Target radar cross section test method and verification method thereof

Abstract

The application provides a target radar cross section test method and a verification method thereof, and relates to the technical field of radar stealth test. The test method comprises the following steps: obtaining an RCS amplitude curve and an RCS phase curve of a carrier; obtaining the RCS amplitude curve and the RCS phase curve of a low-scattering target and the carrier; correcting the RCS amplitude and the RCS phase of the low-scattering target and the carrier; and obtaining RCS test data of the low-scattering target through a carrier vector cancellation method. The verification method is used for verifying the effectiveness of the target radar cross section test method. The target radar cross section test method solves the problems of inaccurate cancellation and large evaluation error caused by inconsistent placement postures of the low-scattering target and the carrier.

Description

Technical Field

[0001] This invention relates to the field of radar stealth testing technology, and in particular to a method for testing the radar cross section of a target and its verification method. Background Technology

[0002] With the development of stealth technology, the stealth performance of low-observable weapon platforms such as stealth aircraft, stealth ships, and stealth missiles is becoming increasingly sophisticated, placing higher demands on the stealth performance of their components and skin surface equipment systems (i.e., stealth components). During the design and development of stealth components, it is necessary to continuously measure and evaluate the scattering characteristics of low-scattering targets. Therefore, effectively and accurately assessing the stealth performance of stealth components is of paramount importance.

[0003] Currently, the conventional testing method is to first design a stealth carrier that meets the low-scattering requirements, and the carrier's RCS must be an order of magnitude lower than that of the low-scattering target. Then, the low-scattering target is installed on the stealth carrier, and the RCS is evaluated using the carrier vector cancellation method. Specifically, the carrier vector cancellation method requires first testing the RCS of the stealth carrier, then installing the low-scattering target on the stealth carrier for RCS testing, and finally using the carrier-based vector cancellation method to process the two sets of RCS data to evaluate the RCS performance of the test piece.

[0004] However, in the two test states of testing the RCS of the carrier and testing the RCS of the low-scattering target, the low-scattering target's orientation is inconsistent with that of the stealth carrier, and there are positional and azimuth angle differences between the two, which leads to phase shift. If the phase can be corrected, the accuracy of carrier cancellation will be improved, thereby improving the accuracy of RCS test results. Summary of the Invention

[0005] To address the above issues, this invention provides a target radar cross section (RCS) testing method and its verification method. This method can correct the phase shift caused by the inconsistency between the placement attitude of the low-scattering target and the stealth carrier, as well as the difference in position and azimuth angle between the two. This improves the accuracy of carrier cancellation and thus enhances the accuracy of RCS test results.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for testing the radar cross section of a target, which mainly includes the following steps:

[0008] Step S1: Test and obtain the RCS amplitude curve and RCS phase curve of the carrier;

[0009] Step S2: Test and obtain the RCS amplitude curves and RCS phase curves of the low-scattering target and carrier;

[0010] Step S3: Correct the RCS amplitude and RCS phase of the low-scattering target and carrier;

[0011] Step S4: Obtain the RCS test results of the low-scattering target using the carrier vector cancellation method.

[0012] In some embodiments of the present invention, step S3 includes the following steps:

[0013] Step S31: Let the azimuth angle corresponding to the typical characteristic RCS peak of the carrier in step S1 be... Let the azimuth angle corresponding to the typical characteristic RCS peak of the low-scattering target and carrier in step S2 be . The difference in azimuth angle between the placement of the target in step S1 and step S2 is:

[0014] Let the center coordinates of the upper surface of the carrier be (x, y) = (0, 0);

[0015] Step S32: Assuming the center coordinates of the low-scattering target are (x1, y1), its phase correction is:

[0016]

[0017] Where λ represents the current RCS test wavelength; θ represents the azimuth angle; θ represents the elevation angle. In anechoic chamber testing, θ is taken as 90°.

[0018] Step S33: For different azimuth angles, the corrected phase is... Where φ0 is the phase before correction;

[0019] Step S34: Traverse the specified azimuth region. The RCS phase difference between the corrected low-scattering target and the carrier and the carrier's RCS phase is:

[0020]

[0021] in, For the carrier in azimuth angle The RCS phase obtained from the test;

[0022] Based on the different center coordinates (x) of the low-scattering target i y i Different phase differences were obtained.

