One-dimensional processing method for suppressing specific scatterer echoes in radar cross section measurement

Abstract

This invention discloses a one-dimensional processing method for suppressing echoes from specific scattering objects in radar cross section (RCS) measurement, comprising the following steps: S1, acquisition and pulse compression of raw measurement data of target omnidirectional scattered echoes; S2, filtering-inverse projection two-dimensional inverse synthetic aperture radar (ISAR) imaging; S3, detection and identification of two-dimensional position parameters of specific scattering objects; S4, detection and identification of the radial distance trajectory of specific scattering objects in one-dimensional high-resolution range profiles (HRRP); S5, extraction of specific scattering objects in one-dimensional azimuth; S6, acquisition of target scattered echo data varying with frequency and azimuth after one-dimensional frequency domain processing or one-dimensional time domain processing. This invention employs the above-mentioned one-dimensional processing method for suppressing echoes from specific scattering objects in radar cross section measurement, without the need for geometric model assistance. It can effectively suppress the echo signals of specific scattering objects such as target supports and carriers that are mixed with target scattered echoes, thereby reducing the influence of background clutter and improving the accuracy of target RCS measurement.

Description

Technical Field

[0001] This invention relates to the fields of communication and radar technology, and in particular to a one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement. Background Technology

[0002] Accurate measurement of the target's radar cross section (RCS) is crucial for achieving low-scattering design and maintenance of low-observable targets. In microwave anechoic chambers and static field measurements, the target is typically mounted on a low-scattering support for stable support. During measurement, the RCS measuring radar remains stationary while the target rotates in azimuth direction via a turntable. The measuring radar acquires the scattered echoes from the target at different azimuth angles. After background cancellation and RCS calibration, the omnidirectional RCS measurement data of the target is obtained. A typical geometric relationship for target RCS field measurement is shown below. Figure 1 As shown.

[0003] The echo signals received by actual radar systems are complex signals, and include the effects of background clutter and noise from the test field. As Xu Xiaojian stated in his 2017 article, "New Technologies for Measurement and Processing of Radar Target Scattering Characteristics," the radar echo signals of the measured target and the calibration body can be expressed as follows:

[0004] M T (f)=S T (f)+B T (f)+N T (1)

[0005] and

[0006] M C (f)=S C (f)+B C (f)+N C (2)

[0007] In the formula, M T (f) and M C (f) represents the echo signals received by the radar when measuring the target and the marker, respectively; S T (f) represents the target's true echo; S C (f) represents the true echo of the calibration body; B T (f) and B C (f) represents the background echo during target measurement and standard measurement, respectively; N T and N C These represent the noise effects during target measurement and standard measurement, respectively. All echo signals mentioned above are complex phasors.

[0008] In target RCS measurement engineering applications, the signal-to-noise ratio of the echo signal can generally be improved by increasing the transmission power, adopting a ground-based planar test field configuration, and using coherent accumulation processing for the received signal. This allows the influence of noise on the target measurement signal to be ignored, and the echo measurement signal can be approximated by the following formula:

[0009] M T (f)=S T (f)+B T (f) (3)

[0010] and

[0011] M C (f)=S C (f)+B C (f) (4)

[0012] To improve the accuracy of target RCS measurement, background phasor subtraction is generally used in the calibration process. Therefore, the calibration equation for the target scattering function is:

[0013]

[0014] In the formula, The target scattering function (also known as the complex RCS, which is a quantity that needs to be measured and calibrated) is the target scattering function. The scattering function of the calibration body is a known quantity that can be obtained through precise theoretical calculations.

