Low-scattering carrier for RCS (radar cross section) test of leading edge of wing

Abstract

The invention provides a low-scattering carrier for an airfoil front edge RCS test, the low-scattering carrier comprises a front edge cover plate and a carrier main body which are detachably connected, the carrier main body and a carrier end face are of an integrally formed metal hollow structure, the front edge of the carrier main body is of a linear structure attached to an airfoil front edge wave-absorbing structure, and the front edge of the carrier main body is of a rectangular structure attached to the airfoil front edge wave-absorbing structure. The rear edge of the carrier body is of a linear structure parallel to the front edge. According to the low-scattering carrier, the drop-shaped design is adopted, the carrier end face and the carrier body are integrally formed, and the airfoil front edge and rear edge parallel structure is used, so that the influence of the edge on angular domain scattering assessment is reduced, and the vertical polarization and horizontal polarization electromagnetic scattering characteristics of the carrier are greatly reduced; and the stealth performance of the carrier in various radar environments is further improved. The low-scattering carrier provided by the invention has a good traveling wave suppression effect, and in an X wave band 0-50 degrees range, the RCS mean value of polarization in the horizontal direction can reach-45dBsm, and the RCS mean value of polarization in the vertical direction can reach-40dBsm.

Description

Technical Field

[0001] The invention relates to the field of electromagnetic scattering measurement, and in particular to a low-scattering carrier for wing leading edge RCS testing. Background Art

[0002] With the continuous development of radar detection technology, the stealth performance of aircraft is required to be improved simultaneously. The mirror scattering of the leading and trailing edges of the wing is one of the important scattering sources of aircraft. In order to improve the survivability of aircraft, it is necessary to optimize the radar stealth design. The main processing method of the existing technology is to use the absorbing structure design at the scattering source to transmit-absorb-reflect-absorb-transmit the radar incident wave, reduce the intensity of its reflected echo, and reduce scattering.

[0003] During the design and development of the absorbing structure, a large number of data tests and simulation calculation results need to be continuously iterated and verified. Since the full-scale model of the aircraft or the wing components are larger than the size of the general darkroom quiet area, RCS testing cannot be performed. Therefore, a low-scattering carrier of the absorbing structure is designed for RCS testing, so that it can enter the darkroom for testing while also avoiding testing the leading edge alone, exposing the internal structure to the outside to form a new scattering source that affects the test results.

[0004] Patent CN114104331A discloses an absorber for reducing low-frequency scattering, wherein the carrier for reducing low-frequency scattering is approximately rhombus-shaped, and the advantage of the carrier is that it can reduce the low-frequency scattering of the bottom edge of the component to be tested during RCS testing, wrap the bottom edge of the component to be tested and shield the inner cavity structure of the component. However, due to shape limitations, it is difficult to use the low-scattering carrier for RCS testing of slender dihedral-like wing leading edge absorber structures.

[0005] Patent CN115856774A discloses a low-scattering carrier for RCS testing, which is a double-teardrop-shaped spliced ​​structure. The carrier has a good surface current guiding effect, can reduce strong scattering sources such as specular scattering and multiple scattering, and can effectively avoid the fluctuation of the carrier body in the low-scattering angle region. Also due to its shape limitation, it is difficult to use it as a low-scattering carrier for RCS testing of slender dihedral-like wing leading edge absorbing structures.

[0006] Patent CN114355311A discloses a low-scattering carrier and test method for RCS test of wing leading edge wave absorbing structure. The low-scattering carrier itself is at a lower scattering level due to the adoption of stealth design measures. Due to the special structure of the carrier, it can be used for RCS test of wing leading edge wave absorbing structure, and the test method proposed based on the low-scattering carrier can be directly applied to the low-scattering carrier. The inventor has carefully studied the structure of the low-scattering carrier and provided a low-scattering carrier for RCS test of wing leading edge wave absorbing structure with a lower scattering level. Summary of the invention