[0023] Step S35: Obtain the optimal solution (x) through optimization algorithm. n y n );

[0024] Step S36: Based on the optimal solution (xn, yn), perform phase correction on all azimuth angles of the RCS of the low-scattering target and the carrier according to step S33 above, to obtain the RCS phase of the low-scattering target and the carrier.

[0025] Step S37: Correct the orientation of the azimuth angle of the target placement in steps S1 and S2 using the following formula:

[0026]

[0027]

[0028] in, The corrected azimuth angle The RCS amplitude corresponding to low-scattering targets and carriers; The corrected azimuth angle The RCS phase corresponding to low-scattering targets and carriers; The azimuth angle obtained from the test The corresponding RCS amplitudes of low-scattering targets and carriers; The azimuth angle obtained in step S36 is corrected. The corresponding RCS phase of the low-scattering target and carrier.

[0029] In some embodiments of the present invention, in step S4, the RCS test results of the low-scattering target are obtained by the following formula:

[0030]

[0031]

[0032] in, Represents the complex RCS of a low-scattering target; σ 目标 For low-scattering targets, the RCS amplitude is σ. 目标+载体 The corrected RCS amplitude for low-scattering targets and carriers; φ 目标+载体 The corrected RCS phase for low-scattering targets and carriers; σ 载体 and φ 载体 represents the scalar RCS amplitude and phase of the carrier, respectively; j is a constant.

[0033] In some embodiments of the present invention, in step S35, the optimal solution (x) is obtained by traversal or least squares method. n y n ).

[0034] In some embodiments of the present invention, in step S2, the low-scattering target is mounted on the carrier, and the pitch angle and / or roll angle attitude difference between the low-scattering target and the carrier is no greater than ±0.1°.

[0035] Secondly, the present invention provides a verification method for a target radar cross section testing method, which mainly includes the following steps:

[0036] Step F1: Obtain the RCS amplitude curve and RCS phase curve of the first theoretical model; the first theoretical model includes the carrier.

[0037] Step F2: Set the low-scattering target on the first theoretical model; use the low-scattering target and the first theoretical model together as the second theoretical model;

[0038] Step F3: Simulate to obtain the RCS amplitude curve and RCS phase curve of the second theoretical model;

[0039] Step F4: Obtain the RCS amplitude curve of the low-scattering target in the second theoretical model using the carrier vector cancellation method;

[0040] Step F5: First, rotate the second theoretical model in azimuth and translate its position to obtain the third theoretical model. Then, simulate and obtain the RCS amplitude curve and RCS phase curve of the third theoretical model.

[0041] Step F6: Correct the RCS amplitude and RCS phase of the third theoretical model;

[0042] Step F7: Obtain the RCS amplitude curve of the low-scattering target in the third theoretical model using the carrier vector cancellation method;

[0043] Step F8: Compare and verify the RCS amplitude curve of the low-scattering target in the third theoretical model with the RCS amplitude curve of the low-scattering target in the second theoretical model.

[0044] In some embodiments of the present invention, step F6 includes the following steps:

[0045] Step F61: Let the azimuth angle corresponding to the typical characteristic RCS peak of the carrier in step F1 be... Let the azimuth angle corresponding to the typical characteristic RCS peak of the low-scattering target and carrier in step F5 be . The difference in azimuth angle between the target placement in steps F1 and F5 is:

[0046] Let the center coordinates of the upper surface of the carrier be (x, y) = (0, 0);

[0047] In step F62, after azimuthally shifting the low-scattering target and carrier in the third theoretical model in step F5, the center coordinates of the low-scattering target become (x1, y1), and its phase correction is:

[0048]

[0049] Where λ represents the current RCS test wavelength; θ represents the azimuth angle; θ represents the elevation angle.

[0050] Step F63: For different azimuth angles, the corrected phase is... Where φ0 is the phase before correction;

[0051] Step F64: Traverse the specified azimuth region. The RCS phase difference between the corrected low-scattering target and the carrier and the carrier's RCS phase is:

[0052]

[0053] in, For the carrier in azimuth angle The RCS phase obtained from the test;

[0054] Based on the different center coordinates (x) of the low-scattering target i y i Different phase differences were obtained.