[0015] Therefore, the target RCS measurement calibration equation with background cancellation processing is:

[0016]

[0017] In most indoor RCS testing ranges, target and benchmark measurements are performed on the same support placed at the same distance. Therefore, the background echo B during target measurement will be... T (f) and background echo B during the determination of the standard. C (f) are the same, therefore:

[0018]

[0019] In practical RCS measurement engineering applications, the support structures used in different test sites vary. Some test sites use fixed low-scattering supports, with an azimuth turntable mounted on top of the support to drive the target to complete azimuth rotation. In this case, the scattered echo from the support forms a zero-Doppler echo signal that remains constant with the azimuth angle. In other test sites, the low-scattering support is mounted on a large turntable, and the target is then mounted on the low-scattering support. In this case, both the support and the target are driven by the azimuth turntable to complete the azimuth rotation measurement. The scattered echo from the support forms an echo signal whose amplitude and phase change with the azimuth angle rotation. Furthermore, low-scattering carriers used for target component measurement are driven by the turntable simultaneously with the target during the measurement process, completing a 360° azimuth rotation measurement. In this case, the scattered echo from the low-scattering carrier also forms an echo signal that changes with the azimuth angle rotation. These scattering structures, whether they belong to or not to the target component but are located in the target area and contribute to the scattering measurement echo, are called specific scatterers, such as target supports used in overall target measurement and carriers used in target component measurement.

[0020] Therefore, in the RCS measurement of the target whole machine or target component, the key to achieving accurate target RCS calibration measurement is how to accurately measure the scattered echo generated by the target support and carrier and other structures, and then suppress the echo of the specific scatterer (target support, carrier) mixed in with the target scattered echo.

[0021] (1) The prior art related to this invention is analyzed as follows:

[0022] The technical solution of existing technology-1: For the extraction and elimination of zero Doppler clutter signals, it utilizes auxiliary measurement devices and signal processing methods to achieve the extraction and elimination of zero Doppler clutter, such as a fixed background, in an RCS test field. The main methods include:

[0023] (a) Design a low-scattering end cap for auxiliary measurement. When measuring the background, the top of the support is "hidden" with the low-scattering end cap, just as when measuring the target. It is assumed that the echo measured at this time is mainly fixed background clutter. For example, Guidi et al. proposed several low-scattering end caps with different shapes in the 2002 paper "NRTF's 14 Foot Pylon".

[0024] (b) A background auxiliary measurement device with a constant scattering amplitude is used to complete background extraction and subsequent background cancellation processing through auxiliary measurement and signal processing. For example, Morgan et al. proposed using an object translated on a support as the background auxiliary measurement body in their 1996 paper "RCS Target Support Background Determination Using a Translating Test Body". Muth et al. proposed using an eccentric cylinder as the background auxiliary measurement body in their 2005 paper "Robust Separation of Background and Target Signals in Radar Cross Section Measurements". Wood et al. proposed using a CAM calibration body as the background auxiliary measurement body in their 2003 paper "The CAM RCS Dual-Cal Standard". The invention patent with publication number CN201610237378.2 discloses the design of a device for multiple calibration and background extraction in target RCS measurement and its signal processing method, which uses an SCAM calibration body as the background auxiliary measurement body.

[0025] (c) Using a low-scattering end cap as a background auxiliary measurement body, background extraction and subsequent background cancellation processing are completed through auxiliary measurement and signal processing, including: Xu Xiaojian proposed an all-round averaging method for background extraction in his 2012 article "A Background and Target Signal Separation Technique For Exact RCS Measurement"; the invention patent with publication number CN201610764900.2 disclosed a data domain processing method for background extraction and cancellation based on the maximum probability in "Maximum Probability Data Domain Processing Method for Background Extraction and Cancellation in Target RCS Measurement"; the invention patent with publication number CN201610764605.7 disclosed a time domain processing method for background extraction and cancellation based on the maximum probability in "Time Domain Processing Method for Background Measurement and Extraction Based on the Maximum Probability"; and the invention patent with publication number 201610813955.8 disclosed a "Background Extraction Method Based on Joint Processing of Maximum Probability Threshold and Model Prediction".

[0026] The disadvantage of existing technology-1 is that it utilizes the characteristic that a fixed background remains unchanged or changes slowly with the azimuth angle during RCS measurement to extract zero Doppler echo signals and perform background cancellation processing. Therefore, this type of technology can only extract and suppress zero Doppler signals or slowly changing echo signals such as fixed background clutter, but cannot extract and suppress echo signals of specific scatterers that change with azimuth.

