Improved near far field data transformation method and apparatus based on transfer matrix

Abstract

The application discloses an improved near-far field data conversion method and device based on a transfer matrix, and belongs to the field of RCS testing and data processing. The method comprises the following steps: according to the maximum size of a target to be measured on a rotating plane and the distance from the center of a measuring antenna to the scattering center of the target, a synthetic aperture angle required for conversion calculation is calculated; a one-dimensional grid division processing is performed on the region where the target to be measured is located along the transverse direction, and a near-field test observation matrix and a far-field test observation matrix of the target to be measured are respectively established in the grid region obtained through the division; according to the near-field test observation matrix and the far-field test observation matrix, a transfer matrix used for converting near-field scattering characteristic data into far-field scattering characteristic data is calculated; and the transfer matrix is updated according to a preset test frequency and a conversion processing center angle, so that all far-field scattering characteristic data of the target to be measured is calculated. The application can effectively reduce the size of an observation matrix and improve the calculation efficiency.

Description

Technical Field

[0001] This invention relates to the field of RCS testing and data processing technology, and in particular to an improved near-field and far-field data transformation method and apparatus based on transfer matrix. Background Technology

[0002] The definition of a target's RCS (Radar Cross Section) is a far-field concept, requiring that both the incident wave illuminating the target and the scattered wave reaching the receiving antenna be plane waves. However, a truly ideal plane wave does not exist. In engineering, outdoor RCS testing generally adopts a far-field approach, where the distance between the target and the measurement system is sufficiently large, and the incident and scattered waves approximate plane waves. Indoor testing utilizes equipment such as parabolic reflectors to convert the spherical waves radiated by the feed source into plane waves within a certain area. When testing conditions are limited and approximate plane waves cannot be achieved, researchers employ a near-far-field transformation measurement method to extract the far-field scattering information of the target from the near-field scattered echo, thereby obtaining the RCS.

[0003] In related technologies, near-field and far-field transformations are usually performed using methods based on antenna coupling formulas or the invariance of the target scattering distribution function. However, when dealing with large targets and high test frequencies, the size of the observation matrix increases dramatically, leading to problems such as low computational efficiency and slow computation speed.

[0004] Therefore, there is an urgent need for an improved near-field and far-field data transformation method and apparatus based on the transfer matrix to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides an improved near-field and far-field data transformation method and apparatus based on the transfer matrix, which can solve the problems of large observation matrix size and low computational efficiency in related technologies. The technical solution is as follows:

[0006] On the one hand, an improved near-field and far-field data transformation method based on the transfer matrix is ​​provided, the method comprising:

[0007] Based on the maximum size of the target under test on the plane of rotation and the distance from the center of the measuring antenna to the target scattering center, the synthetic aperture angle required for the transformation calculation is calculated.

[0008] The area where the target is located is divided into one-dimensional grids along the horizontal direction, and near-field test observation matrices and far-field test observation matrices of the target are established in the divided grid areas respectively; wherein, the value range of the transformation processing center angle is determined according to the synthetic aperture angle required for the transformation calculation;

[0009] Based on the near-field test observation matrix and the far-field test observation matrix, a transfer matrix for converting near-field scattering characteristic data into far-field scattering characteristic data is calculated.

[0010] The transfer matrix is ​​updated according to the preset test frequency and the transformation processing center angle to calculate all the far-field scattering characteristic data of the target under test.

[0011] On the other hand, an improved near-field and far-field data transformation apparatus based on a transfer matrix is ​​provided, the apparatus comprising:

[0012] The first calculation module is used to calculate the synthetic aperture angle required for the transformation calculation based on the maximum size of the target under test on the rotation plane and the distance from the center of the measuring antenna to the target scattering center.

[0013] The modeling module is used to perform one-dimensional gridding of the area where the target is located along the horizontal direction, and to establish near-field test observation matrix and far-field test observation matrix of the target in the gridded area respectively; wherein, the value range of the transformation processing center angle is determined according to the synthetic aperture angle required for the transformation calculation;

[0014] The second calculation module is used to calculate, based on the near-field test observation matrix and the far-field test observation matrix, a transfer matrix for converting near-field scattering characteristic data into far-field scattering characteristic data.

