A synthetic aperture radar imaging simulation method and system

Abstract

The present invention discloses a synthetic aperture radar imaging simulation method and system, and relates to the field of synthetic aperture radar. The method comprises: obtaining structural dimension information and spatial coordinate information of a simulation object, creating a geometric model of the simulation object according to the structural dimension information and the spatial coordinate information, meshing the geometric model after setting material properties, obtaining mesh model data, constructing an echo signal of the geometric model according to the mesh model data, imaging processing the echo signal according to a synthetic aperture radar imaging algorithm, and obtaining a SAR image of the geometric model. The scheme can greatly simplify the echo modeling process in the synthetic aperture radar imaging simulation process, improve the accuracy of the echo model, and provide strong support for the synthetic aperture radar imaging simulation.

Description

Technical Field

[0001] The invention relates to the field of synthetic aperture radar, and in particular to a synthetic aperture radar imaging simulation method and system. Background Art

[0002] Synthetic aperture radar receives electromagnetic waves backscattered by the target during the relative motion between the radar and the target, and uses the target information carried by the electromagnetic waves to perform imaging. However, at present, whether it is satellite-borne or airborne synthetic aperture radar, it is difficult to obtain the original electromagnetic waves of certain specific targets, which also makes it difficult to obtain the SAR image information of the target. In order to verify the synthetic aperture radar imaging algorithm and obtain the SAR image information of these targets of interest, it is necessary to model them to simulate the echoes generated by the model and use them for synthetic aperture radar imaging processing.

[0003] In the traditional synthetic aperture radar imaging simulation process, the target echo modeling method is mainly to discretize the model into multiple point targets and construct the model echo according to the spatial position information of the point targets. However, when the target of interest has the characteristics of large volume and complex appearance structure, in order to accurately simulate the echo generated by the target, the target model is discretized into multiple point targets with huge number and complex spatial position distribution. If all point targets need to be created one by one by the simulator, it is undoubtedly a complicated and extremely time-consuming task. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a synthetic aperture radar imaging simulation method and system in view of the deficiencies in the prior art.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A synthetic aperture radar imaging simulation method, comprising:

[0007] Obtain the structural size information and spatial coordinate information of the simulation object;

[0008] Creating a geometric model of the simulation object according to the structural size information and the spatial coordinate information;

[0009] Meshing the geometric model after setting the material properties to obtain mesh model data;

[0010] Constructing an echo signal of the geometric model according to the grid model data;

[0011] The echo signal is imaged and processed according to a synthetic aperture radar imaging algorithm to obtain a SAR image of the geometric model.

[0012] The beneficial effects of the present invention are as follows: based on the demand for synthetic aperture radar imaging simulation of a specific target, the present invention provides a synthetic aperture radar imaging simulation method based on ANSYS modeling, which, by means of ANSYS parametric modeling and the ability to output a target discrete point model, can greatly simplify the echo modeling process in the synthetic aperture radar imaging simulation process, improve the accuracy of the echo model, and provide strong support for synthetic aperture radar imaging simulation.

[0013] When the target of interest has the characteristics of large size and complex appearance and structure, in order to accurately simulate the echo generated by the target, the target model is discretized into multiple point targets with huge number and complex spatial position distribution. This scheme can reduce the workload of echo modeling in the synthetic aperture radar imaging simulation process.

[0014] Furthermore, the echo signal of constructing the geometric model also includes:

[0015] Importing the mesh model data into Matlab, drawing the appearance of the geometric model including discrete points; comparing the appearance of the geometric model with the appearance of the simulation object to obtain a comparison result;

[0016] Deleting and / or modifying the discrete point information according to the comparison result to obtain processed grid model data;

[0017] The step of constructing the echo signal of the geometric model according to the grid model data specifically includes:

[0018] The echo signal of the geometric model is constructed according to the processed mesh model data.

[0019] The beneficial effect of adopting the above further scheme is that: this scheme obtains processed mesh model data by deleting and / or modifying discrete point information according to the comparison result, thereby eliminating defects in certain details of the nodes divided by the ANSYS mesh.

[0020] Furthermore, the meshing of the geometric model after setting the material properties to obtain mesh model data specifically includes: setting the meshing method;

[0021] According to the meshing method, the geometric model is meshed to obtain mesh model data.

[0022] The beneficial effect of adopting the above further scheme is: through the grid division method of this scheme, the speed of grid division is accelerated and the computational burden of the synthetic aperture radar imaging algorithm is reduced.

[0023] Furthermore, the division method includes: dividing the geometric model after setting the material properties according to the number of divided grids and the type of grids, or dividing the geometric model after setting the material properties according to the size of the divided grids and the type of grids.