[0027] (2) The prior art related to this invention is analyzed as follows:

[0028] The technical solution of existing technology-2: For the extraction and elimination of sliding scattering centers, such as the paper "Sliding Scattering Center Extraction for Streamlined RadarTargets" by Xu Xiaojian et al. in 2023, Xu Xiaojian et al. proposed to use the geometric model of the target under test to determine the geometric shape of the component structure corresponding to a specific sliding scattering center, and predict its sine and cosine trajectory with azimuth in a one-dimensional high resolution range profile (HRRP). Then, the basis tracking method is used to sparsely characterize and reconstruct the azimuth range of the specific sliding scattering center, so as to realize the extraction and suppression of the echo signal of the specific sliding scattering center.

[0029] The drawbacks of existing technology-2 are as follows: Since the method requires the use of the geometric model of the target to determine the trajectory of a specific scattering center as the azimuth angle changes, its implementation depends on the accurate geometric model of the target. However, in actual RCS measurements, it is difficult to obtain the accurate geometric shape of specific scatterers such as target supports used for overall target measurement and carriers used for target component measurement. Therefore, this method cannot extract and suppress the echoes from these specific scatterers. Furthermore, the computational load is high due to the use of a basis tracing method for sparse characterization and reconstruction of the echo signal from the scattering center. Summary of the Invention

[0030] The purpose of this invention is to provide a one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section (RCS) measurements. The technical problem to be solved is that existing methods for suppressing echo signals from scattering centers in target RCS measurements can only extract and suppress zero-Doppler clutter that remains constant with azimuth, or extract and suppress sliding scattering centers that vary with azimuth using a precise target geometric model. However, in actual RCS measurements, specific scatterers, such as target supports used in overall target measurements and carriers used in target component measurements, exhibit azimuth-dependent characteristics, and their accurate geometric shapes are difficult to obtain. Therefore, existing methods cannot suppress these specific scatterers. This invention is proposed to solve this problem.

[0031] To achieve the above objectives, the present invention provides a one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement, comprising the following steps:

[0032] S1. Acquisition of raw measurement data of target omnidirectional scattered echo and pulse compression;

[0033] S2, Filter-Inverse Projection Two-Dimensional Inverse Synthetic Aperture Radar (ISAR) Imaging;

[0034] S3. Detection and identification of two-dimensional position parameters of specific scatterers;

[0035] S4. Detection and recognition of HRRP trajectory of radial distance per azimuth of a specific scatterer in one-dimensional high-resolution range image;

[0036] S5. Azimuth-by-azimuth echo extraction of specific scatterers;

[0037] S6. After performing one-dimensional frequency domain processing or one-dimensional time domain processing, obtain the target scattered echo data that varies with frequency and azimuth.

[0038] Preferably, the specific scatterer refers to a scattering structure located in the target region that contributes to the scattering measurement echo.

[0039] Preferably, step S1 specifically includes:

[0040] A 360° omnidirectional rotation measurement of the target is performed to obtain raw measurement data of the amplitude and phase of the scattered echo that varies with frequency and azimuth angle. A one-dimensional high-resolution range profile (HRRP) of the target scattered echo that varies with azimuth is obtained by pulse compression.

[0041] Preferably, step S2 specifically includes:

[0042] The one-dimensional high-resolution range image HRRP obtained in step S1 is back-projected to achieve two-dimensional inverse synthetic aperture radar (ISAR) imaging of the target.

[0043] Preferably, step S3 specifically includes:

[0044] In the target two-dimensional inverse synthetic aperture radar (ISAR) image, specific scatterers are detected and identified to determine the precise two-dimensional position parameters of the specific scatterers.

[0045] Preferably, step S4 specifically includes:

[0046] Based on the information assistance of the two-dimensional position parameters of a specific scatterer, the one-dimensional high-resolution range image (HRRP) of the target's scattering echo, which varies with azimuth, is detected and identified azimuth-wise. That is, at each radar observation azimuth angle, the coordinate position of the corresponding reflection point on the two-dimensional image of the specific scatterer is calculated, and the radial distance of the reflection point is calculated according to the projection relationship of the observation azimuth angle, so as to obtain the trajectory parameters of the one-dimensional high-resolution range image (HRRP) of the specific scatterer that varies with azimuth.