[0007] The main purpose of the present invention is to provide a low-scattering carrier for RCS testing of the leading edge of a wing. The low-scattering carrier of the present invention adopts a teardrop-shaped design, the carrier end face and the carrier body are integrally formed, and the leading edge and the trailing edge of the wing are parallel. The influence of the edge on the scattering in the test angle domain is reduced, and the vertical polarization and horizontal polarization electromagnetic scattering characteristics of the carrier are greatly reduced. In the X-band range of 0-degree-50 degrees, the RCS average of horizontal polarization can reach -45dBsm, and the RCS average of vertical polarization can reach -40dBsm.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: A low-scattering carrier for RCS test of a wing leading edge, used for RCS test of a wave-absorbing structure at the leading edge of a wing, the low-scattering carrier comprising a leading edge cover plate, a carrier body and a carrier end face, the leading edge cover plate and the carrier body being detachably connected, the carrier body being a flat long strip structure that is thick in the middle and gradually flattened at the front and rear sides, and the front and rear ends of the carrier body being in a water drop shape with one thick and one thin; The carrier end faces are arranged in two, one thick and one thin, which correspond to the two ends of the flat long strip structure, one thick and one thin, arranged on the carrier body respectively; the side lines of the carrier end faces are parallel.

[0009] The leading edge of the carrier body is a linear structure that fits the wing leading edge absorbing structure, and the curved surface at the connection between the leading edge cover plate and the carrier body is tangent and continuous without surface step difference; the trailing edge of the carrier body is a linear structure parallel to the leading edge.

[0010] Optionally, the front edge cover plate is a cover plate structure that fits with one side of the front edge of the carrier body and is detachably disposed on one side of the front edge of the carrier body.

[0011] Optionally, the carrier end face is a flat cover structure in which the upper and lower curved surfaces are contracted into a curve, and the edge diffraction of the curve is used to replace the mirror scattering caused by the plane of the carrier end face, thereby reducing the lateral RCS.

[0012] Optionally, the carrier end face and the carrier body are an integrally formed metal hollow structure. The integrated structure of the carrier end face and the carrier body reduces the interference of the connection gap on the scattering of electromagnetic waves, and the metal material ensures that the carrier has good conductivity and stability.

[0013] Optionally, the angle between the carrier body and the carrier end face is greater than or equal to 65°, and a larger angle helps to reduce scattering and improve stealth performance.

[0014] Optionally, the width of the carrier body is greater than or equal to 3.2 times the wavelength of a signal corresponding to the lowest frequency tested during an RCS test.

[0015] Optionally, the carrier has no surface step difference and a surface roughness of no more than 1.6, so as to reduce scattering of electromagnetic waves when propagating on the carrier.

[0016] Optionally, the length of the low-scattering carrier is 4300 mm, the width of the low-scattering carrier is 800 mm, and the height of the low-scattering carrier is 200 mm.

[0017] Optionally, when testing the wing surface absorbing structure, the leading edge cover is removed and the wing surface leading edge absorbing structure is installed; when verifying the RCS of the low-scattering carrier, the leading edge cover is used to shield the cavity of the low-scattering carrier.

[0018] The present invention adopts the design measures of stealth shape to design the carrier structure. The curved surface is tangent and continuous without surface step difference, which has a good current guiding effect. When performing RCS test on the dihedral reflector absorbing structure such as the leading edge of the wing, the edge scattering of the existing absorbing structure and the disorderly scattering caused by the internal structure are eliminated, so that the scattering is at a lower level. The described test method is used to perform RCS test on the carrier equipped with the wing leading edge absorbing structure, and the reduction effect of the leading edge absorbing structure on the peak of the specular scattering is obtained.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The low-scattering carrier of the present invention has a good traveling wave suppression effect. In the X-band range of 0-degree-50 degrees, the average RCS of horizontal polarization can reach -45dBsm, and the average RCS of vertical polarization can reach -40dBsm. It has relatively low low-scattering performance. When the carrier is used in combination with a wing surface absorbing structure, the precise polarization RCS of the wing surface absorbing structure can be obtained.

