A method for constructing a target characteristic library based on a measured data characteristic model

Abstract

This invention relates to a method for constructing a target characteristic library based on a measured data characteristic model, belonging to the field of electromagnetic scene simulation technology. It solves the technical problem of the lack of a highly realistic target characteristic library applicable to indoor scenarios in existing technologies. The method for constructing the target characteristic library includes: acquiring and processing measured radar target echo data under various outdoor test scenarios to obtain corresponding range-Doppler data; selecting target regions on the acquired range-Doppler data and labeling the target type, location range, radar equipment parameters, and target parameters of the target regions; for each target region, extracting all strong scattering points and their characteristic vectors within the target region to obtain a target scattering characteristic model for that target region; and summarizing the target type, radar equipment parameters, target parameters, and target scattering characteristic model for each target region to form a target characteristic library.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic scene simulation technology, and in particular to a method for constructing a target characteristic library based on a measured data characteristic model. Background Technology

[0002] Currently, with the increasing complexity of radar jamming countermeasure scenarios, comprehensive verification of radar jamming countermeasure performance has become more difficult. Passive jamming primarily involves various decoys. Verifying radar's anti-decoy performance through field tests across various scenarios is too costly. Therefore, using indoor simulation of electromagnetic jamming countermeasure scenarios is the future direction. Indoor electromagnetic scenario simulation allows interaction with the radar in an anechoic chamber via signal sources and other equipment, simulating echoes from targets and decoys detected by the radar during operation, thus enabling testing of the radar's indoor hardware and software. Currently, decoys and targets are becoming increasingly similar in shape, and radars are employing full polarization and high-resolution range to enhance their detection capabilities. Therefore, to effectively verify the radar's target and decoy identification performance in the indoor field, it is necessary to realistically simulate the polarization and range characteristics of the indoor electromagnetic scenario.

[0003] Since indoor electromagnetic scene simulation requires the support of measured data, how to construct a target characteristic library that meets the realism requirements of indoor scene applications is an urgent technical problem to be solved. Summary of the Invention

[0004] Based on the above analysis, the embodiments of the present invention aim to provide a method for constructing a target characteristic library based on a measured data characteristic model, which can solve the technical problem in the prior art of lacking a highly realistic target characteristic library applicable to indoor scenarios.

[0005] This invention discloses a method for constructing a target characteristic library based on a measured data characteristic model, comprising:

[0006] Acquire and process measured radar target echo data under various field test scenarios, and obtain corresponding range-Doppler data;

[0007] Select the target area on the acquired range-Doppler data and label the target area with the target type, location range, radar equipment parameters, and target parameters;

[0008] For each target region, extract all strong scattering points and their characteristic vectors in the target region to obtain the target scattering characteristic model of the target region.

[0009] The target type, radar equipment parameters, target parameters, and target scattering characteristic model of each target area are compiled to form a target characteristic library.

[0010] Based on the above solution, the present invention also makes the following improvements:

[0011] Furthermore, the target scattering characteristic model for each target region is obtained by performing the following steps:

[0012] Based on the marked location range of the target area, extract the distance-Doppler data of the target area;

[0013] Obtain the point of highest energy scattering in the distance-Doppler data for the target region;

[0014] Determine whether the energy of the scattering point is greater than or equal to a set multiple of the average energy of the background noise in the Doppler data over the entire distance to the target region.

[0015] If so, the scattering point is extracted as a strong scattering point, and the characteristic vector of the strong scattering point is obtained; then, the strong scattering point is removed from the range-Doppler data of the target area, the range-Doppler data of the target area is updated, and the process jumps to the step of finding the scattering point with the highest energy.

[0016] Otherwise, the process of extracting the strong scattering points and their characteristic vectors in the target region ends; by summarizing all the strong scattering points and their characteristic vectors in the target region, the target scattering characteristic model of the target region can be constructed.

[0017] Furthermore, the characteristic vector of the strong scattering point includes the coordinates of the strong scattering point and the normalized scattering parameter set of the strong scattering point.

[0018] Furthermore, the normalized scattering parameter set of the strong scattering point includes the normalized scattering parameters of the strong scattering point on the four polarization channels HH, HV, VH, and VV.

[0019] Furthermore, the normalized scattering parameters of the strong scattering points in the four polarization channels HH, HV, VH, and VV are determined as follows:

[0020] Obtain the distance-Doppler data to the target point;

[0021] Using the range-Doppler data of an ideal point target, complex coefficient decomposition is performed on the four polarization channels HH, HV, VH, and VV of a strong scattering point to obtain the scattering parameters of the strong scattering point in the corresponding polarization channel.

[0022] Based on the RCS normalization method, the scattering parameters on each polarization channel are normalized to obtain the normalized scattering parameters of the strong scattering point on the corresponding polarization channel.