[0047] Preferably, step S5 specifically includes:

[0048] The HRRP trajectory of a one-dimensional high-resolution range profile along a specific scatterer varies with azimuth, and the amplitude and phase information of the HRRP of the specific scatterer are extracted based on the maximum probability statistical method.

[0049] Preferably, in step S6, the one-dimensional frequency domain processing specifically includes the following steps:

[0050] S6a, Frequency Domain Processing and Echo Reconstruction

[0051] Based on the complex amplitude and radial distance of the specific scatterer HRRP extracted in step S5, the frequency domain echo signal of the specific scatterer is reconstructed.

[0052] S7a, Subtraction of data domains by orientation

[0053] For frequency domain scattered echo data in each azimuth, a phasor subtraction process is performed between the original target measurement data and the estimated data of a specific scatterer.

[0054] Preferably, in step S6, the one-dimensional time domain processing specifically includes the following steps:

[0055] S6b, directional temporal subtraction processing

[0056] The one-dimensional high-resolution range image (HRRP) of the scattered echoes of the target under test with varying azimuth is vector-subtracted from the HRRP of a specific scatterer.

[0057] S7b, Time-Domain Processing Echo Reconstruction

[0058] For the target HRRP after vector subtraction, the frequency domain echo signal of the target is reconstructed by one-dimensional fast Fourier transform (FFT).

[0059] Therefore, the present invention employs the one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement, which has the following beneficial effects:

[0060] (1) In actual target RCS measurement, the present invention considers specific scatterers that are either not part of the target component being measured, but are located in the target area and contribute to the scattering measurement echo, such as the target support used in the measurement of the whole target and the carrier used in the measurement of the target component. The echoes of these specific scatterers may be fixed or change with the azimuth angle. Compared with the traditional method, the proposed method is not only applicable to zero Doppler echo suppression with a fixed azimuth angle, but also applicable to scatterer echo suppression with a change in azimuth angle.

[0061] (2) This invention solves the problem that it is difficult to obtain the geometric model of the specific scatterer that generates complex scattered echoes that affect the accuracy of target RCS measurement. The proposed method does not require the auxiliary information of the geometric model of the specific scatterer. The two-dimensional position parameters of the target can be detected and identified in the two-dimensional inverse synthetic aperture radar (ISAR) image through inverse projection imaging. Based on the information of the two-dimensional position parameters of the specific scatterer, the one-dimensional scattered echo of the target that changes with the azimuth can be detected and identified one-way. Compared with the traditional method, the proposed method overcomes the limitation that the extraction of the echo of the specific scatterer must rely on the auxiliary information of the geometric model.

[0062] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0063] Figure 1 The background technology of the one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement of this invention relates to the geometric relationship of target RCS measurement.

[0064] Figure 2 This is a flowchart of a one-dimensional processing method for an embodiment of the radar cross section measurement method for suppressing echoes from specific scatterers in the present invention.

[0065] Figure 3 This is a one-dimensional processing method embodiment for suppressing echoes from specific scatterers in radar cross section measurement of the present invention. The target echo data is contaminated by echoes from specific scatterers, wherein (a) is data domain echo data that varies with frequency and azimuth angle, and (b) is a time domain one-dimensional high-resolution range profile (HRRP) sequence.

[0066] Figure 4 This is a one-dimensional processing method embodiment of the radar cross section measurement of the present invention for suppressing the echo of a specific scatterer. The target echo data after specific scatterer suppression is as follows: (a) is the data domain echo data that varies with frequency and azimuth angle, and (b) is the time domain one-dimensional high-resolution range profile HRRP sequence.

[0067] Figure 5 This is an embodiment of the one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement of the present invention. The uncontaminated target echo data is shown in (a), which is the data domain echo data that varies with frequency and azimuth angle, and (b) is the time domain one-dimensional high-resolution range profile (HRRP) sequence. Detailed Implementation

[0068] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0069] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0070] This invention provides a one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section (RCS) measurements. This method extracts and suppresses echo data from specific scatterers using one-dimensional high-resolution range profile (HRRP) trajectories and filtered inverse projection two-dimensional inverse synthetic aperture radar (ISAR) imaging, without requiring geometric model information of the target. It can extract and suppress both zero-Doppler echo signals that are invariant to azimuth and echo signals that vary with azimuth.