[0020] 2. The low-scattering carrier of the present invention adopts a teardrop-shaped design and a parallel structure of the leading edge and the trailing edge of the wing, which reduces the influence of the edge on the scattering in the test angle domain, greatly reduces the vertical polarization and horizontal polarization electromagnetic scattering characteristics of the carrier, and further improves the stealth performance of the carrier in a variety of radar environments; and the teardrop-shaped design and the parallel structure of the leading edge and the trailing edge of the wing are relatively simple and easy to manufacture and maintain.

[0021] 3. The integrated design and detachable connection mode of the low-scattering carrier of the present invention improve the accuracy and efficiency of RCS measurement of the wing leading edge absorbing structure, reduce radar interference, and improve the stealth of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1 is an isometric view of the leading edge cover plate of the present invention not mounted on the carrier body; Figure 2 is a top view of the leading edge cover plate of the present invention when it is not installed on the carrier body; Figure 3 is an isometric view of the leading edge cover plate of the present invention mounted on a carrier body; Figure 4 is a cross-sectional view in the thickness direction when the leading edge cover plate of the present invention is installed on the carrier body; Figure 5 It is a simulation test curve diagram of the low scattering carrier of the present invention in the X-band; In the figure: 1 front edge cover plate, 2 carrier body, 3 carrier end surface, 4 front edge, 5 rear edge, 6 seam. DETAILED DESCRIPTION

[0023] like Figures 1 to 4 As shown, a low-scattering carrier for RCS test of wing leading edge absorbing structure is used for RCS test of wing leading edge absorbing structure, the low-scattering carrier comprises a leading edge cover plate 1, a carrier body 2 and a carrier end face 3, the leading edge cover plate 1 and the carrier body 2 are detachably connected; the outer shape of the carrier body 2 is a long strip structure which is thick at one end and thin at the other end and gradually flattened, and the cross-section of the carrier body 2 in the thickness direction is a water drop shape which is blunt at the front and pointed at the back; the carrier end face 3 is provided with two, one thick and one thin, which respectively correspond to the two ends of the flat long strip structure, one thick and one thin, provided on the carrier body 2, the side lines of the carrier end face 3 are parallel, and the parallel side lines help to reduce scattering; the leading edge 4 of the carrier body 2 is a linear structure fitted with the wing leading edge absorbing structure, and the curved surface at the connection between the leading edge cover plate 1 and the carrier body 2 is tangent and continuous without surface step difference, and the trailing edge 5 of the carrier body 2 is a linear structure parallel to the leading edge 4.

[0024] In a preferred embodiment, the leading edge cover plate 1 is a cover plate structure that is bonded to one side of the leading edge 4 of the carrier body 2. Its appearance is the same as that of the wing leading edge absorbing structure. It is installed on the carrier body to test the RCS of an all-metal carrier. It can be removed and the wing leading edge absorbing structure can be installed in situ to test the RCS of the carrier after the wing leading edge absorbing structure is installed.

[0025] In a preferred embodiment, the carrier end face 3 is a flattened upper and lower curved surface that is contracted into a curve, and the edge diffraction of the curve is used to replace the mirror scattering caused by the plane of the carrier end face, thereby reducing the lateral RCS.

[0026] In a preferred embodiment, the carrier end face 3 and the carrier body 2 are an integrally formed metal hollow structure. The integral forming ensures the continuity and smoothness of the carrier surface and reduces the scattering caused by discontinuity at the connection. The use of metal material can effectively guide the current and reduce the scattering of electromagnetic waves.

[0027] In a preferred embodiment, the angle between the carrier end face 3 and the carrier body 2 is greater than or equal to 65°. A larger angle helps to smooth the transition, reduce edge effects, further reduce scattering, and improve stealth performance.

[0028] In a preferred embodiment, the width of the carrier body 2 is greater than or equal to 3.2 times the wavelength of the signal corresponding to the lowest frequency tested during the RCS test, so that the carrier body meets the RCS test requirements of different frequencies.