[0015] The third calculation module is used to update the transfer matrix according to the preset test frequency and the transformation processing center angle, and calculate all the far-field scattering characteristic data of the target under test.

[0016] On the other hand, a computer device is provided, the computer device including a memory and a processor, the memory for storing a computer program, and the processor for executing the computer program stored in the memory to implement the steps of the improved near-field and far-field data transformation method based on the transfer matrix described above.

[0017] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored therein, and when executed by a processor, the computer program implements the steps of the improved near-field and far-field data transformation method based on the transfer matrix described above.

[0018] On the other hand, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the improved near-field and far-field data transformation method based on the transfer matrix described above.

[0019] The technical solution provided by this invention can bring at least the following beneficial effects: First, based on the maximum linear dimension of the target and the antenna-to-target distance, the synthetic aperture angle required for the transformation calculation is determined, and the target is processed into a one-dimensional grid along the lateral direction; then, a near-field observation matrix is ​​constructed to realize the mapping from scattering characteristics to the scattering center; a far-field observation matrix is ​​constructed to realize the mapping from the target's scattering center to the frequency domain far-field scattering characteristics; finally, a transfer matrix is ​​constructed to realize the mapping from the target's frequency domain near-field scattering characteristics to the RCS. This method, by optimizing the target, greatly reduces the size of the near-field and far-field observation matrices, thereby improving the efficiency and speed of near-field and far-field transformation calculations for large-size target data. Attached Figure Description

[0020] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of an improved near-field and far-field data transformation method based on a transfer matrix provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram illustrating the data change effects obtained by different methods according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram illustrating the data change effect before and after the improvement based on the transfer matrix, according to an embodiment of the present invention.

[0024] Figure 4 This is a structural diagram of an improved near-field and far-field data transformation device based on a transfer matrix provided in an embodiment of the present invention;

[0025] Figure 5 This is a hardware architecture diagram of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] As mentioned earlier, when the target size is large and the testing frequency is high, the size of the observation matrix will increase dramatically in the existing technology, resulting in problems such as low computational efficiency and slow computation speed.

[0028] Based on this, the concept of the present invention is to improve computational efficiency and reduce computation time by reducing the size of the constructed observation matrix.

[0029] The following describes the specific implementation of the above concept.

[0030] Please refer to Figure 1 This invention provides an improved near-field and far-field data transformation method based on a transfer matrix, the method comprising:

[0031] Step 100: Calculate the synthetic aperture angle required for the transformation calculation based on the maximum size of the target under test on the rotation plane and the distance from the center of the measuring antenna to the target scattering center.

[0032] Step 102: Divide the area where the target is located into a one-dimensional grid along the horizontal direction, and establish the near-field test observation matrix and far-field test observation matrix of the target in the grid area respectively; wherein, the value range of the transformation processing center angle is determined according to the synthetic aperture angle required for the transformation calculation.

[0033] Step 104: Based on the near-field test observation matrix and the far-field test observation matrix, calculate the transfer matrix used to convert near-field scattering characteristic data into far-field scattering characteristic data;

[0034] Step 106: Update the transfer matrix according to the preset test frequency and the transformation processing center angle, and calculate all the far-field scattering characteristic data of the target under test.

[0035] In this embodiment of the invention, the synthetic aperture angle required for the transformation calculation is first determined based on the target's maximum linear dimensions and the antenna-to-target distance, and the target is then subjected to one-dimensional meshing along the lateral direction. Next, a near-field observation matrix is ​​constructed to map the scattering characteristics to the scattering center; a far-field observation matrix is ​​constructed to map the target's scattering center to its frequency-domain far-field scattering characteristics; finally, a transfer matrix is ​​constructed to map the target's frequency-domain near-field scattering characteristics to its RCS. This method optimizes the target, significantly reducing the size of the near-field and far-field observation matrices, thereby improving the efficiency and speed of near-field and far-field transformation calculations for large-size target data.

[0036] The following description Figure 1 The execution method for each step is shown.

[0037] First, for step 100, the synthetic aperture angle required for the transformation calculation is calculated based on the maximum size of the target under test on the rotation plane and the distance from the center of the measuring antenna to the target scattering center.