[0024] Furthermore, the spatial coordinate information is position information of the simulation object in three directions of X, Y and Z at the geometric center.

[0025] Another technical solution of the present invention to solve the above technical problems is as follows:

[0026] A synthetic aperture radar imaging simulation system comprises: a simulation object acquisition module, a geometric model creation module, a grid division module, an echo signal construction module and an imaging module;

[0027] The simulation object acquisition module is used to acquire the structural size information and spatial coordinate information of the simulation object;

[0028] The geometric model creation module is used to create a geometric model of the simulation object according to the structural size information and the spatial coordinate information;

[0029] The meshing module is used to mesh the geometric model after setting the material properties to obtain mesh model data;

[0030] The echo signal construction module is used to construct the echo signal of the geometric model according to the grid model data;

[0031] The imaging module is used to perform imaging processing on the echo signal according to the synthetic aperture radar imaging algorithm to obtain the SAR image of the geometric model.

[0032] The beneficial effects of the present invention are as follows: based on the demand for synthetic aperture radar imaging simulation of a specific target, the present invention provides a synthetic aperture radar imaging simulation method based on ANSYS modeling, which, by means of ANSYS parametric modeling and the ability to output a target discrete point model, can greatly simplify the echo modeling process in the synthetic aperture radar imaging simulation process, improve the accuracy of the echo model, and provide strong support for synthetic aperture radar imaging simulation.

[0033] When the target of interest has the characteristics of large size and complex appearance and structure, in order to accurately simulate the echo generated by the target, the target model is discretized into multiple point targets with huge number and complex spatial position distribution. This scheme can reduce the workload of echo modeling in the synthetic aperture radar imaging simulation process.

[0034] Furthermore, it also includes: a selection processing module, which is used to import the mesh model data into Matlab and draw the appearance of the geometric model including discrete points;

[0035] Comparing the appearance of the geometric model with the appearance of the simulation object to obtain a comparison result;

[0036] Deleting and / or modifying the discrete point information according to the comparison result to obtain processed grid model data;

[0037] The echo signal construction module is specifically used to construct the echo signal of the geometric model according to the processed mesh model data.

[0038] The beneficial effect of adopting the above further scheme is that: this scheme obtains processed mesh model data by deleting and / or modifying discrete point information according to the comparison result, thereby eliminating defects in certain details of the nodes divided by the ANSYS mesh.

[0039] Furthermore, the grid division module is specifically used for

[0040] Setting the grid division method;

[0041] According to the meshing method, the geometric model is meshed to obtain mesh model data.

[0042] The beneficial effect of adopting the above further scheme is: through the grid division method of this scheme, the speed of grid division is accelerated and the computational burden of the synthetic aperture radar imaging algorithm is reduced.

[0043] Furthermore, the division method includes: dividing the geometric model after setting the material properties according to the number of divided grids and the type of grids, or dividing the geometric model after setting the material properties according to the size of the divided grids and the type of grids.

[0044] Furthermore, the spatial coordinate information is position information of the simulation object in three directions of X, Y and Z at the geometric center.

[0045] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of a flow chart of a synthetic aperture radar imaging simulation method provided by an embodiment of the present invention;

[0047] Figure 2 A structural block diagram of a synthetic aperture radar imaging simulation system provided by an embodiment of the present invention;

[0048] Figure 3 A schematic diagram of a simplified tank model built by ANSYS provided for other embodiments of the present invention;

[0049] Figure 4 A schematic diagram of a target discrete point model provided for other embodiments of the present invention;

[0050] Figure 5 A schematic diagram of a target discrete point model after selection provided by other embodiments of the present invention;

[0051] Figure 6 A schematic diagram of a 0.5m×0.5m resolution SAR image generated according to other embodiments of the present invention;

[0052] Figure 7 A schematic diagram of a 1m×1m resolution SAR image generated according to another embodiment of the present invention. DETAILED DESCRIPTION

[0053] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention but not to limit the scope of the present invention.

[0054] like Figure 1 As shown, a synthetic aperture radar imaging simulation method provided by an embodiment of the present invention includes:

[0055] S1, obtaining the structural dimension information and spatial coordinate information of the simulation object; wherein the objects that can be simulated include: ground or sea targets with complex shapes such as ships, tanks, and airplanes.

[0056] It should be noted that the structural size of the simulation object should be much larger than the resolution of the synthetic aperture radar imaging in the distance and azimuth. The spatial coordinates of the simulation object should be within the imaging area of ​​the synthetic aperture radar.