[0029] In a preferred embodiment, the carrier has no surface step difference and the surface roughness is not greater than 1.6, thereby reducing the scattering of electromagnetic waves when propagating on the carrier; the curved surface between the carrier body 2 and the leading edge cover plate 1 is tangent and continuous, which has a good current guiding effect and avoids the problem of introducing new weak scattering sources due to discontinuous changes in the shape.

[0030] In a preferred embodiment, the length of the low-scattering carrier is 4300 mm, the width of the low-scattering carrier is 800 mm, and the height of the low-scattering carrier is 200 mm.

[0031] In a preferred embodiment, when performing an RCS test on the wing leading edge absorbing structure, the leading edge cover plate 1 is removed and the wing leading edge absorbing structure is installed; when verifying the RCS of the low-scattering carrier, the leading edge cover plate 1 is used to shield the cavity of the low-scattering carrier.

[0032] When testing the RCS of the wing leading edge absorbing structure, the present invention removes the leading edge cover plate 1, installs the wing leading edge absorbing structure at the position of the leading edge cover plate 1, and the edge of the low-scattering carrier is closely connected to the wing leading edge absorbing structure without a step difference, and aluminum foil is pasted at the seam between the two, ensuring that no surface discontinuous echo reflection and strong specular reflection source will appear at the connection; when verifying the RCS of the low-scattering carrier, the leading edge cover plate 1 and the carrier body are connected to block the cavity of the low-scattering carrier, so as to verify the low scattering property of the low-scattering carrier.

[0033] In a preferred embodiment, the low-scattering carrier has an average vertical polarization scattering RCS of -40 dBsm and an average horizontal polarization scattering RCS of -45 dBsm in the X-band azimuth of 0 to 50 degrees, thereby providing the aircraft with stronger stealth performance.

[0034] Combination Figure 2-4The length of the absorbing carrier of the leading edge of the wing to be tested is 3500mm, and the total length of the carrier must be smaller than the quiet zone size of the darkroom to ensure the stability and accuracy of the test environment; the wavelength corresponding to the center frequency is 32mm, and the width of the carrier body must be greater than or equal to 3.2 times the wavelength corresponding to the lowest test frequency, so that the size of the carrier in the width direction is in the optical zone of electromagnetic scattering, avoiding the problem that the RCS fluctuates violently with frequency changes due to the small size of the carrier being in the resonance zone, and the shape stealth measures have no obvious effect on RCS reduction; the angle between the carrier body 2 and the carrier end face 3 is greater than or equal to 65°, which reduces scattering and improves stealth performance.

[0035] In order to verify the accuracy of RCS scattering of the carrier test wing leading edge absorbing structure after being separated from the aircraft structure, a carrier with L of 4300mm, W1 of 800mm, and H of 200mm was selected for testing. The carrier is a metal hollow structure, the leading edge 4 and the trailing edge 5 of the carrier body are parallel, the angle between the carrier body 2 and the carrier end face 3 is equal to 65°, and the seam 6 of the carrier is covered with aluminum foil, and the following test is performed. The specific test method is as follows: Step 1: Conduct a darkroom background test; Step 2: Select the horn antenna according to the signal band of the RCS test and install the horn antenna; Step 3: Set the polarization mode; Step 4: Install the front edge cover plate on the carrier body, and cover the seam between the front edge cover plate and the carrier body with aluminum foil; Step 5: placing the low-scattering carrier on a turntable for RCS testing, with the length direction of the low-scattering carrier parallel to the 0° direction of the incident electromagnetic wave; Step 6: Perform RCS test on a low-scattering carrier made of all-metal material and record the test data value; Step 7: Remove the leading edge cover plate of the low-scattering carrier, install the wing leading edge absorbing structure on the carrier body, and cover the seam between the wing leading edge absorbing structure and the carrier body with aluminum foil; Step 8: Place the low-scattering carrier with the wing leading edge absorbing structure installed on the turntable, with the length direction parallel to the 0° direction of the incident electromagnetic wave; Step 9: Perform an RCS test on the low-scattering carrier after installing the wing leading edge absorbing structure, and record the test data value; Step 10: Compare the test data value results of step 6 and step 9 to obtain the reduction amount of the leading edge peak value of the metal of the low scattering carrier caused by the wing leading edge absorbing structure; Step 11: Repeat steps 3 to 10 to complete the RCS test of all polarization modes at one frequency; Step 12: Repeat Step 2 to Step 11 to complete the RCS test at all frequencies.