[0055] Step F65: Through optimization algorithm, obtain the optimal solution (x) for the center coordinates of the low-scattering target. n y n );

[0056] Step F66, based on the optimal solution (x) n y n For all azimuth angles of the RCS of the low-scattering target and the carrier in the third theoretical model, phase correction is performed according to step F63 above to obtain the RCS phase of the slot and the carrier.

[0057] Step F67: Correct the orientation of the azimuth angle of the target being measured in steps F1 and F5 using the following formula:

[0058]

[0059]

[0060] in, The corrected azimuth angle The RCS amplitude corresponding to low-scattering targets and carriers; The corrected azimuth angle The RCS phase corresponding to low-scattering targets and carriers; The azimuth angle obtained from the test The corresponding RCS amplitudes of low-scattering targets and carriers; φ1(φ-φ c The azimuth angle obtained in step F66 is the corrected azimuth angle. The corresponding RCS phase of the low-scattering target and carrier.

[0061] In some embodiments of the present invention, in step F65, the optimal solution (x) is obtained by traversal or least squares method. n y n ).

[0062] In some embodiments of the present invention, in step F2, a slender slit is opened at the center of the upper surface of the carrier in the first theoretical model, and the slit is used as a low-scattering target.

[0063] In some embodiments of the present invention, in step F7, the RCS result of the low-scattering target is obtained by the following formula:

[0064]

[0065]

[0066] in, The gap vector is RCS; σ 缝隙 σ represents the RCS amplitude of the gap. 缝隙+载体 The RCS amplitude after correction for gaps and carrier; φ 缝隙+载体 The RCS phase is corrected for the gap and the carrier; σ 载体 φ is the scalar RCS amplitude of the carrier. 载体 denoted as the scalar RCS phase of the carrier; j is a constant.

[0067] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0068] ① The target radar cross section test method is based on the carrier vector cancellation method. By correcting the amplitude and phase of the test results, it solves the technical problems such as the amplitude and phase mismatch caused by the inconsistent placement attitude of the low-scattering target and the carrier, which leads to inaccurate cancellation and large evaluation error. Thus, it provides technical support and implementation means for the engineering application of the carrier vector cancellation method.

[0069] ② Conventional testing methods require the carrier RCS to be one order of magnitude lower than the target RCS. However, using the target radar cross section testing method provided by this invention, the carrier RCS can be higher than the RCS requirement for low-scattering targets. In other words, this invention reduces the requirements for carrier RCS performance in the evaluation of low-scattering target RCS.

[0070] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0071] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0072] Figure 1 A schematic diagram showing that the pitch angle difference between the low-scattering target (not shown in the figure) and the carrier provided in Example 1 is no greater than ±0.1°;

[0073] Figure 2 A schematic diagram of the gap and carrier provided in Example 2;

[0074] Figure 3 A schematic diagram showing the RCS amplitude curve of the carrier in the first theoretical model provided for Example 2 and the RCS amplitude curves of the gap and the carrier in the third theoretical model;

[0075] Figure 4 A schematic diagram of the RCS phase curve of the carrier in the first theoretical model provided for Example 2 and the RCS phase curve of the gap and the carrier in the third theoretical model;

[0076] Figure 5 This is a schematic diagram showing the comparison between the RCS amplitude curve of the gap in the corrected and canceled third theoretical model and the RCS amplitude curve of the gap in the canceled second theoretical model, as provided in Example 2. Detailed Implementation

[0077] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention.

[0078] In the description of the embodiments of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0079] In the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0080] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0081] Example 1

[0082] This embodiment provides a method for testing the radar cross section of a target, which mainly includes the following steps:

[0083] Step S1: Obtain the RCS amplitude curve and RCS phase (scattered field phase) curve of the carrier, including the following steps:

[0084] Step S11: Place the carrier in the middle of the turntable (not shown in the figure) so that the rotation axis of the turntable coincides with or is substantially coincident with the center of gravity of the carrier.

[0085] Step S12: Test and obtain the RCS of the carrier within a specified azimuth angle range (e.g., the azimuth angles of four different intervals: forward, left, right and backward) to obtain the RCS amplitude curve and RCS phase curve of the carrier.