[0057] S2, creating a geometric model of the simulation object according to the structural size information and the spatial coordinate information;

[0058] In one embodiment, the geometric model of the simulation object is created using the DesignModeler module of ANSYS Workbench. It should be noted that when modeling, the parameter units of the DesignModeler module should be set to be consistent with the units used in the synthetic aperture radar imaging simulation. In order to facilitate modeling and observe image results, the geometric center of the model should be located at the origin of the coordinate system as much as possible.

[0059] S3, meshing the geometric model after setting the material properties to obtain mesh model data;

[0060] In one embodiment, meshing the created geometric model is performed in the Mesh module of ANSYS Workbench, and meshing the created geometric model in the Mesh module of ANSYS Workbench specifically includes the following steps:

[0061] S301, import the model data of the DesignModeler module into the Mesh module.

[0062] S302, setting the material properties of the model in the mesh module.

[0063] It should be noted that the mesh module must first set the material properties of the model before it can perform meshing operations on the model. The model material properties here can be arbitrarily selected from the ANSYS material library. The material properties have no effect on the meshing results, but they cannot be empty.

[0064] S303, setting the meshing method of the model.

[0065] It should be noted that the meshing in the mesh module requires the size of the mesh to be set first. In order to speed up the meshing rate and reduce the computational burden of the synthetic aperture radar imaging algorithm, the mesh size can be set to half of the algorithm resolution, and the meshing method can be selected as multi-region meshing.

[0066] S304, start meshing and output mesh model data.

[0067] It should be noted that in order to facilitate the data reading operation in the subsequent steps and the simulation personnel to check the correctness of the data, the output model data is in .xls file format, and the node number and coordinate information will be displayed in a table.

[0068] Prior to S4, it could also include:

[0069] Use Matlab to import model data, check model appearance, and modify model data.

[0070] It should be noted that when checking the appearance of the model, one should mainly observe whether the appearance of the model is consistent with that of the simulation object. Since the nodes divided by the ANSYS mesh have defects in some details, the simulation personnel need to further edit the node information according to the actual situation.

[0071] S4, constructing the echo signal of the geometric model according to the grid model data;

[0072] In one embodiment, S4 specifically includes: constructing an echo signal of a target model according to a first formula, where the first formula is:

[0073]

[0074] In the formula, σ k is the complex scattering coefficient of the kth node, w is the amplitude factor of the signal, c is the speed of light, T pt is the pulse repetition period, R(t s ) is the node at (t, t a ) In the case of common imaging simulation, the influence of complex scattering coefficient and amplitude factor on echo can be ignored in order to simplify the echo model.

[0075] It should be noted that R(t s ) is the node at (t, t a ) when the slope distance. The calculation formula is:

[0076]

[0077] Where X, Y, and Z are the coordinates of the spatial rectangular coordinate system.

[0078] S5, performing imaging processing on the echo signal according to a synthetic aperture radar imaging algorithm to obtain a SAR image of the geometric model.

[0079] In a certain embodiment, S5 specifically includes: using a synthetic aperture radar imaging algorithm to perform imaging processing on the echo signal, obtaining a SAR image of the model and evaluating the image effect. It should be understood that before imaging the simulation target of interest, the imaging algorithm should be used to image a single point target, and after the impulse response function of the point target is evaluated to be correct, the simulation target of interest is imaged. The imaging simulation process should use different resolutions to image the target. Evaluating the image effect mainly includes comparing the appearance of the target in the SAR image at different resolutions and comparing the appearance of the target in the SAR image with the actual target appearance.

[0080] Based on the demand for synthetic aperture radar imaging simulation of specific targets, the present invention provides a synthetic aperture radar imaging simulation method based on ANSYS modeling. With the help of ANSYS parametric modeling and the ability to output target discrete point models, this method can greatly simplify the echo modeling process in the synthetic aperture radar imaging simulation process, improve the accuracy of the echo model, and provide strong support for synthetic aperture radar imaging simulation.

[0081] When the target of interest has the characteristics of large size and complex appearance and structure, in order to accurately simulate the echo generated by the target, the target model is discretized into multiple point targets with huge number and complex spatial position distribution. This scheme can reduce the workload of echo modeling in the synthetic aperture radar imaging simulation process.

[0082] Optionally, in any of the above embodiments, the step of constructing the echo signal of the geometric model further includes:

[0083] Importing the mesh model data into Matlab, drawing the appearance of the geometric model including discrete points; comparing the appearance of the geometric model with the appearance of the simulation object to obtain a comparison result;

[0084] Deleting and / or modifying the discrete point information according to the comparison result to obtain processed grid model data;

[0085] The step of constructing the echo signal of the geometric model according to the grid model data specifically includes:

[0086] The echo signal of the geometric model is constructed according to the processed mesh model data.