[0038] In this embodiment of the invention, the synthetic aperture angle required for the transformation calculation is calculated using the following formula:

[0039]

[0040] in, Θ The required synthetic aperture angle for transformation calculation; D To measure the distance from the antenna center to the target scattering center; R This represents the maximum size of the target object on the plane of rotation.

[0041] For the above formula Θ min Meaning: To obtain the target at a specific angle θ For far-field scattering data of 0, when performing near-field to far-field transformation, the angular range of the near-field data processed must include [ θ 0 -Θ min / 2 , θ 0 +Θ min / 2 Otherwise, the near-field and far-field transformation results will have a large error.

[0042] Then, for step 102, the area where the target to be tested is located is divided into one-dimensional grids along the horizontal direction, and the near-field test observation matrix and far-field test observation matrix of the target to be tested are established in the grid area respectively.

[0043] In this embodiment of the invention, the mesh generation process is centered on the target rotation center and divided into sections with a horizontal length of... D The area is divided into regions at equal intervals. N x Grid points, N x The following requirements should be met:

[0044]

[0045] in, f max The highest frequency of test data, Δφ This indicates the angular interval corresponding to the near-field data. c 0 represents the speed of light in a vacuum.

[0046] In this embodiment of the invention, near-field test observation matrices and far-field test observation matrices of the target to be tested are established within the divided grid regions, including:

[0047] Based on the selected test frequency and transformation processing center angle, a near-field test observation matrix is ​​established to convert the target's scattering center distribution into complex scattering data measured in the near field.

[0048] Based on the preset reconstruction angle range and reconstruction angle sequence, a far-field test observation matrix is ​​established to convert the target's scattering center distribution into standard far-field RCS data.

[0049] Specifically, the near-field test observation matrix is ​​established using the following formula:

[0050]

[0051] In the formula, f p For testing frequency; θ q To change the center angle; a m,n The element in the m-th row and n-th column of the near-field test observation matrix; R m,n The distance from the nth grid point to the center of the measuring antenna at the mth target rotation angle is given by the center of the measuring antenna as the origin of the coordinate system. θ m Indicated by θ q Centered on Θ Within the range of m One angle; x n Represents the first [unit] within the divided grid region. n The coordinates of each grid point.

[0052] The far-field test observation matrix is ​​established using the following formula:

[0053]

[0054] in, b k,j The far-field test observation matrix is ​​the first k line, number j Column elements; R k,j To reconstruct the angle range with the target's rotation center as the origin. Inner k From the perspective of individual target reconstruction Next j The distance between each grid point and the origin; x j For the first grid region obtained by divisionj The coordinates of each grid point.

[0055] To ensure reconstruction accuracy, the reconstruction angle range The following conditions must be met:

[0056] .

[0057] For step 104, based on the near-field test observation matrix and the far-field test observation matrix, a transfer matrix is ​​calculated to convert near-field scattering characteristic data into far-field scattering characteristic data.

[0058] In this embodiment of the invention, the transfer matrix T K×M This can be established using the following formula:

[0059]

[0060] in express The Hermitian matrix.

[0061] For step 106, the transfer matrix is ​​updated according to the preset test frequency and the transformation processing center angle to calculate all the far-field scattering characteristic data of the target under test.

[0062] In this embodiment of the invention, far-field data is calculated:

[0063]

[0064] express f p , Θ q Corresponding target near-field scattering characteristics data; express f p , The corresponding transformed target far-field scattering characteristics data.

[0065] Next, change θ q Take values ​​up to the frequency. f p The far-field scattering characteristics data for all corresponding angular domains have been calculated; change f p The values ​​are taken until the far-field scattering characteristics data for all frequencies have been calculated.

[0066] like Figure 2As shown, the near-field scattering calculation data (blue curve), far-field theoretical data (black curve), and the improved far-field transformation calculation data (red curve) proposed in this embodiment are compared, demonstrating that the method proposed in this embodiment has higher near-field and far-field transformation accuracy.

[0067] like Figure 3 As shown, the near-field and far-field transformation method based on the transfer matrix... Figure Two The extrapolation results of near-field calculation data of a certain model are compared. The blue curve represents the original method, and the red curve represents the method of this embodiment. This shows that the improved method has the same calculation accuracy as the original method.