[0086] Step S2: Obtain the RCS amplitude curves and RCS phase curves of the low-scattering target and carrier, including the following steps:

[0087] Step S21: Mount the low-scattering target on the carrier; please refer to... Figure 1 and Figure 2 The pitch and roll angles of the low-scattering target and the carrier in step S11 are not more than ±0.1° apart, and the corresponding angles can be accurately measured by instruments such as angle measuring instruments.

[0088] Step S22: Test the RCS of the low-scattering target and the carrier within the specified azimuth angle range, and obtain the RCS amplitude curve and RCS phase curve of the low-scattering target and the carrier.

[0089] Step S3: Correct the RCS amplitude and RCS phase of the low-scattering target and carrier;

[0090] When correcting the RCS amplitude and RCS phase of the low-scattering target and the carrier, since the low-scattering target is fixed on the turntable, it is assumed that the z-direction of the low-scattering target and the carrier are consistent, so no correction is made for the z-direction of the low-scattering target. In the two tests in steps S12 and S22, due to the different placement position and azimuth of the target under test, there is an optical path difference between the radar wave and the target under test in the two tests, which leads to phase deviation. Therefore, it is necessary to correct the x and y directions and the azimuth at this position. Specifically, the correction of the RCS amplitude and RCS phase of the low-scattering target and the carrier includes the following steps:

[0091] Step S31: Let the azimuth angle corresponding to the typical characteristic RCS peak of the carrier in step S12 be... The azimuth angle corresponding to the typical characteristic RCS peak of low-scattering targets and carriers in step S22 is: The difference in azimuth angle between the target (low-scattering target and carrier, or carrier) placed in steps S12 and S22 is:

[0092] Let the center coordinates of the upper surface of the carrier be (x, y) = (0, 0).

[0093] Step S32: Assuming the center coordinates of the low-scattering target are (x1, y1), its phase correction is:

[0094]

[0095] Where λ represents the current RCS test wavelength; Let θ represent the azimuth angle; θ represents the elevation angle. In anechoic chamber testing, θ is taken as 90°. Therefore, the above formula can be simplified to:

[0096]

[0097] Step S33: For different azimuth angles, the corrected phase is... Where φ0 is the phase before correction.

[0098] Step S34: Traverse the specified azimuth region. The difference between the corrected "RCS phase of low-scattering target and carrier" and "RCS phase of carrier" is:

[0099]

[0100] in, The RCS phase is obtained by measuring the carrier at the azimuth angle φ.

[0101] Based on the different center coordinates (x) of the low-scattering target i y i Different phase differences can be obtained.

[0102] Step S35: By using optimization algorithms such as traversal or least squares, the optimal solution (x) can be obtained. n y n This ensures that the RCS phase of the "low-scattering target and carrier" differs from the RCS phase of the "carrier" within a specified azimuth angle range.

[0103] The specified azimuth range mentioned above refers to the range of azimuth angles that the user specifies based on the characteristics of the target being measured, and the specified azimuth range must be smaller than the test azimuth range. For example, the test azimuth range is ±90°, and the specified azimuth range is ±10°.

[0104] Step S36: Based on the optimal solution (x)n y n For all azimuth angles of the RCS of the low-scattering target and the carrier, phase correction is performed according to step S33 above to obtain the RCS phase of the low-scattering target and the carrier.

[0105] Step S37: Correct the orientation of the azimuth angle of the target placement in steps S12 and S22 using the following formula:

[0106]

[0107]

[0108] in, The corrected azimuth angle The RCS amplitude corresponding to low-scattering targets and carriers; The corrected azimuth angle The RCS phase corresponding to low-scattering targets and carriers; The azimuth angle obtained from the test The corresponding RCS amplitudes of low-scattering targets and carriers; The azimuth angle obtained in step S36 is corrected. The corresponding RCS phase of the low-scattering target and carrier.

[0109] After correcting the RCS phase of the "low-scattering target and carrier" through steps S31 to S37, the placement attitude (center position, azimuth direction) of the "low-scattering target and carrier" and the "carrier" can be corrected, that is, the placement attitude of the target being measured in steps S12 and S22 is consistent.

