A method and system for testing the RCS of an aircraft

Abstract

The present invention relates to the technical field of RCS testing, and particularly relates to a method and system for testing the RCS of an aircraft. An embodiment of the present invention provides a method for testing the RCS of an aircraft, including: determining a gain height according to a test distance, a target height, and a test wavelength; controlling the transceiver device to perform RCS testing at different test heights to obtain a plurality of test data; determining a complex weighting coefficient according to the test distance, the gain height, and a plurality of different height values of the aircraft; wherein the height value is the height of any point on the surface and inside of the aircraft from the ground; processing the test data according to the complex weighting coefficient to improve the RCS test accuracy. The present invention provides a method and system for testing the RCS of an aircraft, which can obtain more accurate RCS test data.

Description

Technical Field

[0001] The present invention relates to the technical field of RCS testing, and particularly to a method and system for testing the RCS of an aircraft. Background Art

[0002] When performing RCS testing on an aircraft, the aircraft needs to be set at a fixed height, and a transceiver device is used to transmit radar waves to the aircraft. The radar waves directly emitted to the aircraft are called direct waves. The direct waves are reflected by the aircraft, and the transceiver device receives the radar waves reflected by the aircraft for RCS testing. However, some of the radar waves emitted by the transceiver device will be reflected by the ground, and some of the ground-reflected waves will propagate to the aircraft. The waves that reach the aircraft after being reflected by the ground are called ground-reflected waves, and the ground-reflected waves will interfere with the RCS testing.

[0003] In the related art, in order to avoid the interference of ground-reflected waves on RCS testing, the height of the transceiver device is set according to the test distance and the height of the aircraft, so that interference occurs between the direct wave and the ground-reflected wave, thereby eliminating the interference of the ground-reflected wave, and at the same time, an additional SNR gain of 12 dB can be obtained. However, this method is only effective for targets within a relatively narrow height range. When the pitch angle of the aircraft is large, the height range of the aircraft is much larger than the effective height range of the above method. Therefore, the RCS testing of the aircraft will still be interfered by the ground-reflected waves. Summary of the Invention

[0004] The present invention provides a method and system for testing the RCS of an aircraft, which can obtain more accurate RCS test data.

[0005] An embodiment of the present invention provides a method for testing the RCS of an aircraft, including:

[0006] Determining a gain height according to the test distance, the target height, and the test wavelength; wherein, the test distance is the horizontal distance between the transceiver device and the aircraft, the target height is the height of the aircraft, the gain height is the height at which the direct wave and the ground-reflected wave generate gain interference, the direct wave is the radar wave directly emitted by the transceiver device to the aircraft, and the ground-reflected wave is the radar wave emitted by the transceiver device and reflected by the ground to reach the aircraft;

[0007] Controlling the transceiver device to perform RCS testing at different test heights to obtain a plurality of test data; wherein, the transceiver device is used to transmit and receive radar waves, and the test height is a positive integer multiple of the gain height;

[0008] Determining a complex weighting coefficient according to the test distance, the gain height, and a plurality of different height values of the aircraft; wherein, the height value is the height of any point on the surface and inside of the aircraft from the ground;

[0009] Process the test data according to the complex weighting coefficient to improve the RCS test accuracy.

[0010] In a possible design, the determining the gain height according to the test distance, the target height, and the test wavelength includes:

[0011] Determine the gain height according to the test distance, the target height, and the test wavelength through the antenna height formula;

[0012] The antenna height formula is:

[0013]

[0014] where H1 is the gain height, λ is the test wavelength, R0 is the test distance, and H t is the target height.

[0015] In a possible design, the determining the complex weighting coefficient according to the test distance, the gain height, and multiple different height values of the aircraft includes:

[0016] Determine the amplitude of the complex weighting coefficient according to the test distance, the gain height, and the multiple different height values;

[0017] Determine the phase of the complex weighting coefficient according to the test distance and the gain height;

[0018] Determine the complex weighting coefficient according to the amplitude and the phase.