[0023] Furthermore, the distance-Doppler data of the ideal point target is obtained through the following methods:

[0024] The transmitted wave pattern under the field test scenario is used as the echo of the ideal point target, and the range-Doppler data of the ideal point target is obtained through pulse compression and coherent accumulation processing.

[0025] Furthermore, the coordinates of the strong scattering point are the distance of the strong scattering point in the target area minus the distance and Doppler position in the Doppler data.

[0026] Furthermore, the target types include: ship-type targets, angle-reflecting targets, and chaff-type targets.

[0027] Furthermore, the radar equipment parameters include radar band and polarization state;

[0028] The polarization state of the radar equipment in the field test scenario is full polarization.

[0029] Furthermore, the target parameters include the incident complementary angle;

[0030] For ship-type targets, the target parameters also include the observed hull angle and radial velocity.

[0031] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0032] The method for constructing a target characteristic library based on a measured data characteristic model provided by this invention has the following advantages:

[0033] 1. By constructing a target scattering characteristic model using measured data characteristic extraction, the radar target echo range profile and Doppler dimension characteristics are more realistic, which can meet the requirements of high-resolution radar recognition performance testing environment in indoor scenarios.

[0034] 2. When the target feature library in this embodiment is used for indoor scene construction, it can enhance the reliability of the indoor scene. At the same time, the target polarization characteristics are simulated with high fidelity in the signal echoes of various polarization states in the indoor scene, which can reliably meet the requirements for target recognition algorithm verification based on polarization information.

[0035] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0036] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0037] Figure 1 Flowchart of the method for constructing a target characteristic library based on a measured data characteristic model;

[0038] Figure 2Flowchart for another method of constructing a target characteristic library based on a measured data characteristic model. Detailed Implementation

[0039] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0040] A specific embodiment of the present invention discloses a method for constructing a target characteristic library based on a measured data characteristic model, the flowchart of which is shown below. Figure 1 and Figure 2 As shown, the methods for constructing the target feature library include:

[0041] Step S1: Acquire and process measured radar target echo data under various field test scenarios, and obtain the corresponding range-Doppler data;

[0042] In the field test scenarios constructed in this embodiment, each field test scenario contains at least one target. Since the target characteristic library constructed in this embodiment is used for constructing indoor test scenarios, in order to be applicable to different indoor test scenarios, the various field test scenarios in this embodiment should cover as many targets as possible that may be involved in the indoor test scenarios. At the same time, after the field test scenarios are constructed, radar echo data under each field test scenario are collected through actual measurement as the corresponding measured radar target echo data.

[0043] In this embodiment, range-Doppler data corresponding to the measured radar target echo data is obtained by performing pulse compression and coherent accumulation processing on the measured radar target echo data under the field test scenario.

[0044] Step S2: Select the target area on the acquired range-Doppler data and label the target area with the target type, location range, radar equipment parameters and target parameters.

[0045] After acquiring range-Doppler data, regions with significantly higher energy than the background noise can be selected as target areas. It should be noted that if there are more than one target in a field test scenario, determining the target area also requires utilizing information such as the radar-target range (and, for ship-type targets, the observed hull angle) recorded during the field test to distinguish the target areas corresponding to each target.

[0046] After delineating the target area, the target type, location range, radar equipment parameters, and target parameters within the target area can be marked; preferably,

[0047] Target types include: ship targets, angle-reflecting targets, and chaff targets; for example, ship targets are distinguished by ship type; angle-reflecting targets are distinguished by angle-reflecting type; and chaff targets are distinguished by chaff type.

[0048] Location range indicates the coordinate information of the target area in the distance-Doppler data;

[0049] Radar equipment parameters include: radar band and polarization state. To effectively utilize the test conditions of the field test scenario, the radar polarization state should be set to full polarization under the field test scenario.

[0050] Target parameters include the incident angle; specifically, for ship-type targets, the target parameters also include the observed hull angle and radial velocity; in actual processing, the radar-target distance also needs to be recorded for calculating the incident angle. The incident angle refers to the angle between the beam direction and the horizontal plane of the target position; the observed hull angle refers to the angle between the direction the radar is pointing directly at the target and the ship's heading; the radial velocity refers to the target's speed in the direction the radar is pointing directly at the target.

[0051] Step S3: For each target region, extract all strong scattering points and their characteristic vectors in the target region to obtain the target scattering characteristic model of the target region;

[0052] Specifically, the process performs the following operations:

[0053] Step S31: Extract the distance-Doppler data of the target area based on the marked location range of the target area;

[0054] Step S32: Obtain the scattering point with the highest energy in the distance-Doppler data of the target area;

[0055] Step S33: Determine whether the energy of the scattering point is greater than or equal to a set multiple of the total distance of the target region minus the average energy of the background noise in the Doppler data (i.e., the average energy of the non-target region in the total distance minus the average energy of the Doppler data).

