0143] when hour, It is expressed as:

[0144]

[0145] …

[0146] when hour, It is expressed as:

[0147]

[0148] Step 4: Use the compensation matrix group to correct the directional pattern of the two-dimensional image to obtain the compensated target two-dimensional image group , calibration volume 2D image set , which is expressed as follows:

[0149] It is expressed as:

[0150]

[0151] It is expressed as:

[0152]

[0153] …

[0154] It is expressed as:

[0155]

[0156] It is expressed as:

[0157]

[0158] It is expressed as:

[0159]

[0160] …

[0161] It is expressed as:

[0162]

[0163] Step 5: Derivatively perform the target 2D image group and the calibration volume 2D image group in step 4 to obtain the transformation ratio matrix .

[0164] when hour, It is expressed as:

[0165]

[0166] when hour, It is expressed as:

[0167]

[0168] …

[0169] when hour, It is expressed as:

[0170]

[0171] Step 6: Get the RCS result of the target , which is expressed as follows:

[0172]

[0173] In this embodiment, the RCS value of the target calculated is Calculate the scanning angle error as follows:

[0174] The actual RCS result obtained by the above calculation Substitute into it:

[0175]

[0176] Get the scanning angle error for:

[0177]

[0178] like Figure 7 and Figure 8 As shown, Figure 7 is the scanning angle error between the target RCS result obtained by the traditional method and the true RCS result, Figure 8 The scanning angle error between the target RCS result obtained by the present invention and the real RCS result is shown in the comparison. Figure 7 The scanning angle error is greater than Figure 8 The smaller the scanning angle error, the more accurate the RCS result is. Therefore, compared with the traditional method, the present invention corrects the directional pattern of the target two-dimensional image and the calibration body two-dimensional image through a compensation matrix group, thereby improving the accuracy and reliability of the RCS test.

[0179] Based on the same inventive concept, an embodiment of the present invention further provides a two-dimensional image anti-diffraction RCS acquisition system based on direction correction. Since the principle of solving the problem by the two-dimensional image anti-diffraction RCS acquisition system based on direction correction is similar to the aforementioned two-dimensional image anti-diffraction RCS acquisition method based on direction correction, the implementation of the two-dimensional image anti-diffraction RCS acquisition system based on direction correction can refer to the implementation of the two-dimensional image anti-diffraction RCS acquisition method based on direction correction, and the repeated parts will not be repeated.

[0180] In a specific implementation, the two-dimensional image anti-diffraction RCS acquisition system based on direction correction provided by an embodiment of the present invention specifically includes:

[0181] A first acquisition module is used to acquire a target echo signal and a calibration body echo signal;

[0182] The first imaging module is used to perform a two-dimensional imaging algorithm on the target echo signal and the calibration body echo signal to obtain a two-dimensional image of the target and a two-dimensional image of the calibration body;

[0183] A second acquisition module is used to obtain a compensation matrix group according to the target two-dimensional image and the calibration body two-dimensional image;

[0184] The second imaging module is used to perform directional image correction on the target two-dimensional image and the calibration body two-dimensional image respectively based on the compensation matrix group to obtain a target two-dimensional image group and a calibration body two-dimensional image group;

[0185] The anti-derivation module is used to perform anti-derivation on the target two-dimensional image group and the calibration volume two-dimensional image group to obtain a transformation ratio matrix;

[0186] The generation module is used to obtain the RCS result of the target according to the transformation ratio matrix.

[0187] Correspondingly, an embodiment of the present invention further provides a two-dimensional image inverse-derivative RCS acquisition device based on direction correction, comprising a processor and a memory, wherein the processor implements the two-dimensional image inverse-derivative RCS acquisition method based on direction correction provided in an embodiment of the present invention when executing a computer program stored in the memory.

[0188] For more specific processes of the above method, please refer to the corresponding contents disclosed in the aforementioned embodiments, which will not be repeated here.

[0189] Correspondingly, an embodiment of the present invention further provides a computer-readable storage medium for storing a computer program, wherein when the computer program is executed by a processor, the two-dimensional image inverse-derivative RCS acquisition method based on direction correction as provided in an embodiment of the present invention is implemented.