[0019] In a possible design, the determining the amplitude of the complex weighting coefficient according to the test distance, the gain height, and the height value includes:

[0020] Determine the amplitude of the complex weighting coefficient according to the test distance, the gain height, and the height value through the amplitude formula;

[0021] The amplitude formula is:

[0022] AM = I

[0023] A = [A1, A2,..., A N 1×N ,

[0024]

[0025] ​A is the echo level amplitude, M is the amplitude, I is the constant value of the interference gain in the height direction, N is the total number of RCS tests, n is the nth RCS test, and at the nth RCS test, the test height is n*H1, H1 is the gain height, h is the height value, k is the number of height values, and R0 is the test distance.

[0026] In a possible design, determining the complex weighting coefficient according to the amplitude and the phase includes:

[0027] Determining the complex weighting coefficient according to the amplitude and the phase through a phase formula;

[0028] The phase formula is:

[0029]

[0030]

[0031] Wherein, is the phase, H1 is the gain height, n is the nth RCS test, and at the nth RCS test, the test height is n*H1, λ is the test wavelength, R0 is the test distance, and H t is the target height, and h is the height value.

[0032] In a possible design, determining the complex weighting coefficient according to the amplitude and the phase includes:

[0033] Determining the complex weighting coefficient according to the amplitude and the phase through the following formula:

[0034]

[0035] Wherein, C n is the complex weighting coefficient, n is the nth RCS test, M is the amplitude, is the phase, and j is the imaginary unit.

[0036] In a possible design, processing the test data according to the complex weighting coefficient to improve the RCS test accuracy includes:

[0037] Processing the test data according to the complex weighting coefficient through the following formula to improve the RCS test accuracy:

[0038]

[0039] Wherein, E is the test data, E' is the processed test data, C n is the complex weighting coefficient, and N is the total number of RCS tests.

[0040] In a possible design, the test data is the data of the echo of the aircraft after I / Q adjustment.

[0041] In a second aspect, an embodiment of the present invention provides a system for testing the RCS of an aircraft, which is used to implement the method described in any one of the first aspects, including:

[0042] The transceiver device is used to receive and transmit electromagnetic waves;

[0043] The measurement system is electrically connected to the transceiver device and is used to process the echo data received by the transceiver device;

[0044] The aircraft is used to receive the reflected electromagnetic wave;

[0045] The support device is used to support the aircraft and adjust the pitch angle of the aircraft.

[0046] In a possible design, the support device is a turntable or a metal bracket with a rotating top.

[0047] Compared with the prior art, the present invention has at least the following beneficial effects:

[0048] In this embodiment, first, the gain height that can cause the direct wave and the ground reflected wave to interfere is determined according to the test distance, the target height, and the test wavelength. Fixing the transceiver device at the gain height can make the direct wave and the transmitted wave interfere, improving the accuracy of the test data. However, the method of measuring once can only have an obvious effect in a relatively narrow range above and below the target height. When the pitch angle of the aircraft is large, the effect of gain interference on the part where the aircraft deviates upward or downward from the target height by a large amount is not obvious. Measuring the transceiver device multiple times at multiple positions that are multiples of the gain height, the higher the height of the transceiver device, the narrower the peak of the gain interference effect, and the more the number within the same height range. Measuring at different heights multiple times, the height range of the gain interference can cover a larger pitch angle of the aircraft. The weights of the measurement data obtained each time are different. Therefore, in order to make the measurement data more accurate, it is necessary to calculate the complex weighting coefficient for each measurement, and calculate a more accurate measurement result through the complex weighting coefficient and the measurement data for each time. Description of the Drawings

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0050] Figure 1It is a schematic structural diagram of an RCS test system for testing an aircraft provided by an embodiment of the present invention;

[0051] Figure 2 It is an interference gain curve graph of a single RCS measurement provided by an embodiment of the present invention;

[0052] Figure 3 It is an interference gain curve graph of multiple RCS measurements provided by an embodiment of the present invention;

[0053] Figure 4 It is a comparison graph of the target echo gain at different heights and the synthesized target echo gain when testing twice provided by an embodiment of the present invention;

[0054] Figure 5 It is a comparison graph of the target echo gain at different heights and the synthesized target echo gain when testing three times provided by an embodiment of the present invention;

[0055] Figure 6 It is a comparison graph of the target echo gain at different heights and the synthesized target echo gain when testing five times provided by an embodiment of the present invention.

