Method for rapidly calculating RCS of coating unmanned aerial vehicle under complex background

Abstract

The invention relates to a method for rapidly calculating the RCS of a coated unmanned aerial vehicle under a complex background, and belongs to the field of stealth target electromagnetic scattering calculation. Comprising the following steps: determining reflection coefficients of a single-layer wave-absorbing material with a PEC substrate at different incident angles according to an equivalent transmission line theory; calculating induced current generated by incident electromagnetic waves on the surface of the target coated with the single-layer wave-absorbing material according to the reflection coefficient; based on the induced current, utilizing physical optics and physical diffraction theories to calculate scattered fields of all the illuminated surface elements, and superposing all the calculated scattered fields; the scattering field of each surface element on the sea surface model at a fixed angle is obtained through vector superposition of the scattering fields obtained through an EPO'field and a TSM; and finally, superposing all the scattered fields, and calculating the total field RCS of the complex sea background and unmanned aerial vehicle composite model based on the superposed total scattered field. According to the method, the RCS of the coating unmanned aerial vehicle under the complex background can be quickly calculated.

Description

Technical Field

[0001] The present invention relates to the field of stealth target electromagnetic scattering calculation, and more specifically, to a method for quickly calculating the RCS of a coated unmanned aerial vehicle under a complex background. Background Art

[0002] Stealth technology is a comprehensive technology that controls and reduces the various signal characteristics of weapon systems that are detected, tracked, identified and attacked by the enemy, reduces the probability of weapon systems being discovered and attacked, and thus improves their combat capability and survivability. Among them, Radar Cross Section (RCS) is the most critical concept in radar stealth technology. Therefore, an efficient RCS calculation method is crucial for evaluating the stealth performance of drones.

[0003] When electromagnetic waves hit the surface of the drone, they will produce various scattering mechanisms such as specular reflection, coupled scattering between the drone's structural components, cavity scattering of the air inlet, and edge diffraction generated by the edges of the drone's wings and tail (such as Figure 1 When calculating the composite scattering field of large-area sea surface and UAV, it is necessary to consider not only the scattering mechanism of the sea surface, but also the sea surface-target (such as Figure 2 Path ① in the middle), target-sea surface (as shown in Figure 2 The calculation diagram of the scattering path is shown in the figure below. Figure 2 As shown in the figure, only some scattering path diagrams are listed. Based on the above scattering mechanism analysis, the combination of shooting and bouncing ray (SBR) method, physical theory of diffraction (PTD) and two-scale model (TSM) can effectively solve the calculation of the above various scattering fields.

[0004] Currently, there is no related method for fast calculation of RCS of coated UAVs under complex backgrounds. Summary of the invention

[0005] The technical problems to be solved by the present invention are:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a method for quickly calculating the RCS of a coating drone under a complex background, which is used to calculate the RCS of a coating drone under a complex background.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A method for quickly calculating the RCS of a coating drone under complex background, characterized by comprising:

[0009] Step 1: Determine the reflection coefficient of the single-layer absorber with PEC substrate at different incident angles according to the equivalent transmission line theory;

[0010] Step 2: Calculate the induced current generated by the incident electromagnetic wave on the target surface coated with a single layer of absorbing material according to the reflection coefficient; use the geometric optics method to track the triangular surface elements illuminated by the incident wave and the triangular surface elements illuminated by each order of reflected waves, calculate the scattering field of each illuminated surface element based on the induced current using physical optics and physical diffraction theory, and superimpose the calculated scattering fields;

[0011] Step 3: For the scattered field of each surface element on the sea surface model at a fixed angle, use E PO' The field and the scattered field obtained by TSM are obtained by vector superposition;

[0012] Step 4: For the composite scene of sea surface and UAV, for each triangular facet of the UAV, the far-field scattering is composed of the PO field E from the triangular facet surface PO and the PTD field E from the three edges of the triangle element PTD The direct scattering of the sea surface can be obtained by TSM. The coupled scattering field between the sea surface and the UAV comes from the PO field of the triangular surface element of the aircraft surface or the PO' field of the triangular surface element of the sea surface. PO' ,Right now:

[0013]

[0014] Among them, the first Σ represents the superposition of different orders of bouncing rays, and the second Σ represents the superposition of the far-zone scattered fields of each order of illuminated triangles; They are the PTD fields of the three edges of the triangle surface element;

[0015] Step 5: Based on E total Get the total field RCS of the complex sea background and UAV composite model:

[0016]

[0017] Where R is the reflection coefficient.