[0087] This solution obtains processed mesh model data by deleting and / or modifying discrete point information according to the comparison results, thereby eliminating defects in certain details of nodes divided by the ANSYS mesh.

[0088] Optionally, in any of the above embodiments, meshing the geometric model after setting the material properties to obtain mesh model data specifically includes:

[0089] Setting the grid division method;

[0090] According to the meshing method, the geometric model is meshed to obtain mesh model data.

[0091] Through the grid division method of this scheme, the rate of grid division is accelerated and the computational burden of the synthetic aperture radar imaging algorithm is reduced.

[0092] Optionally, in any of the above embodiments, the division method includes: meshing the geometric model after setting material properties according to the number of divided grids and the type of grids, or meshing the geometric model after setting material properties according to the size of the divided grids and the type of grids.

[0093] Optionally, in any of the above embodiments, the spatial coordinate information is position information of the simulation object in three directions of X, Y and Z of the geometric center.

[0094] In one embodiment, a synthetic aperture radar imaging simulation method based on ANSYS modeling is simulated and verified. The synthetic aperture radar imaging algorithm adopts the BP algorithm. The experimental parameters are shown in Table 1. The simplified tank model built by ANSYS is as follows: Figure 3 As shown; after meshing the simplified tank model and then importing it into Matlab, the target discrete point model is displayed as follows Figure 4 shown; Figure 4 The target discrete point model after further selection of the model is as follows Figure 5 As shown; finally, the target discrete point model after the selection process is echo constructed and imaged, and the obtained simplified tank model 0.5m×0.5m resolution SAR image and 1m×1m resolution SAR image are shown as follows Figure 6 , Figure 7 shown.

[0095] parameter Numeric Carrier frequency 35GHz Pulse Width 1μs Oblique angle 0° PRF 1000Hz

[0096] Table 1

[0097] It can be seen that compared with the method of creating a synthetic aperture radar imaging model based on point coordinates, the synthetic aperture radar imaging simulation method based on ANSYS modeling provided in this embodiment simplifies the synthetic aperture radar imaging modeling process and saves the time of imaging simulation by leveraging the convenience of ANSYS software for creating complex models and the ability to discretize the model into multiple point targets. It can adapt to synthetic aperture radar imaging simulations of various complex structural models and provide strong support for obtaining SAR image information of certain targets of interest.

[0098] In one embodiment, if Figure 2 As shown, a synthetic aperture radar imaging simulation system includes: a simulation object acquisition module 1101, a geometric model creation module 1102, a grid division module 1103, an echo signal construction module 1104 and an imaging module 1105;

[0099] The simulation object acquisition module 1101 is used to acquire the structural size information and spatial coordinate information of the simulation object;

[0100] The geometric model creation module 1102 is used to create a geometric model of the simulation object according to the structural size information and the spatial coordinate information;

[0101] The meshing module 1103 is used to mesh the geometric model after setting the material properties to obtain mesh model data;

[0102] The echo signal construction module 1104 is used to construct the echo signal of the geometric model according to the grid model data;

[0103] The imaging module 1105 is used to perform imaging processing on the echo signal according to the synthetic aperture radar imaging algorithm to obtain the SAR image of the geometric model.

[0104] Based on the demand for synthetic aperture radar imaging simulation of specific targets, the present invention provides a synthetic aperture radar imaging simulation method based on ANSYS modeling. With the help of ANSYS parametric modeling and the ability to output target discrete point models, this method can greatly simplify the echo modeling process in the synthetic aperture radar imaging simulation process, improve the accuracy of the echo model, and provide strong support for synthetic aperture radar imaging simulation.

[0105] When the target of interest has the characteristics of large size and complex appearance and structure, in order to accurately simulate the echo generated by the target, the target model is discretized into multiple point targets with huge number and complex spatial position distribution. This scheme can reduce the workload of echo modeling in the synthetic aperture radar imaging simulation process.

[0106] Optionally, in any of the above embodiments, it further comprises: a selection processing module, used to import the mesh model data into Matlab, and draw the appearance of the geometric model including discrete points;

[0107] Comparing the appearance of the geometric model with the appearance of the simulation object to obtain a comparison result;

[0108] Deleting and / or modifying the discrete point information according to the comparison result to obtain processed grid model data;

[0109] The echo signal construction module is specifically used to construct the echo signal of the geometric model according to the processed mesh model data.

[0110] This solution obtains processed mesh model data by deleting and / or modifying discrete point information according to the comparison results, thereby eliminating defects in certain details of nodes divided by the ANSYS mesh.