[0056] In the figure:

[0057] 1 - Transceiver device;

[0058] 2 - Measurement system;

[0059] 3 - Aircraft;

[0060] 4 - Support device;

[0061] R0 - Test distance;

[0062] H t - Target height. Specific embodiments

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0064] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; unless otherwise specified or stated, the term "plurality" means two or more; the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] In the description of this specification, it should be understood that the orientation terms such as "upper" and "lower" described in the embodiments of the present invention are described from the angles shown in the drawings and should not be construed as limiting the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that an element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element.

[0066] As Figures 1 to 6 shown, the embodiments of the present invention provide a method for testing the RCS of an aircraft, including:

[0067] Determine the gain height according to the test distance, the target height, and the test wavelength; wherein, the test distance is the horizontal distance between the transceiver device and the aircraft, the target height is the height of the aircraft, the gain height is the height at which the direct wave and the ground-reflected wave generate gain interference, the direct wave is the radar wave directly emitted by the transceiver device to the aircraft, and the ground-reflected wave is the radar wave emitted by the transceiver device and reflected by the ground to the aircraft;

[0068] Control the transceiver device to perform RCS tests at different test heights to obtain a plurality of test data; wherein, the transceiver device is used to transmit and receive radar waves, and the test height is a positive integer multiple of the gain height;

[0069] Determine the complex weighting coefficient according to the test distance, the gain height, and multiple different height values of the aircraft; wherein, the height value is the height of any point on the surface and inside of the aircraft from the ground;

[0070] Process the test data according to the complex weighting coefficient to improve the RCS test accuracy.

[0071] In this embodiment, first determine the gain height at which the direct wave and the ground reflected wave can interfere according to the test distance, target height, and test wavelength. Fix the transceiver device at the gain height, and the direct wave and the transmitted wave can interfere, improving the accuracy of the test data. However, the method of measuring once can only produce obvious effects within a relatively narrow range above and below the target height. When the pitch angle of the aircraft is large, the effect of gain interference on the part where the aircraft deviates significantly upward or downward from the target height is not obvious. Measure the transceiver device multiple times at positions that are multiples of the gain height. The higher the height of the transceiver device, the narrower the peak of the gain interference effect, and the more numerous within the same height range. Measuring multiple times at different heights can cover a larger pitch angle of the aircraft. The weights of the measurement data obtained each time are different. Therefore, in order to make the measurement data more accurate, it is necessary to calculate the complex weighting coefficient for each measurement, and calculate a more accurate measurement result through the complex weighting coefficient and the measurement data for each time.

[0072] It should be noted that multiple transceiver devices can be set at multiple measurement heights to achieve multiple tests, or a single transceiver device that can move up and down can be set for multiple tests. When the test height is n times the gain height, the width of the gain peak generated is 1 / n of the width of the gain peak at 1 time the gain height.

[0073] In some embodiments of the present invention, determining the gain height according to the test distance, target height, and test wavelength includes:

[0074] Determine the gain height according to the test distance, target height, and test wavelength through the antenna height formula;

[0075] The antenna height formula is:

[0076]

[0077] where H1 is the gain height, λ is the test wavelength, R0 is the test distance, and H t is the target height.

[0078] In this embodiment, first determine the appropriate test distance, test wavelength, and target height according to the test purpose, and then calculate the gain height at which the direct wave and the ground reflected wave can produce gain interference according to the determined test distance, test wavelength, and target height. It is necessary to reasonably install the transceiver device according to the antenna height formula, so that the propagation path lengths of the direct wave and the reflected wave differ by λ / 2, so that the multipath wave after being reflected by the ground (the ground reflectivity is -1, and the phase will change by λ / 2 after reflection) and the direct wave have the same phase when reaching the target area, so as to achieve the goal of enhancing the echo signal and improving the signal-to-noise ratio.