[0018] A further technical solution of the present invention: the reflection coefficient described in step 1 is:

[0019]

[0020] In the formula,

[0021]

[0022] Wherein, the subscript v represents vertical polarization, h represents horizontal polarization, and the same below; j represents an imaginary unit; d is the coating thickness; θ i represents the incident angle, the subscript i represents the incident field; ε is the relative dielectric constant of the coating, μ is the relative magnetic permeability of the coating; k 0 =2π / λ is the free space wave number;

[0023] When θ i = 0, at this time R v =R h ,Right now:

[0024]

[0025] A further technical solution of the present invention is to calculate the scattered field of each facet using physical optics based on the induced current, using the formula:

[0026]

[0027] in, is the scattered wave unit vector, Δs is the illuminated target surface area, r is the distance from the upward radar to the target center, k = 2π / λ is the electromagnetic wave number, η is the input impedance of the upper boundary surface of the absorbing coating, E h and E v are the horizontal polarization electric field component and the vertical polarization electric field component, and are the unit horizontal polarization wave and vertical polarization wave vector respectively, J is the induced current, and M is the induced magnetic current.

[0028] A further technical solution of the present invention is to calculate the scattered field of each illuminated facet using the physical diffraction theory based on the induced current, and the formula used is:

[0029]

[0030]

[0031] in, is the tangent unit vector of the edge structure of the UAV wing, tail wing, etc., r' is the position coordinate of the midpoint of a certain edge of the triangular surface element, β i and β s The angle between the incident direction and the scattering direction and the edge, D e , D m and D em is the diffraction coefficient, E i is the incident electric field of the electromagnetic wave incident on the surface of the absorbing coating, H i is the incident magnetic field when the electromagnetic wave is incident on the surface of the absorbing coating.

[0032] A further technical solution of the present invention: Step 3 is specifically:

[0033]

[0034] R v '=R v ·ρ s

[0035] R' h =R h ·ρ s

[0036] in,

[0037]

[0038] Among them, ρ s is the rough surface reflection factor, τ=σ h cosθ / λ, λ is the wavelength of the incident wave, σ h is the height standard deviation, which is related to the sea surface wind speed U:

[0039] σ h =0.0051U 2

[0040] The scattering coefficient of an arbitrarily inclined micro-rough surface element can be calculated by the following formula:

[0041]

[0042] Among them, S ζ (q l ) represents the power spectrum function of the micro-rough surface element; represents the polarization factor in the global coordinate system, that is:

[0043]

[0044] in, is the polarization unit vector corresponding to the incident and scattered unit vectors in the local coordinate system. Its relationship with the global polarization unit vector can be expressed as:

[0045]

[0046] in,

[0047]

[0048] Therefore, the total field of the two-scale sea surface scattering model can be expressed as:

[0049]

[0050] Where r is the distance from the upward radar to the center of the sea surface, and the phase term It can be expressed as:

[0051]

[0052] Among them, ξ∈[-1 / 2,1 / 2], Represents the maximum phase difference within the bin, r mn is the position vector of each face element relative to the origin of the coordinate system, Δρ mn =q·r mn is the phase delay caused by the relative position of each element.

[0053] A further technical solution of the present invention is as follows: the above method is accelerated by using MPI parallel computing, and the parallel computing environment is MSMPI under the Windows system.

[0054] A computer system, characterized in that it comprises: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned method.