[0110] Step S4: Obtain the RCS test results of the low-scattering target using the carrier vector cancellation method; the carrier vector cancellation method yields the RCS test results of the low-scattering target using the following formula:

[0111]

[0112]

[0113] in, Represents the complex RCS of a low-scattering target; σ 目标 For low-scattering targets, the RCS amplitude is σ. 目标+载体 The corrected RCS amplitude for low-scattering targets and carriers; φ 目标+载体 The corrected RCS phase for low-scattering targets and carriers; σ 载体 and φ 载体 represents the scalar RCS amplitude and phase of the carrier, respectively; j is a constant.

[0114] Example 2

[0115] Please refer to Figures 1-5 This embodiment provides a verification method for the above-mentioned target radar cross section testing method, which mainly includes the following steps:

[0116] Step F1: Obtain the RCS amplitude curve and RCS phase curve of the carrier in the first theoretical model, including the following steps:

[0117] Step F11: Model the carrier to obtain the first theoretical model mentioned above;

[0118] Please refer to Figure 1 and Figure 2 In the first theoretical model, the carrier is a flat shape with a central outward convexity, and the carrier includes two symmetrically arranged frustums.

[0119] Step F12: Simulate the RCS of the carrier in the first theoretical model within a specified azimuth range (e.g., the azimuth angles of four different intervals: forward, left, right, and backward) to obtain the RCS amplitude curve and RCS phase curve of the carrier in the first theoretical model.

[0120] Step F2: In the first theoretical model, a slender slit is made at the center of the upper surface of the carrier, and the slit is used as a low-scattering target, thus setting the low-scattering target on the carrier; the slit and the first theoretical model are used together as the second theoretical model; the pitch angle and roll angle attitude difference between the slit and the carrier are 0.

[0121] Step F3: Simulate and obtain the RCS amplitude curves and RCS phase curves of the gap and the carrier in the second theoretical model.

[0122] Step F4: Obtain the RCS of the gap in the second theoretical model through the carrier vector cancellation method, thereby obtaining the RCS amplitude curve of the gap in the second theoretical model.

[0123] Step F5: First, rotate the azimuth angle and translate the position of the gap and the carrier in the second theoretical model to obtain the third theoretical model. Then, obtain the RCS amplitude curve and RCS phase curve of the gap and the carrier in the third theoretical model.

[0124] In step F5, when rotating the gap and the carrier in the second theoretical model in azimuth and translating their positions, the second theoretical model is rotated by 5° in the azimuth plane and translated by (50mm, 50mm, 0mm) to simulate the actual test conditions.

[0125] The third theoretical model introduces azimuth rotation and position offset to simulate actual test conditions.

[0126] In step F5, when obtaining the RCS amplitude curves and RCS phase curves of the gap and the carrier in the third theoretical model, the following steps are included:

[0127] Simulate the RCS of the gap and the carrier within a specified azimuth range in the third theoretical model, and obtain the RCS amplitude curve and RCS phase curve of the gap and the carrier in the third theoretical model.

[0128] Please refer to Figure 3 ,exist Figure 3 In the figure, the vertical axis is in dBsm. A comparison of the RCS amplitude curves of the gap and carrier in the third theoretical model with the RCS amplitude curve of the carrier in the first theoretical model shows that the difference between the two RCS amplitude curves is within 2 dB, and less than 0.1 dB over most angle ranges. Please refer to... Figure 4 ,exist Figure 4 In the figure, the vertical axis represents the phase, and the unit is degrees. By comparing the RCS phase curves of the gap and the carrier in the third theoretical model with the RCS phase curve of the carrier in the first theoretical model, it can be seen that the phases of the two have changed significantly. If the phase of the gap and the carrier in the third theoretical model is corrected, it will help to accurately perform subsequent cancellation (i.e., step F7 below).

[0129] Step F6: Correct the RCS amplitude and RCS phase of the gap and the carrier;

[0130] When correcting the RCS amplitude and RCS phase of the slot and the carrier, since the slot (low-scattering target) is fixed on the turntable, the z-direction of the slot and the carrier is assumed to be consistent, so no correction is made for the z-direction of the slot. In the two tests in steps F12 and F5, the optical path difference between the radar wave and the target is due to the different placement positions of the target, resulting in phase deviation. Therefore, it is necessary to correct the x and y directions and azimuth angle at this position. Specifically, the correction of the RCS amplitude and RCS phase of the slot and the carrier includes the following steps:

[0131] Step F61: Let the azimuth angle corresponding to the typical characteristic RCS peak of the carrier in step F12 be... Let the azimuth angle corresponding to the peak value of the typical characteristic RCS of the gap and the carrier in step F5 be . The difference in azimuth angle between the target (slit and carrier, or carrier) placed in steps F12 and F5 is:

[0132] Let the center coordinates of the upper surface of the carrier in the first theoretical model be (x, y) = (0, 0).