[0036] Figure 5 The RCS simulation curve of the carrier within the above value range is calculated by multi-layer fast multipole algorithm simulation, where VV represents the simulation test curve of the vertical polarization of the carrier, and HH represents the simulation test curve of the horizontal polarization of the carrier. It can be seen from the figure that, except for the 26° peak close to -20dBsm, the RCS of the horizontal polarization HH is lower than -30dBsm in most azimuths, and the average value can reach -40dBsm; the RCS of the vertical polarization VV is lower than -40dBsm in most azimuths, and the average value can reach -45dBsm. The carrier is at a lower scattering level through the stealth design.

[0037] The low-scattering carrier of the present invention adopts a teardrop-shaped design and a structure in which the leading edge and trailing edge of the wing are parallel, which greatly reduces the vertical polarization and horizontal polarization electromagnetic scattering characteristics of the carrier. Compared with the teardrop-shaped low-scattering carrier in 202210230306.0, it has great optimization and modification, and the reduction in the X-band can reach 15dBsm, providing the aircraft with stronger stealth performance.

[0038] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A low-scattering carrier for RCS testing of a wing leading edge absorbing structure, characterized by: The low-scattering carrier comprises a front edge cover plate (1), a carrier body (2) and a carrier end surface (3); the front edge cover plate (1) and the carrier body (2) are detachably connected; the carrier body (2) is a flat long strip structure that is thick in the middle and gradually flattens at the front and rear sides; the front and rear ends of the carrier body (2) are in the shape of a water droplet, one thick and one thin; The carrier end surface (3) is provided with two, one thick and one thin, which respectively correspond to the two ends of the flat long strip structure (one thick and one thin) provided on the carrier body (2); the side lines of the carrier end surface (3) on both sides are parallel. The leading edge (4) of the carrier body (2) is a linear structure that fits the wing leading edge wave absorbing structure, and the curved surface at the connection between the leading edge cover plate (1) and the carrier body (2) is tangent, continuous and has no surface step difference; the trailing edge (5) of the carrier body (2) is a linear structure that is parallel to the leading edge (4).

2. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: The front edge cover plate (1) is a cover plate structure that fits on one side of the front edge (4) of the carrier body (2), and is detachably arranged on one side of the front edge of the carrier body.

3. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: The carrier end surface (3) is a flat cover structure in which the upper and lower curved surfaces are contracted into a curve.

4. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: The carrier end surface (3) and the carrier body (2) are an integrally formed metal hollow structure.

5. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: The included angle between the carrier end surface (3) and the carrier body (2) is greater than or equal to 65°.

6. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: The width of the carrier body (2) is greater than or equal to 3.2 times the wavelength of the signal corresponding to the lowest frequency tested during the RCS test.

7. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: The carrier has no surface step difference and a surface roughness of no more than 1.

6.

8. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: The length of the low scattering carrier is 4300 mm. The width of the low scattering carrier is 800 mm. The height of the low scattering carrier is 200 mm.

9. According to claim 1, a low-scattering carrier for RCS testing of a wing leading edge absorbing structure is characterized by: When testing the wing surface wave absorbing structure, the leading edge cover plate (1) is removed and the wing surface wave absorbing structure is installed; when verifying the RCS of the low scattering carrier, the leading edge cover plate (1) is used to shield the cavity of the low scattering carrier.

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