[0068] Please refer to Figure 4 This invention provides an improved near-field and far-field data transformation device based on a transfer matrix, the device comprising:

[0069] The first calculation module is used to calculate the synthetic aperture angle required for the transformation calculation based on the maximum size of the target under test on the rotation plane and the distance from the center of the measuring antenna to the target scattering center.

[0070] The modeling module is used to perform one-dimensional gridding of the area where the target is located along the horizontal direction, and to establish near-field test observation matrix and far-field test observation matrix of the target in the gridded area respectively; wherein, the value range of the transformation processing center angle is determined according to the synthetic aperture angle required for the transformation calculation;

[0071] The second calculation module is used to calculate, based on the near-field test observation matrix and the far-field test observation matrix, a transfer matrix for converting near-field scattering characteristic data into far-field scattering characteristic data.

[0072] The third calculation module is used to update the transfer matrix according to the preset test frequency and the transformation processing center angle, and calculate all the far-field scattering characteristic data of the target under test.

[0073] In this embodiment of the invention, the synthetic aperture angle required for the transformation calculation is calculated using the following formula:

[0074]

[0075] in, Θ The required synthetic aperture angle for transformation calculation; D To measure the distance from the antenna center to the target scattering center; R This represents the maximum size of the target object on the plane of rotation.

[0076] In this embodiment of the invention, establishing near-field and far-field test observation matrices for the target under test within the divided grid regions includes:

[0077] Based on the selected test frequency and transformation processing center angle, a near-field test observation matrix is ​​established to convert the target's scattering center distribution into complex scattering data measured in the near field.

[0078] Based on the preset reconstruction angle range and reconstruction angle sequence, a far-field test observation matrix is ​​established to convert the target's scattering center distribution into standard far-field RCS data.

[0079] In this embodiment of the invention, the near-field test observation matrix is ​​established using the following formula:

[0080]

[0081] In the formula, f p For testing frequency; θ q To change the center angle; a m,n The element in the m-th row and n-th column of the near-field test observation matrix; R m,n The distance from the nth grid point to the center of the measuring antenna at the mth target rotation angle is given by the center of the measuring antenna as the origin of the coordinate system. θ m Indicated by θ q Centered on Θ Within the range of m One angle; x n Represents the first [unit] within the divided grid region. n The coordinates of each grid point.

[0082] In this embodiment of the invention, the far-field test observation matrix is ​​established using the following formula:

[0083]

[0084] in, b k,j The far-field test observation matrix is ​​the first k line, number j Column elements; R k,j To reconstruct the angle range with the target's rotation center as the origin. Inner k From the perspective of individual target reconstruction Next j The distance between each grid point and the origin; x j For the first grid region obtained by division j The coordinates of each grid point.

[0085] In this embodiment of the invention, the transfer matrix T K×M It is calculated using the following formula:

[0086]

[0087] in, A M×N This is the near-field test observation matrix; B K×N This is the far-field test observation matrix.

[0088] It should be noted that the improved near-field and far-field data transformation device based on the transfer matrix provided in the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the improved near-field and far-field data transformation device based on the transfer matrix provided in the above embodiments and the improved near-field and far-field data transformation method embodiments based on the transfer matrix belong to the same concept. The specific implementation process is detailed in the method embodiments and will not be repeated here.

[0089] Embodiments of this application also provide a computer device, please refer to... Figure 5 The computer device includes a processor and a memory, the memory storing at least one instruction, at least one program, code set, or instruction set, the at least one instruction, at least one program, code set, or instruction set being loaded and executed by the processor to implement the improved near-field and far-field data transformation method based on the transfer matrix provided in the above-described method embodiments.

[0090] Embodiments of this application also provide a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, at least one program, code set, or instruction set is loaded and executed by a processor to implement the improved near-field and far-field data transformation method based on the transfer matrix provided in the above-described method embodiments.

[0091] Embodiments of this application also provide a computer program product comprising a computer program, wherein a processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, causing the computer device to perform any of the improved near-field and far-field data transformation methods based on transfer matrices described in the above embodiments.