[0056] If so, the scattering point is extracted as a strong scattering point, and the characteristic vector of the strong scattering point is obtained; then, the strong scattering point is removed from the range-Doppler data of the target area, the range-Doppler data of the target area is updated, and the process jumps to step S32, that is, to find the scattering point with the highest energy again in the updated range-Doppler data of the target area.

[0057] Otherwise, the process of extracting the strong scattering points and their characteristic vectors in the target region ends;

[0058] Step S34: By summarizing all strong scattering points and their characteristic vectors in the target area, a target scattering characteristic model of the target area can be constructed.

[0059] In actual implementation, this setting factor is set based on the distinguishability between the target and background noise, and the accuracy requirements of the target feature library storage. For example, the setting factor is 4 times.

[0060] In this embodiment, the extracted characteristic vector of the strong scattering point includes:

[0061] Coordinates of the strong scattering point: distance of the strong scattering point in the target area - distance and Doppler position in the Doppler data;

[0062] Normalized scattering parameter set for strong scattering points: Normalized scattering parameters of strong scattering points in the four polarization channels HH, HV, VH, and VV.

[0063] In this embodiment, the normalized scattering parameters of the strong scattering points on the four polarization channels HH, HV, VH, and VV are determined in the following way:

[0064] (1) Obtain the range-Doppler data of the ideal point target; Specifically, the transmitted wave code pattern under the field test scenario is used as the echo of the ideal point target, and the range-Doppler data of the ideal point target is obtained through pulse compression and coherent accumulation processing.

[0065] (2) Using the range-Doppler data of the ideal point target, perform complex coefficient decomposition on the four polarization channels HH, HV, VH and VV respectively on the strong scattering point to obtain the scattering parameters of the strong scattering point on the corresponding polarization channel.

[0066] (3) Based on the RCS (Radar Cross Section) normalization method, the scattering parameters on each polarization channel are normalized to obtain the normalized scattering parameters of the strong scattering point on the corresponding polarization channel. This yields the normalized scattering parameters of the strong scattering point on the four polarization channels HH, HV, VH, and VV. In this process, the RCS normalization method completely eliminates sensor parameters and scene parameters.

[0067] For example, this embodiment also provides an expression for an RCS normalization method, using the HH polarization channel as an example for illustration; other polarization channels are similar:

[0068] RCS hh =10·lg(P) hh )+40·lg(R hh )+AGC-20·log10(τ·f s )-20·lg(λ)+L S -Pt -2G-120+ΔP1+ΔP2 (1)

[0069] Among them, RCS hh P is the normalized scattering parameter of the strong scattering point in the HH polarization channel. hh R represents the power of the strong scattering point in the HH polarization channel. hh The distance between the strong scattering point and the radar on the HH polarization channel; AGC is the receiver's automatic gain control value, τ is the pulse width, and f s L is the sampling rate, λ is the wavelength; S For system losses, P t Transmit power, G is antenna gain, ΔP1 is a specific coding compensation amount, these parameters are determined according to the equipment's own situation; ΔP2 is atmospheric attenuation compensation. Atmospheric attenuation compensation uses empirical values.

[0070] It should be noted that the RCS normalization method is not unique. In practical applications, specific modulation can be performed based on sensor parameters and scene parameters.

[0071] By summarizing all strong scattering points and their characteristic vectors in the target area, a target scattering characteristic model for that area can be constructed. The representation of the target scattering characteristic model is shown in Table 1. Each target scattering characteristic model consists of multiple scattering points. Taking the target scattering characteristic model C1 corresponding to ship type 1 as an example, in C1, R... i and D i S represents the distance and Doppler position of the i-th strong scattering point in the target scattering characteristic model, respectively. i_hh ,S i_hv ,S i_vh ,S i_vv This represents the normalized scattering parameter of the i-th strong scattering point in the target scattering characteristic model across the four polarization channels HH, HV, VH, and VV. i = 1, 2, ..., N1, where N1 is the total number of strong scattering points in the target scattering characteristic model C1.

[0072] Step S4: Summarize the target type, radar equipment parameters, target parameters, and target scattering characteristic model for each target area to form a target characteristic library;

[0073] For example, some examples in the target feature library are represented as shown in Table 1.

[0074] Table 1. Examples of contents of the target feature library

[0075]

[0076] It should be noted that once the requirements for setting up the indoor scene are determined, the target type, radar band, and target parameters of the simulated target can be determined according to the requirements. Then, the target scattering characteristic model matching each simulated target can be retrieved from the target characteristic library.

[0077] It should be clarified that the matching here refers to: finding a target data in the target characteristic library that is consistent with the target type and radar band of the simulated target and whose target parameters meet the preset threshold deviation requirements, and using the target scattering characteristic model in the target data as the target scattering characteristic model of the simulated target.