[0055] A computer-readable storage medium, characterized in that it stores computer-executable instructions, which are used to implement the above method when executed.

[0056] A computer program product, characterized by comprising computer executable instructions, wherein the instructions are used to implement the above method when executed.

[0057] The beneficial effects of the present invention are:

[0058] The present invention provides a method for quickly calculating the RCS of a coating UAV under complex background. According to the multi-scale structural characteristics of the sea surface and the structural characteristics of the UAV itself, the SBR-PTD-TSM hybrid method is adopted, and the CPU+GPU parallel acceleration technology is combined to quickly and accurately establish an electromagnetic scattering model of a low-altitude sea-skimming unmanned composite scene, thereby quickly calculating the RCS of the coating UAV under complex background.

[0059] 1. The RCS of the composite scene of the sea surface and the stealth UAV can be calculated under different sea environment parameters and radar parameters. In addition, the embodiment of the present invention is not limited thereto. For a single stealth target, the SBR-PTD method used to calculate the target part is also applicable.

[0060] 2. It can greatly reduce the computational cost with good accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0062] Figure 1 Schematic diagram of various scattering mechanisms of drones.

[0063] Figure 2 Schematic diagram of the composite scattering path of the sea surface and the UAV.

[0064] Figure 3 Schematic diagram of the splitting structure.

[0065] Figure 4 Schematic diagram of dual-scale sea surface geometry.

[0066] Figure 5 Comparison of the reflection coefficients obtained by the method proposed in the present invention and MoM at different incident angles.

[0067] Figure 6 Comparison of reflection coefficients obtained by the method proposed in the present invention and MoM at different frequencies.

[0068] Figure 7 Calculate the monostatic RCS of a cube with an absorbing coating for MLFMM and SBR-PTD.

[0069] Figure 8 The composite monostatic RCS of the cosine facet and the cube with absorber coating is calculated for MLFMM and TSM-SBR-PTD.

[0070] Fig. 9 Comparison of single-station RCS of UAVs with and without absorbing coating and composite scattering from the sea surface. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0072] The present invention provides a method for quickly calculating the RCS of a coating drone under a complex background, comprising the following steps:

[0073] Step 1: Determine the reflection coefficient of a single-layer absorbing material with a perfect electrical conductor (PEC) substrate at different incident angles based on the equivalent transmission line theory:

[0074]

[0075] In the formula,

[0076]

[0077] Wherein, the subscript v represents vertical polarization, h represents horizontal polarization, and the same below; j represents an imaginary unit; d is the coating thickness; θ i represents the incident angle, the subscript i represents the incident field; ε is the relative dielectric constant of the coating, μ is the relative magnetic permeability of the coating; k 0 =2π / λ is the free space wave number.

[0078] When θ i = 0, at this time R v =R h ,Right now:

[0079]

[0080] Step 2: Calculate the induced current generated by the incident electromagnetic wave on the target surface coated with a single layer of absorbing material based on the reflection coefficient, use the geometric optics method to track the triangular surface elements illuminated by the incident wave and the triangular surface elements illuminated by each order of reflected waves, and then use physical optics (PO) and PTD to calculate the scattering field of each illuminated surface element, and superimpose them to obtain the total scattering field of the target. The method for calculating the RCS of a drone target coated with a single layer of absorbing material is:

[0081] When an electromagnetic wave is incident on a target surface coated with multilayer absorbing materials, the unit vector of the initial incident wave direction is The corresponding reflection direction is:

[0082]

[0083] in, is the unit normal vector of the triangular surface element on the target surface illuminated by the electromagnetic wave; The subscript r represents the reflected field, the same below.