[0079] In some embodiments of the present invention, determining the complex weighting coefficient according to the test distance, gain height, and multiple different height values of the aircraft includes:

[0080] Determining the amplitude of the complex weighting coefficient according to the test distance, gain height, and multiple different height values;

[0081] Determining the phase of the complex weighting coefficient according to the test distance and gain height;

[0082] Determining the complex weighting coefficient according to the amplitude and phase.

[0083] In this embodiment, the complex weighting coefficient includes an amplitude and a phase. After calculating the amplitude and phase respectively, more accurate RCS test data can be obtained according to the amplitude and phase.

[0084] In some embodiments of the present invention, determining the amplitude of the complex weighting coefficient according to the test distance, gain height, and height value includes:

[0085] Determining the amplitude of the complex weighting coefficient according to the test distance, gain height, and height value through the amplitude formula;

[0086] The amplitude formula is:

[0087] AM = I

[0088] A = [A1, A2,..., A N 1×N ,

[0089]

[0090] A is the echo level amplitude, M is the amplitude, I is the constant value of the interference gain in the height direction, N is the total number of RCS tests, n is the nth RCS test, at the nth RCS test, the test height is n * H1, H1 is the gain height, h is the height value, k is the number of height values, and R0 is the test distance.

[0091] In this embodiment, N is preferably 2 - 5. I is the intensity constant value of the interference gain along the height direction, which can be 1 or other values, and 1 is preferably used for easier calculation. The height value is any value between the maximum height and the minimum height of the aircraft. AM = I can also be written as According to the least squares method, the least squares solution of AM = I is where A+ is the plus inverse of A, and thus the amplitude M of the weighting coefficient is obtained.

[0092] In some embodiments of the present invention, determining the complex weighting coefficient according to the amplitude and phase includes:

[0093] Determining the complex weighting coefficient according to the amplitude and phase through the phase formula;​

[0094] The phase formula is:

[0095]

[0096]

[0097] Wherein, is the phase, H1 is the gain height, n is the nth RCS test, at the nth RCS test, the test height is n * H1, λ is the test wavelength, R0 is the test distance, H t is the target height, and h is the height value.

[0098] In this embodiment, when R0 >> h, there is:

[0099]

[0100] In some embodiments of the present invention, determining the complex weighting coefficient according to the amplitude and phase includes:

[0101] Determining the complex weighting coefficient according to the amplitude and phase through the following formula:

[0102]

[0103] Wherein, C n is the complex weighting coefficient, n is the nth RCS test, M is the amplitude, is the phase, and j is the imaginary unit.

[0104] In this embodiment, e is common knowledge in nature.

[0105] In some embodiments of the present invention, processing the test data according to the complex weighting coefficient to improve the RCS test accuracy includes:

[0106] Processing the test data according to the complex weighting coefficient through the following formula to improve the RCS test accuracy:

[0107]

[0108] Wherein, E is the test data, E' is the processed test data, C n is the complex weighting coefficient, and N is the total number of RCS tests.

[0109] In some embodiments of the present invention, the test data is the data of the aircraft echo after I / Q adjustment.

[0110] The embodiment of the present invention provides a system for testing the RCS of an aircraft, which is used to implement the method of any one of the above, including:

[0111] A transceiver device for transmitting and receiving electromagnetic waves;

[0112] A measurement system electrically connected to the transceiver device for processing the echo data received by the transceiver device;

[0113] An aircraft for receiving reflected electromagnetic waves;

[0114] A support device for supporting the aircraft and adjusting the pitch angle of the aircraft.

[0115] The system provided in this embodiment and the above method are based on the same inventive concept, so they have the same beneficial effects. For specific effects, please refer to the above text and will not be elaborated here.