[0078] Preferably, the target parameters satisfying the preset threshold deviation requirement means that: when each parameter in the target parameters of the simulated target is compared with the corresponding parameter in the target characteristic library, each parameter should satisfy the threshold deviation of that parameter.

[0079] This process allows for the retrieval of target scattering characteristic models from the target characteristic library that match the simulated targets.

[0080] In summary, this embodiment provides a method for constructing a target characteristic library based on a measured data characteristic model. This method first acquires the range-Doppler data corresponding to measured radar target echo data and annotates the target region. Then, it extracts all strong scattering points and their characteristic vectors from each target region to obtain the target scattering characteristic model for that region. Finally, it summarizes the target type, radar equipment parameters, target parameters, and target scattering characteristic model for each target region to form a target characteristic library. Therefore, this embodiment, by employing a measured data characteristic extraction method to construct the target scattering characteristic model, achieves more realistic radar target echo range profiles and Doppler dimension characteristics, meeting the requirements of high-resolution radar recognition performance testing environments in indoor scenarios. Furthermore, using the target characteristic library in this embodiment for indoor scenario construction enhances the reliability of indoor scenarios. Simultaneously, the simulation of target polarization characteristics in signal echoes simulating various polarization states in indoor scenarios exhibits high realism, reliably meeting the requirements for verifying target recognition algorithms based on polarization information.

[0081] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0082] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for constructing a target property library based on a measured data property model, characterized in that, The method comprises the following steps: acquiring and processing measured radar target echo data under various outfield test scenarios to obtain corresponding range-Doppler data; framing a target region on the acquired range-Doppler data and labeling the target type, location range, radar device parameter and target parameter of the target region; if there is more than one target in the outfield test scenario, distinguishing the target regions corresponding to each target based on the radar-target distances of each target recorded during the outfield test; for each target region, extracting all strong scattering points and their characteristic vectors in the target region to obtain a target scattering characteristic model of the target region; summarizing the target type, radar device parameter, target parameter and target scattering characteristic model of each target region to form a target characteristic library; the target scattering characteristic model of each target region is obtained by performing the following steps: extracting the range-Doppler data of the target region according to the labeled location range of the target region; acquiring the scattering point with the maximum energy in the range-Doppler data of the target region; determining whether the energy of the scattering point is greater than or equal to a set multiple of the average energy of the background noise in the entire range-Doppler data where the target region is located, if yes, extracting the scattering point as a strong scattering point and acquiring the characteristic vector of the strong scattering point; then, eliminating the strong scattering point in the range-Doppler data of the target region, updating the range-Doppler data of the target region and jumping to the step of finding the scattering point with the maximum energy; otherwise, the process of extracting the strong scattering points and their characteristic vectors of the target region ends; summarizing all strong scattering points and their characteristic vectors of the target region to construct a target scattering characteristic model of the target region.

2. The method of claim 1, wherein the method further comprises: The characteristic vector of the strong scattering point comprises the coordinates of the strong scattering point and a normalized scattering parameter set of the strong scattering point.

3. The method of claim 2, wherein the measured data characteristic model is a model of a measured data characteristic of a target. The normalized scattering parameter set of the strong scattering point comprises normalized scattering parameters of the strong scattering point in HH, HV, VH and VV polarization channels.

4. The method of claim 3, wherein the measured data characteristic model is constructed by: The normalized scattering parameters of the strong scattering point in HH, HV, VH and VV polarization channels are determined by the following method: acquiring the range-Doppler data of an ideal point target; performing complex coefficient decomposition of the strong scattering point in HH, HV, VH and VV polarization channels respectively by using the range-Doppler data of the ideal point target to obtain the scattering parameters of the strong scattering point in the corresponding polarization channel; based on the RCS normalization method, performing normalization processing on the scattering parameters in each polarization channel respectively to obtain the normalized scattering parameters of the strong scattering point in the corresponding polarization channel.

5. The method of claim 4, wherein the measured data characteristic model-based target characteristic library construction method is characterized by, The range-Doppler data of the ideal point target is acquired by the following method: using the transmission wave code type under the outfield test scenario as the ideal point target echo, and obtaining the range-Doppler data of the ideal point target through pulse compression and coherent accumulation processing.

6. The method of claim 2-5, wherein, The coordinates of the strong scattering point are the distance and Doppler position of the strong scattering point in the range-Doppler data of the target region.

7. The method of claim 1, wherein the method further comprises: The target type comprises a ship target, a corner reflector target and a chaff target.

8. The method of claim 7, wherein the method further comprises: The radar device parameter comprises a radar wave band and a polarization state; The polarization state of the radar device under the outfield test scenario is full polarization.

9. The method of claim 7, wherein the method further comprises: The target parameter comprises an incident angle. For a ship-like target, the target parameters further include an observed broadside angle and a radial velocity.

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