[0190] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the systems, devices, and storage media disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0191] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0192] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0193] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0194] The above is a detailed introduction to the two-dimensional image anti-diffraction RCS acquisition method based on direction correction and related devices provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A two-dimensional image inverse derivative RCS acquisition method based on direction correction, characterized in that: The following steps are involved: Acquire target echo signal and calibration body echo signal; Perform a two-dimensional imaging algorithm on the target echo signal and the calibration body echo signal to obtain a two-dimensional image of the target and a two-dimensional image of the calibration body; A compensation matrix group is obtained according to the target two-dimensional image and the calibration body two-dimensional image; Based on the compensation matrix group, the directional images of the target two-dimensional image and the calibration body two-dimensional image are respectively corrected to obtain a target two-dimensional image group and a calibration body two-dimensional image group; Perform inverse derivative on the target two-dimensional image group and the calibration volume two-dimensional image group to obtain the transformation ratio matrix; The RCS result of the target is obtained according to the transformation ratio matrix.

2. The method for acquiring RCS of two-dimensional image based on direction correction according to claim 1, characterized in that: The target echo signal is , the calibration body echo signal is ; Where: Indicates rotation angle, ; represents the starting angle; Indicates the rotation angle step; Indicates the number of sweep angles of the echo; Where: represents the kth step frequency, ; represents the initial frequency; Indicates frequency step; Indicates the number of echo step frequency points.

3. The method for acquiring RCS of two-dimensional image based on direction correction according to claim 1, characterized in that: The two-dimensional imaging algorithm for the target echo signal and the calibration body echo signal includes: The target echo signal and the calibration body echo signal are calibrated by distance respectively, and the calibration results of the target echo signal and the calibration body echo signal are obtained. The expressions are as follows: Where: Indicates the calibration result of the target echo signal; Indicates the calibration result of the calibration body echo signal; represents a natural constant; Indicates the target echo signal; Indicates the calibration body echo signal; Indicates the distance between the radar antenna and the target's rotation center; represents the speed of light; represents an imaginary unit; represents the kth step frequency, ; The calibration results of the target echo signal and the calibration body echo signal are subjected to inverse discrete Fourier transform to obtain the one-dimensional radial range image of the target at different scanning angles and the one-dimensional radial range image of the calibration body at different scanning angles. The expressions are as follows: Where: Represents the one-dimensional radial range image of the target at different scanning angles, where ; represents the one-dimensional radial range image of the calibration body at different scanning angles, where ; represents the number of discrete Fourier transform points, and , Indicates the number of step frequency points of the echo; represents the inverse discrete Fourier transform; The one-dimensional radial range images of the target at different scanning angles and the one-dimensional radial range images of the calibration volume are reversely projected and interpolated. First, the number of horizontal and vertical resolution units is obtained by combining the two-dimensional image size, the number of scanning points and the frequency step. The calculation formula is as follows: Where: Indicates the number of horizontal and vertical resolution units; Indicates the size of a two-dimensional image in meters; Indicates the number of step frequency points of the echo; Indicates frequency step; represents the initial frequency; represents the speed of light; The reverse projection surface is obtained according to the number of resolution units in the horizontal and vertical directions. The calculation formula of the reverse projection surface is as follows: Where: Indicates rotation angle, ; , Represents the matrix element index of the two-dimensional image; Represents the discrete value of the horizontal coordinate of a two-dimensional image; Represents the discrete value of the vertical coordinate of a two-dimensional image; represents the back-projection surface; Indicates the distance between the radar antenna and the target's rotation center; According to the reverse projection surface, the resolution unit under the corresponding scanning angle is obtained, and the calculation formula is as follows: Where: represents the back-projection surface; Indicates the maximum unambiguous distance; Indicates Resolution units under scanning angles; Indicates the number of discrete Fourier transform points; Where: represents the speed of light; Indicates frequency step; According to the resolution unit under the corresponding scanning angle, the resolution unit difference is obtained, and the calculation formula is as follows: Where: Indicates the resolution unit difference; Express Round down; According to the resolution unit under the corresponding scanning angle, the integer quantization resolution unit is obtained, and the calculation formula is as follows: Where: Indicates Integer quantization resolution unit corresponding to the scanning angle; Inserting integer quantization resolution units and resolution unit differences into one-dimensional radial range images of the target at different scanning angles and one-dimensional radial range images of the calibration body at different scanning angles to obtain a two-dimensional image of the target and a two-dimensional image of the calibration body respectively; The target two-dimensional image expression is as follows: Where: Represents the target two-dimensional image; Indicates the number of sweep angles of the echo; Indicates Under the sweep angle, The radial distance one-dimensional image value of the target corresponding to the index; Indicates Under the sweep angle, The radial distance one-dimensional image value of the target corresponding to the index; The expression of the two-dimensional image of the calibration volume is as follows: Where: represents the two-dimensional image of the calibration volume; Indicates Under the sweep angle, The one-dimensional image value of the radial distance of the calibration volume corresponding to the index; Indicates Under the sweep angle, The one-dimensional image value of the radial distance of the calibration volume corresponding to the index.