[0111] Optionally, in any of the above embodiments, the grid division module 1103 is specifically used for:

[0112] Setting the grid division method;

[0113] According to the meshing method, the geometric model is meshed to obtain mesh model data.

[0114] Through the grid division method of this scheme, the rate of grid division is accelerated and the computational burden of the synthetic aperture radar imaging algorithm is reduced.

[0115] Optionally, in any of the above embodiments, the division method includes: meshing the geometric model after setting material properties according to the number of divided grids and the type of grids, or meshing the geometric model after setting material properties according to the size of the divided grids and the type of grids.

[0116] Optionally, in any of the above embodiments, the spatial coordinate information is position information of the simulation object in three directions of X, Y and Z of the geometric center.

[0117] It can be understood that in some embodiments, some or all of the optional implementation modes in the above embodiments may be included.

[0118] It should be noted that the above embodiments are product embodiments corresponding to the previous method embodiments. For the description of the optional implementation methods in the product embodiments, reference can be made to the corresponding description in the above method embodiments, which will not be repeated here.

[0119] The reader should understand that in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0120] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the method embodiments described above are only illustrative, for example, the division of steps is only a logical function division, and there may be other division methods in actual implementation, such as multiple steps can be combined or integrated into another step, or some features can be ignored or not executed.

[0121] If the above method is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0122] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A synthetic aperture radar imaging simulation method, characterized in that: include: Obtain the structural size information and spatial coordinate information of the simulation object; Creating a geometric model of the simulation object according to the structural size information and the spatial coordinate information; Meshing the geometric model after setting the material properties to obtain mesh model data; Constructing an echo signal of the geometric model according to the grid model data; Performing imaging processing on the echo signal according to a synthetic aperture radar imaging algorithm to obtain a SAR image of the geometric model; The step of constructing the geometric model of the echo signal also includes: Importing the mesh model data into Matlab, and drawing the appearance of the geometric model including discrete points; Comparing the appearance of the geometric model with the appearance of the simulation object to obtain a comparison result; Deleting and / or modifying the discrete point information according to the comparison result to obtain processed grid model data; The step of constructing the echo signal of the geometric model according to the grid model data specifically includes: The echo signal of the geometric model is constructed according to the processed mesh model data.

2. A synthetic aperture radar imaging simulation method according to claim 1, characterized in that: The meshing of the geometric model after setting the material properties to obtain mesh model data specifically includes: Setting the grid division method; According to the meshing method, the geometric model is meshed to obtain mesh model data.

3. A synthetic aperture radar imaging simulation method according to claim 2, characterized in that: The division method includes: dividing the geometric model after setting the material properties according to the number of divided grids and the type of grids, or dividing the geometric model after setting the material properties according to the size of the divided grids and the type of grids.

4. A synthetic aperture radar imaging simulation method according to any one of claims 1 to 3, characterized in that: The spatial coordinate information is the position information of the simulation object in three directions of X, Y and Z at the geometric center.

5. A synthetic aperture radar imaging simulation system, characterized in that: include: Simulation object acquisition module, geometric model creation module, meshing module, echo signal construction module and imaging module; The simulation object acquisition module is used to acquire the structural size information and spatial coordinate information of the simulation object; The geometric model creation module is used to create a geometric model of the simulation object according to the structural size information and the spatial coordinate information; The meshing module is used to mesh the geometric model after setting the material properties to obtain mesh model data; The echo signal construction module is used to construct the echo signal of the geometric model according to the grid model data; The imaging module is used to perform imaging processing on the echo signal according to the synthetic aperture radar imaging algorithm to obtain the SAR image of the geometric model; It also includes: a selection processing module, which is used to import the mesh model data into Matlab and draw the appearance of the geometric model including discrete points; Comparing the appearance of the geometric model with the appearance of the simulation object to obtain a comparison result; Deleting and / or modifying the discrete point information according to the comparison result to obtain processed grid model data; The echo signal construction module is specifically used to construct the echo signal of the geometric model according to the processed mesh model data.

6. A synthetic aperture radar imaging simulation system according to claim 5, characterized in that: The grid division module is specifically used to set the grid division method; According to the meshing method, the geometric model is meshed to obtain mesh model data.

7. A synthetic aperture radar imaging simulation system according to claim 6, characterized in that: The division method includes: dividing the geometric model after setting the material properties according to the number of divided grids and the type of grids, or dividing the geometric model after setting the material properties according to the size of the divided grids and the type of grids.

8. A synthetic aperture radar imaging simulation system according to any one of claims 5 to 7, characterized in that: The spatial coordinate information is the position information of the simulation object in three directions of X, Y and Z at the geometric center.

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