[0071] Among them, a specific scatterer refers to a scattering structure that may or may not belong to the target component being measured, but is located in the target area and contributes to the scattering measurement echo, such as a target support used in the measurement of the whole target machine, or a carrier used in the measurement of the target component.

[0072] Specific scatterer echo suppression refers to the suppression of echoes from specific scatterers (target support, carrier) that are mixed with the target's scattered echoes during the RCS measurement of the target whole machine or target component. Only by eliminating these stray echoes can the accurate measurement of the target's RCS be obtained.

[0073] like Figure 2 As shown, the method proposed in this invention includes two technical solutions, namely:

[0074] (1) A one-dimensional frequency domain processing method for suppressing echoes from specific scatterers in radar cross section (RCS) measurement;

[0075] (2) One-dimensional time-domain processing method for suppressing echoes from specific scatterers in radar cross section (RCS) measurement.

[0076] Example 1

[0077] A one-dimensional frequency domain processing method for suppressing echoes from specific scatterers in radar cross section measurement includes the following steps:

[0078] S1. Acquisition of raw measurement data and pulse compression of target omnidirectional scattered echoes, specifically:

[0079] A 360° omnidirectional rotation measurement of the target is performed to obtain raw measurement data of the amplitude and phase of the scattered echo that varies with frequency and azimuth angle. A one-dimensional high-resolution range profile (HRRP) of the target scattered echo that varies with azimuth is obtained by pulse compression.

[0080] S2, Filtered-Inverse Projection Two-Dimensional Inverse Synthetic Aperture Radar (ISAR) Imaging, specifically:

[0081] The one-dimensional high-resolution range image HRRP obtained in step S1 is back-projected to achieve two-dimensional inverse synthetic aperture radar (ISAR) imaging of the target.

[0082] S3. Detection and identification of two-dimensional position parameters of specific scatterers, specifically:

[0083] In the target two-dimensional inverse synthetic aperture radar (ISAR) image, specific scatterers are detected and identified to determine the precise two-dimensional position parameters of the specific scatterers.

[0084] S4. HRRP trajectory detection and recognition of radial distance per azimuth for specific scatterers, specifically:

[0085] Based on the information assistance of the two-dimensional position parameters of a specific scatterer, the one-dimensional high-resolution range image (HRRP) of the target's scattering echo, which varies with azimuth, is detected and identified azimuth-wise. That is, at each radar observation azimuth angle, the coordinate position of the corresponding reflection point on the two-dimensional image of the specific scatterer is calculated, and the radial distance of the reflection point is calculated according to the projection relationship of the observation azimuth angle, so as to obtain the trajectory parameters of the one-dimensional high-resolution range image (HRRP) of the specific scatterer that varies with azimuth.

[0086] S5. Specific scatterer azimuth echo extraction, specifically:

[0087] The HRRP trajectory of a one-dimensional high-resolution range profile along a specific scatterer varies with azimuth, and the amplitude and phase information of the HRRP of the specific scatterer are extracted based on the maximum probability statistical method.

[0088] S6a, Frequency Domain Processing and Echo Reconstruction

[0089] Based on the complex amplitude and radial distance of the specific scatterer HRRP extracted in step S5, the frequency domain echo signal of the specific scatterer is reconstructed.

[0090] S7a, Subtraction of data domains by orientation

[0091] For frequency domain scattered echo data in each azimuth, a phasor subtraction process is performed between the original target measurement data and the estimated data of a specific scatterer.

[0092] S8a Finally, target scattering echo measurement data varying with frequency and azimuth are obtained for subsequent target imaging, scattering analysis, and other processing.

[0093] Example 2

[0094] A one-dimensional time-domain processing method for suppressing echoes from specific scatterers in radar cross section measurement includes the following steps:

[0095] S1. Acquisition of raw measurement data and pulse compression of target omnidirectional scattered echoes, specifically:

[0096] A 360° omnidirectional rotation measurement of the target is performed to obtain raw measurement data of the amplitude and phase of the scattered echo that varies with frequency and azimuth angle. A one-dimensional high-resolution range profile (HRRP) of the target scattered echo that varies with azimuth is obtained by pulse compression.