[0116] In some embodiments of the present invention, the support device is a turntable or a metal bracket with a rotating top.

[0117] In this embodiment, the turntable is a high-precision turntable, the metal bracket is a low-scattering bracket, and the rotating top of the metal bracket is a high-precision rotating top.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for testing the RCS of an aircraft, characterized in that, Including: Determine the gain height according to the test distance, target height, and test wavelength; wherein, the test distance is the horizontal distance between the transceiver device and the aircraft, the target height is the height of the aircraft, the gain height is the height at which direct wave and ground reflected wave undergo gain interference, the direct wave is the radar wave directly emitted by the transceiver device to the aircraft, and the ground reflected wave is the radar wave emitted by the transceiver device and reflected by the ground to the aircraft; Control the transceiver device to perform RCS tests at different test heights to obtain multiple test data; wherein, the transceiver device is used to transmit and receive radar waves, and the test height is a positive integer multiple of the gain height; Determine the complex weighting coefficient according to the test distance, the gain height, and multiple different height values of the aircraft; wherein, the height value is the height of any point on the surface and inside of the aircraft from the ground; Process the test data according to the complex weighting coefficient to improve the RCS test accuracy; The determining the complex weighting coefficient according to the test distance, the gain height, and multiple different height values of the aircraft includes: Determine the amplitude of the complex weighting coefficient according to the test distance, the gain height, and multiple different height values; Determine the phase of the complex weighting coefficient according to the test distance and the gain height; Determine the complex weighting coefficient according to the amplitude and the phase; The determining the amplitude of the complex weighting coefficient according to the test distance, the gain height, and the height value includes: Determine the amplitude of the complex weighting coefficient according to the test distance, the gain height, and the height value through the amplitude formula; The amplitude formula is: A is the echo level amplitude, M is the amplitude, I is the constant value of the interference gain in the height direction, N is the total number of RCS tests, n is the nth RCS test, at the nth RCS test, the test height is n*H1, H1 is the gain height, h is the height value, k is the number of height values, and R0 is the test distance.

2. The method according to claim 1, characterized in that, The determining the gain height according to the test distance, target height, and test wavelength includes: Determine the gain height according to the test distance, target height, and test wavelength through the antenna height formula; The antenna height formula is: Wherein, H1 is the gain height, λ is the test wavelength, R0 is the test distance, and H t is the target height.

3. The method according to claim 1, characterized in that, The determining the complex weighting coefficient according to the amplitude and the phase includes: Determine the complex weighting coefficient according to the amplitude and the phase through the phase formula; The phase formula is: Wherein, is the phase, H1 is the gain height, n is the nth RCS test. At the nth RCS test, the test height is n*H1, λ is the test wavelength, R0 is the test distance, and H t is the target height, and h is the height value.

4. The method according to claim 3, characterized in that, The determining the complex weighting coefficient according to the amplitude and the phase includes: Determine the complex weighting coefficient according to the amplitude and the phase through the following formula: Among them, C n is the complex weighting coefficient, n is the nth RCS test, M is the amplitude, is the phase, and j is the imaginary unit.

5. The method according to claim 4, characterized in that, The processing the test data according to the complex weighting coefficient to improve the RCS test accuracy includes: Process the test data according to the complex weighting coefficient through the following formula to improve the RCS test accuracy: Wherein, E is the test data, E' is the processed test data, and C n is the complex weighting coefficient, and N is the total number of RCS tests.

6. The method according to claim 5, characterized in that, The test data is the data after I / Q adjustment of the aircraft echo.

7. A system for testing the RCS of an aircraft, characterized in that, For implementing the method according to any one of claims 1-6, including: The transceiver device, for transmitting and receiving electromagnetic waves; A measurement system, electrically connected to the transceiver device, for processing the echo data received by the transceiver device; An aircraft, for receiving reflected electromagnetic waves; A support device, for supporting the aircraft and adjusting the pitch angle of the aircraft.

8. The system according to claim 7, characterized in that, The support device is a turntable or a metal bracket with a rotating top.

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