[0092] For ease of description, the above systems or devices are described separately as various modules or units based on their functions. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware components.

[0093] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0094] Finally, it should be noted that in this document, relational terms such as first, second, third, and fourth are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0095] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. An improved near-field and far-field data transformation method based on a transfer matrix, characterized in that, The method includes: Based on the maximum size of the target under test in the plane of rotation and the distance from the center of the measuring antenna to the target scattering center, the synthetic aperture angle required for the transformation calculation is calculated. The synthetic aperture angle required for the transformation calculation is obtained by the following formula: in, Θ The required synthetic aperture angle for transformation calculation; D To measure the distance from the antenna center to the target scattering center; R The maximum dimension of the target object on the plane of rotation; The area where the target is located is divided into one-dimensional grids along the horizontal direction, and near-field test observation matrices and far-field test observation matrices of the target are established in the divided grid areas respectively; wherein, the value range of the transformation processing center angle is determined according to the synthetic aperture angle; Based on the near-field test observation matrix and the far-field test observation matrix, a transfer matrix for converting near-field scattering characteristic data into far-field scattering characteristic data is calculated. The transfer matrix is ​​updated according to the preset test frequency and the transformation processing center angle to calculate all the far-field scattering characteristic data of the target under test.

2. The method as described in claim 1, characterized in that, The step of establishing near-field and far-field test observation matrices for the target under test within the divided grid regions includes: Based on the selected test frequency and transformation processing center angle, a near-field test observation matrix is ​​established to convert the target's scattering center distribution into complex scattering data measured in the near field. Based on the preset reconstruction angle range and reconstruction angle sequence, a far-field test observation matrix is ​​established to convert the target's scattering center distribution into standard far-field RCS data.

3. The method as described in claim 2, characterized in that, The near-field test observation matrix is ​​established using the following formula: In the formula, f p For testing frequency; θ q To change the center angle; a m,n The element in the m-th row and n-th column of the near-field test observation matrix; R m,n The distance from the nth grid point to the center of the measuring antenna at the mth target rotation angle is given by the center of the measuring antenna as the origin of the coordinate system. θ m Indicated by θ q Centered on Θ Within the range of m One angle; x n Represents the first [unit] within the divided grid region. n The coordinates of each grid point.

4. The method as described in claim 3, characterized in that, The far-field test observation matrix is ​​established using the following formula: in, b k,j The far-field test observation matrix is ​​the first k line, number j Column elements; R k,j To reconstruct the angle range with the target's rotation center as the origin. Inner k From the perspective of individual target reconstruction Next j The distance between each grid point and the origin; x j For the first grid region obtained by division j The coordinates of each grid point.

5. The method as described in claim 1, characterized in that, The transfer matrix T K×M It is calculated using the following formula: in, A M×N This is the near-field test observation matrix; B K×N This is the far-field test observation matrix.

6. An improved near-field and far-field data transformation device based on a transfer matrix, characterized in that, The apparatus, used in the method of any one of claims 1-5, comprises: The first calculation module is used to calculate the synthetic aperture angle required for the transformation calculation based on the maximum size of the target under test on the rotation plane and the distance from the center of the measuring antenna to the target scattering center. The modeling module is used to perform one-dimensional gridding of the area where the target is located along the horizontal direction, and to establish the near-field test observation matrix and far-field test observation matrix of the target in the gridded area respectively; wherein, the value range of the transformation processing center angle is determined according to the synthetic aperture angle required for the transformation calculation; The second calculation module is used to calculate, based on the near-field test observation matrix and the far-field test observation matrix, a transfer matrix for converting near-field scattering characteristic data into far-field scattering characteristic data. The third calculation module is used to update the transfer matrix according to the preset test frequency and the transformation processing center angle, and calculate all the far-field scattering characteristic data of the target under test.

7. A computer device, characterized in that, The computer device includes a memory and a processor. The memory is used to store computer programs, and the processor is used to execute the computer programs stored in the memory to implement the steps of the method according to any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the steps of the method described in any one of claims 1-5.

9. A computer program product, characterized in that, Includes a computer program, which, when executed by a processor, implements the steps of the method according to any one of claims 1-5.

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