[0097] S2, Filtered-Inverse Projection Two-Dimensional Inverse Synthetic Aperture Radar (ISAR) Imaging, specifically:

[0098] The one-dimensional high-resolution range image HRRP obtained in step S1 is back-projected to achieve two-dimensional inverse synthetic aperture radar (ISAR) imaging of the target.

[0099] S3. Detection and identification of two-dimensional position parameters of specific scatterers, specifically:

[0100] In the target two-dimensional inverse synthetic aperture radar (ISAR) image, specific scatterers are detected and identified to determine the precise two-dimensional position parameters of the specific scatterers.

[0101] S4. HRRP trajectory detection and recognition of radial distance per azimuth for specific scatterers, specifically:

[0102] Based on the information assistance of the two-dimensional position parameters of a specific scatterer, the one-dimensional high-resolution range image (HRRP) of the target's scattering echo, which varies with azimuth, is detected and identified azimuth-wise. That is, at each radar observation azimuth angle, the coordinate position of the corresponding reflection point on the two-dimensional image of the specific scatterer is calculated, and the radial distance of the reflection point is calculated according to the projection relationship of the observation azimuth angle, so as to obtain the trajectory parameters of the one-dimensional high-resolution range image (HRRP) of the specific scatterer that varies with azimuth.

[0103] S5. Specific scatterer azimuth echo extraction, specifically:

[0104] The HRRP trajectory of a one-dimensional high-resolution range profile along a specific scatterer varies with azimuth, and the amplitude and phase information of the HRRP of the specific scatterer are extracted based on the maximum probability statistical method.

[0105] S6b, directional temporal subtraction processing

[0106] The one-dimensional high-resolution range image (HRRP) of the scattered echoes of the target under test with varying azimuth is vector-subtracted from the HRRP of a specific scatterer.

[0107] S7b, Time-Domain Processing Echo Reconstruction

[0108] For the target HRRP after vector subtraction, the frequency domain echo signal of the target is reconstructed by one-dimensional fast Fourier transform (FFT).

[0109] S8b Finally, target scattering echo measurement data varying with frequency and azimuth are obtained for subsequent target imaging, scattering analysis, and other processing.

[0110] The technical effects of the present invention can be further illustrated by the following embodiments.

[0111] The data used in this embodiment is aircraft target simulation data obtained through electromagnetic calculations using the method of moments. The frequency sampling is 4.5–5.5 GHz, the step frequency is 5 MHz, the azimuth angle sampling is -180°–180°, and the step angle is 0.06°. According to… Figure 2 The flowchart shown illustrates a one-dimensional processing method for suppressing echoes from specific scatterers, which processes simulation data.

[0112] like Figure 3 (b) It can be seen that the three sine and cosine curves with stronger amplitudes are the radial distance change trajectories of the scattering center generated by the echo of a specific scatterer.

[0113] This embodiment uses a one-dimensional frequency domain processing method for suppressing echoes from specific scatterers in RCS measurement as an example to demonstrate and explain the processing results. Time domain processing has a similar implementation method, except that the echo subtraction and reconstruction processing of specific scatterers are both completed in the time domain, and the mutual transformation between the data domain and the time domain is achieved by performing a fast inverse Fourier transform (data domain to time domain) or a fast Fourier transform (time domain to data domain).

[0114] Figure 4 The figure shows the suppression using the method proposed in this invention. Figure 3 The processing results of the echoes from specific scatterers show that the echoes from those specific scatterers are significantly suppressed. (Compared to...) Figure 5 Compared with the uncontaminated echo data of the target under test, the two show good consistency.