[0133] In step F62, after translating the gap and carrier in the third theoretical model in step F5, the center coordinates of the gap become (x1, y1), and its phase correction is:

[0134]

[0135] Where λ represents the current RCS test wavelength; θ represents the azimuth angle; θ represents the elevation angle.

[0136] Step F63: For different azimuth angles, the corrected phase is... Where φ0 is the phase before correction.

[0137] Step F64: Traverse the specified azimuth region. The RCS phase difference between the corrected gap and the carrier and the carrier's RCS phase is:

[0138]

[0139] in, For the carrier in azimuth angle The RCS phase obtained from the test;

[0140] Based on the different center coordinates (x) of the gap i y i Different phase differences can be obtained.

[0141] Step F65: By using optimization algorithms such as traversal or least squares, the optimal solution (x) for the gap center coordinates can be obtained. n y n This ensures that the RCS phase of the gap and the carrier differs from the RCS phase of the carrier within a specified azimuth range.

[0142] The specified azimuth range mentioned above refers to the range of azimuth angles that the user specifies based on the characteristics of the target being measured, and the specified azimuth range must be smaller than the test azimuth range. For example, the test azimuth range is ±90°, and the specified azimuth range is ±10°.

[0143] Step F66, based on the optimal solution (x) n y n For all azimuth angles of the RCS of the gap and the carrier in the third theoretical model, phase correction is performed according to step F63 above to obtain the RCS phase of the gap and the carrier.

[0144] Step F67: Correct the orientation of the azimuth angle of the target being measured in steps F12 and F5 using the following formula:

[0145]

[0146]

[0147] in, The corrected azimuth angle The RCS amplitude corresponding to the gap and the carrier; The corrected azimuth angle The RCS phase corresponding to the gap and the carrier; The azimuth angle obtained from the test The corresponding RCS amplitude of the gap and the carrier; The azimuth angle obtained in step F66 is corrected. The corresponding RCS phase of the gap and the carrier.

[0148] After correcting the RCS phase of the "gap and carrier" through steps F61 to F67, the RCS phase of the "gap and carrier" can be made consistent with the placement posture (center position, azimuth direction) of the "carrier", that is, the placement posture of the target being measured in F12 and F5 is made consistent.

[0149] Step F7: Obtain the RCS of the gap in the third theoretical model using the carrier vector cancellation method, thereby obtaining the RCS amplitude curve of the gap in the third theoretical model; the carrier vector cancellation method obtains the RCS result of the gap in the third theoretical model according to the following formula:

[0150]

[0151]

[0152] The gap vector is RCS; σ 缝隙 σ represents the RCS amplitude of the gap. 缝隙+载体 The RCS amplitude after correction for gaps and carrier; φ 缝隙+载体 The RCS phase is corrected for the gap and the carrier; σ 载体 φ is the scalar RCS amplitude of the carrier. 载体 denoted as the scalar RCS phase of the carrier; j is a constant.

[0153] Step F8: Compare the RCS amplitude curve of the gap in the corrected and canceled third theoretical model with the RCS amplitude curve of the gap in the canceled second theoretical model; please refer to... Figure 5 ,exist Figure 5 In the figure, the vertical axis is in dBsm; the comparison curves are highly consistent in the main lobe and first side lobe regions, and the RCS is extremely low (<-65dBsm) in the region around ±90°; although numerical errors lead to a certain loss of accuracy, the comparison results still demonstrate the effectiveness of the target radar cross section testing method provided by this invention.

[0154] Based on the above, it can be seen that the target radar cross section testing method provided by the present invention has at least the following beneficial effects:

[0155] ① The target radar cross section test method is based on the carrier vector cancellation method. By correcting the amplitude and phase of the test results, it solves the technical problems such as the amplitude and phase mismatch caused by the inconsistent placement attitude of the low-scattering target and the carrier, which leads to inaccurate cancellation and large evaluation error. Thus, it provides technical support and implementation means for the engineering application of the carrier vector cancellation method.