4. The method for acquiring RCS of two-dimensional image based on direction correction according to claim 1, characterized in that: The process of obtaining the compensation matrix group includes: Get the two-dimensional image angle matrix, the calculation formula is as follows: Where: Represents the two-dimensional image angle matrix; Indicates the distance between the radar antenna and the target's rotation center; Represents the discrete value of the horizontal coordinate of a two-dimensional image; Represents the discrete value of the vertical coordinate of a two-dimensional image; represents the inverse tangent function; According to the two-dimensional image angle matrix combined with the two-way pattern function of the antenna, the compensation matrix group is obtained, and the expression is as follows: Where: represents the compensation matrix group; represents the two-way pattern function of the antenna; Indicates the selected frequency; Where: represents the selected frequency group index, is a constant; Indicates frequency step; represents the initial frequency; Indicates the number of echo step frequency points.

5. The method for acquiring RCS of two-dimensional image based on direction correction according to claim 4, characterized in that: Target 2D image group The definition is as follows: Calibration Volume 2D Image Group The definition is as follows: Where: represents the compensation matrix group; Represents the target two-dimensional image; Represents the two-dimensional image of the calibration volume.

6. The method for acquiring RCS of two-dimensional image based on direction correction according to claim 5, characterized in that: The process of obtaining the transformation ratio matrix includes: For each selected frequency group index The corresponding target two-dimensional image group and calibration volume two-dimensional image group are respectively subjected to two-dimensional discrete Fourier transform to obtain the target two-dimensional image group result And the calibration volume 2D image group results ,in Indicates the horizontal axis index; Indicates the vertical axis index; Compare the target 2D image group result with the calibration volume 2D image group result to get the transformation ratio matrix, which is expressed as follows: Where: Represents the transformation ratio matrix.

7. The method for acquiring RCS of two-dimensional image based on direction correction according to claim 6, characterized in that: The process of obtaining the target's RCS result includes: Calculate the frequency matrix as follows: Where: represents the frequency matrix; Indicates the number of discrete Fourier transform points; Indicates frequency step; represents the initial frequency; Indicates the horizontal axis index; Indicates the vertical axis index; Indicates the number of sweep angles of the echo; Combine the frequency matrix with the transformation ratio matrix if ,in, Indicates the horizontal axis index that meets the conditions. Take 1 to ; Indicates the vertical axis index that meets the conditions. Take 1 to , is a constant; Where: represents the integration matrix; Indicates that at a specific index , The integration matrix Corresponding element value; right Perform two-dimensional interpolation on the rotation angle and step frequency to obtain the ratio of the target echo to the calibration volume echo under far-field conditions. ; The resulting RCS expression of the target is: Where: It represents the theoretical RCS result of the calibration body; Indicates the RCS result of the target.

8. A two-dimensional image anti-diffraction RCS acquisition system based on direction correction, characterized in that: include: A first acquisition module is used to acquire a target echo signal and a calibration body echo signal; The first imaging module is used to perform a two-dimensional imaging algorithm on the target echo signal and the calibration body echo signal to obtain a two-dimensional image of the target and a two-dimensional image of the calibration body; A second acquisition module is used to obtain a compensation matrix group according to the target two-dimensional image and the calibration body two-dimensional image; The second imaging module is used to perform directional image correction on the target two-dimensional image and the calibration body two-dimensional image respectively based on the compensation matrix group to obtain a target two-dimensional image group and a calibration body two-dimensional image group; The anti-derivation module is used to perform anti-derivation on the target two-dimensional image group and the calibration volume two-dimensional image group to obtain a transformation ratio matrix; The generation module is used to obtain the RCS result of the target according to the transformation ratio matrix.

9. A two-dimensional image anti-diffraction RCS acquisition device based on direction correction, characterized in that: The method comprises a processor and a memory, wherein the processor implements the two-dimensional image inverse derivative RCS acquisition method based on direction correction as described in any one of claims 1 to 7 when executing the computer program stored in the memory.

10. A computer-readable storage medium, characterized in that: Used to store a computer program, wherein when the computer program is executed by a processor, the two-dimensional image inverse derivative RCS acquisition method based on direction correction as described in any one of claims 1 to 7 is implemented.

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