[0115] Therefore, this invention employs the one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section (RCS) measurements. Based on the joint processing of the one-dimensional high-resolution range profile (HRRP) trajectory of the echo data from a specific scatterer after pulse compression in target RCS measurements and the auxiliary information from filtered inverse projection two-dimensional inverse synthetic aperture radar (ISAR) imaging, it achieves the detection and identification of the position parameters of the specific scatterer. It extracts the HRRP of the specific scatterer based on the maximum probability statistical method, and performs echo data reconstruction and phasor subtraction processing on the specific scatterer in the frequency or time domain to suppress the echoes from the specific scatterer. In RCS measurements of the entire target or target components, this invention can effectively suppress the echoes from specific scatterers (target supports, carriers) that are mixed with the target's scattered echoes, thereby improving the accuracy of target RCS measurements.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement, characterized in that, Includes the following steps: S1. Acquisition of raw measurement data of target omnidirectional scattered echo and pulse compression; S2, Filter-Inverse Projection Two-Dimensional Inverse Synthetic Aperture Radar (ISAR) Imaging; S3. Detection and identification of two-dimensional position parameters of specific scatterers; S4. Detection and recognition of HRRP trajectory of radial distance per azimuth of a specific scatterer in one-dimensional high-resolution range image; S5. Azimuth-by-azimuth echo extraction of specific scatterers; S6. After performing one-dimensional frequency domain processing or one-dimensional time domain processing, obtain the target scattered echo data that varies with frequency and azimuth. Step S4 is as follows: Based on the information assistance of the two-dimensional position parameters of a specific scatterer, the one-dimensional high-resolution range image (HRRP) of the target's scattering echo, which varies with azimuth, is detected and identified azimuth-wise. That is, at each radar observation azimuth angle, the coordinate position of the corresponding reflection point on the two-dimensional image of the specific scatterer is calculated, and the radial distance of the reflection point is calculated according to the projection relationship of the observation azimuth angle, so as to obtain the trajectory parameters of the one-dimensional high-resolution range image (HRRP) of the specific scatterer that varies with azimuth.

2. The one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement according to claim 1, characterized in that, The specific scatterer refers to a scattering structure located in the target region that contributes to the scattering measurement echo.

3. The one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement according to claim 2, characterized in that, Step S1 is as follows: A 360° omnidirectional rotation measurement of the target is performed to obtain raw measurement data of the amplitude and phase of the scattered echo that varies with frequency and azimuth angle. A one-dimensional high-resolution range profile (HRRP) of the target scattered echo that varies with azimuth is obtained by pulse compression.

4. The one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement according to claim 3, characterized in that, Step S2 is as follows: The one-dimensional high-resolution range image HRRP obtained in step S1 is back-projected to achieve two-dimensional inverse synthetic aperture radar (ISAR) imaging of the target.

5. The one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement according to claim 4, characterized in that, Step S3 is as follows: In the target two-dimensional inverse synthetic aperture radar (ISAR) image, specific scatterers are detected and identified to determine the precise two-dimensional position parameters of the specific scatterers.

6. The one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement according to claim 5, characterized in that, Step S5 is as follows: The HRRP trajectory of a one-dimensional high-resolution range profile along a specific scatterer varies with azimuth, and the amplitude and phase information of the HRRP of the specific scatterer are extracted based on the maximum probability statistical method.

7. The one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement according to claim 6, characterized in that, In step S6, the one-dimensional frequency domain processing specifically includes the following steps: S6a, Frequency Domain Processing and Echo Reconstruction Based on the complex amplitude and radial distance of the specific scatterer HRRP extracted in step S5, the frequency domain echo signal of the specific scatterer is reconstructed. S7a, Subtraction of data domains by orientation For frequency domain scattered echo data in each azimuth, a phasor subtraction process is performed between the original target measurement data and the estimated data of a specific scatterer.

8. The one-dimensional processing method for suppressing echoes from specific scatterers in radar cross section measurement according to claim 6, characterized in that, In step S6, the one-dimensional time domain processing specifically includes the following steps: S6b, directional temporal subtraction processing The one-dimensional high-resolution range image (HRRP) of the scattered echoes of the target under test with varying azimuth is vector-subtracted from the HRRP of a specific scatterer. S7b, Time-Domain Processing Echo Reconstruction For the target HRRP after vector subtraction, the frequency domain echo signal of the target is reconstructed by one-dimensional fast Fourier transform (FFT).

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