[0156] ② Conventional testing methods require the carrier's RCS to be one order of magnitude lower than the target's RCS. However, by using the aforementioned target radar cross section testing method, the carrier's RCS can be lower than the low-scattering target's RCS. In other words, this invention reduces the requirements for the carrier's RCS performance in the evaluation of low-scattering target RCS.

[0157] It should be noted that when the RCS performance of the low-scattering carrier is good, the sensitivity to phase error in the target RCS test will be reduced. The target radar cross section test method can effectively reduce the requirements for the RCS performance of the low-scattering carrier, but it is not without requirements. Specifically, the target radar cross section test method usually requires the carrier RCS to be no more than one order of magnitude higher than the RCS of the low-scattering target, while the conventional method requires the carrier RCS to be one order of magnitude lower than the RCS of the low-scattering target. This is equivalent to reducing the requirements for the carrier RCS performance by two orders of magnitude, or 20 dB.

[0158] ③ Because RCS testing of low-scattering targets and carriers can be performed in all directions (360 degrees), and testing and cancellation processing of low-scattering targets in four different regions (forward, left, right, and backward) can be achieved simultaneously, this invention greatly reduces testing time and cost, improves testing efficiency, and achieves cost reduction and efficiency improvement.

[0159] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Without conflict, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for testing the radar cross section of a target, characterized in that, Includes the following steps: Step S1: Test and obtain the RCS amplitude curve and RCS phase curve of the carrier; Step S2: Test and obtain the RCS amplitude curves and RCS phase curves of the low-scattering target and carrier; Step S3: Correct the RCS amplitude and RCS phase of the low-scattering target and carrier; Step S4: Obtain the RCS test results of the low-scattering target using the carrier vector cancellation method; Step S3 includes the following steps: Step S31: Let the azimuth angle corresponding to the typical characteristic RCS peak of the carrier in step S1 be... Let the azimuth angle corresponding to the typical characteristic RCS peak of the low-scattering target and carrier in step S2 be . The difference in azimuth angle between the placement of the target in step S1 and step S2 is: ; Let the center coordinates of the upper surface of the carrier be (x, y) = (0, 0); Step S32: Assuming the center coordinates of the low-scattering target are (x1, y1), its phase correction is: ， in, Indicates the current RCS test wavelength; Indicates azimuth; Indicates the angle of elevation during darkroom testing. ; Step S33: For different azimuth angles, the corrected phase is... ,in, To correct the previous phase; Step S34: Traverse the specified azimuth region. The RCS phase difference between the corrected low-scattering target and the carrier and the carrier's RCS phase is: ， in, For the carrier in azimuth angle The RCS phase obtained from the test; Based on the different center coordinates (x) of the low-scattering target i y i Different phase differences are obtained. ; Step S35: Obtain the optimal solution (x) through optimization algorithm. n y n ); Step S36: Based on the optimal solution (x) n y n For all azimuth angles of the RCS of the low-scattering target and the carrier, phase correction is performed according to step S33 above to obtain the RCS phase of the low-scattering target and the carrier. ; Step S37: Correct the orientation of the azimuth angle of the target placement in steps S1 and S2 using the following formula: ， ， in, The corrected azimuth angle The RCS amplitude corresponding to low-scattering targets and carriers; The corrected azimuth angle The RCS phase corresponding to low-scattering targets and carriers; The azimuth angle obtained from the test The corresponding RCS amplitudes of low-scattering targets and carriers; The azimuth angle obtained in step S36 is corrected. The corresponding RCS phase of the low-scattering target and carrier.

2. The target radar cross section testing method according to claim 1, characterized in that, In step S4, the RCS test results of the low-scattering target are obtained according to the following formula: ， = ， in, Represents the complex RCS of a low-scattering target; For low-scattering targets, the RCS amplitude is required. The corrected RCS amplitude for low-scattering targets and carriers; The corrected RCS phase for low-scattering targets and carriers; and represents the scalar RCS amplitude and phase of the carrier, respectively; j is a constant.

3. The target radar cross section testing method according to claim 1, characterized in that, In step S35, the optimal solution (x) is obtained by traversal or least squares method. n y n ).

4. The target radar cross section testing method according to any one of claims 1 to 3, characterized in that, In step S2, the low-scattering target is mounted on the carrier, and the pitch and / or roll angle attitude difference between the low-scattering target and the carrier is no greater than ±0.1°.

5. A verification method for a target radar cross section testing method, characterized in that, Includes the following steps: Step F1: Obtain the RCS amplitude curve and RCS phase curve of the first theoretical model; the first theoretical model includes the carrier. Step F2: Set the low-scattering target on the first theoretical model; use the low-scattering target and the first theoretical model together as the second theoretical model; Step F3: Simulate to obtain the RCS amplitude curve and RCS phase curve of the second theoretical model; Step F4: Obtain the RCS amplitude curve of the low-scattering target in the second theoretical model using the carrier vector cancellation method; Step F5: First, rotate the second theoretical model in azimuth and translate its position to obtain the third theoretical model. Then, simulate and obtain the RCS amplitude curve and RCS phase curve of the third theoretical model. Step F6: Correct the RCS amplitude and RCS phase of the third theoretical model; Step F7: Obtain the RCS amplitude curve of the low-scattering target in the third theoretical model using the carrier vector cancellation method; Step F8: Compare and verify the RCS amplitude curve of the low-scattering target in the third theoretical model with the RCS amplitude curve of the low-scattering target in the second theoretical model; Step F6 includes the following steps: Step F61: Let the azimuth angle corresponding to the typical characteristic RCS peak of the carrier in step F1 be... Let the azimuth angle corresponding to the typical characteristic RCS peak of the low-scattering target and carrier in step F5 be . The difference in azimuth angle between the target placement in steps F1 and F5 is: ; Let the center coordinates of the upper surface of the carrier be (x, y) = (0, 0); In step F62, after azimuthally shifting the low-scattering target and carrier in the third theoretical model in step F5, the center coordinates of the low-scattering target become (x1, y1), and its phase correction is: ， in, Indicates the current RCS test wavelength; Indicates azimuth; Indicates the angle of elevation; Step F63: For different azimuth angles, the corrected phase is... ,in, To correct the previous phase; Step F64: Traverse the specified azimuth region. The RCS phase difference between the corrected low-scattering target and the carrier and the carrier's RCS phase is: ， in, For the carrier in azimuth angle The RCS phase obtained from the test; Based on the different center coordinates (x) of the low-scattering target i y i Different phase differences are obtained. ; Step F65: Through optimization algorithm, obtain the optimal solution (x) for the center coordinates of the low-scattering target. n y n ); Step F66, based on the optimal solution (x) n y n For all azimuth angles of the RCS of the low-scattering target and the carrier in the third theoretical model, phase correction is performed according to step F63 above to obtain the RCS phase of the slot and the carrier. ; Step F67: Correct the orientation of the azimuth angle of the target being measured in steps F1 and F5 using the following formula: ， ， in, The corrected azimuth angle The RCS amplitude corresponding to low-scattering targets and carriers; The corrected azimuth angle The RCS phase corresponding to low-scattering targets and carriers; The azimuth angle obtained from the test The corresponding RCS amplitudes of low-scattering targets and carriers; The azimuth angle obtained in step F66 is corrected. The corresponding RCS phase of the low-scattering target and carrier.

6. The verification method for the target radar cross section testing method according to claim 5, characterized in that, In step F65, the optimal solution (x) is obtained by traversal or least squares method. n y n ).

7. The verification method for the target radar cross section testing method according to claim 5 or 6, characterized in that, In step F2, a slender slit is made at the center of the upper surface of the carrier in the first theoretical model, and this slit is used as a low-scattering target.

8. The verification method for the target radar cross section testing method according to claim 7, characterized in that, In step F7, the RCS result of the low-scattering target is obtained by the following formula: ， = ， in, The gap vector is RCS; The RCS amplitude of the gap; The RCS amplitude after correction for gaps and carrier; The RCS phase is corrected for the gap and the carrier; The scalar RCS amplitude of the carrier; denoted as the scalar RCS phase of the carrier; j is a constant.

Images