[0084] The reflected electric field strength is:

[0085] E r =E i ·R·exp(-jkr)

[0086] Among them, E i is the incident electric field of the electromagnetic wave incident on the surface of the absorbing coating; R is the electric field reflection coefficient R of the surface of the absorbing coating h or R v , can be obtained according to step 1; r is the distance from the upward radar to the target center; k = 2π / λ is the electromagnetic wave number;

[0087] The reflected magnetic field strength is:

[0088]

[0089] The induced electromagnetic currents generated on the target surface are:

[0090]

[0091] Where η is the input impedance of the upper boundary surface of the absorbing coating, and θ is the unit vector of the electromagnetic wave incident on the coating surface. and the unit surface normal vector The angle between them, E h and E v are the horizontal polarization electric field component and the vertical polarization electric field component, and are the unit horizontally polarized wave and vertically polarized wave vectors respectively;

[0092] According to the physical optics method, the scattering field E of the induced current at each reflection is obtained PO for:

[0093]

[0094] in, is the scattered wave unit vector, s is the illuminated target surface area;

[0095] In addition to the specular reflection on the drone surface, the coupled scattering between the drone structural components, and the cavity scattering of the air intake, edge diffraction will also occur at the edges of the drone wings and tail. The physical diffraction theory is used to solve the scattered field of this part. Figure 3 Given the split structure, its far field calculation formula can be expressed as:

[0096]

[0097] Among them, E PTD represents the PTD field, is the tangent unit vector of the edge structure of the UAV wing, tail wing, etc., and r' is the position coordinate of the midpoint of a certain edge of the triangular surface element;

[0098]

[0099] Among them, β i and β s The angle between the incident direction and the scattering direction and the edge; the diffraction coefficient D e , D m and D em It can be expressed as

[0100]

[0101] Among them, φ i ,φ s They represent the azimuth of the incident direction and the scattering direction in the local coordinate system, Q, α 1 and α 2 It is expressed as:

[0102]

[0103] sinα 1 =(sin 2 β i -sin 2 β s cos 2 φ s ) 1 / 2 / sinβ i

[0104] sinα 2 =(sin 2 β i -sin 2 β s cos 2 (nπ-φ s )) 1 / 2 / sinβ i

[0105] Therefore, the total scattered field incident on the target surface can be expressed as:

[0106]

[0107] Among them, the first ∑ represents the superposition of different orders of bouncing rays, and the second ∑ represents the superposition of the far-field scattering field of each order of illuminated triangle facets. They are the PTD fields of the three edges of the triangle surface element respectively.

[0108] Step 3: The scattered field of each facet on the sea surface at a fixed angle can be obtained by vector superposition of the PO' field and the scattered field obtained by TSM. The method is:

[0109] Based on the dual-scale surface element model, the rough sea surface can be regarded as composed of large-scale gravity waves attached to many small-scale capillary waves, and the small-scale capillary waves are tilted according to the distribution of large-scale waves. Its geometric diagram is shown in the figure below. Figure 4 shown. represents the global coordinate system, represents the local coordinate system of the small surface element on the rough sea surface, represents the global angle, Represents the local angle.

[0110] Therefore, the perturbation theory can be used to calculate the scattering coefficient of small-scale capillary waves, and the Kirchhoff approximation (KA) method can be used to calculate the scattering coefficient of large-scale gravity waves. In order to derive the scattering contribution of an arbitrarily tilted small facet, a local coordinate system is established on the facet:

[0111]

[0112] in, is the unit normal vector of the small face.

[0113] When electromagnetic waves are irradiated nearly vertically onto the rough sea surface, the mirror reflection of large-scale gravity waves is the main source of scattering. In this case, the KA method can be used to calculate its scattering coefficient:

[0114]

[0115] in, is the unit incident wave vector, k is the electromagnetic wave number, is the joint probability density function. and is the slope of the tangent plane at the mirror point; polarization factor of the KA method It can be expressed as:

[0116]

[0117] in, In the global coordinate system and The corresponding polarization unit vector; R v and R h The Fresnel reflection coefficient under two polarization modes can be expressed as:

[0118]

[0119] Here, ε is the relative dielectric constant calculated by the Debye model.

[0120] It is worth mentioning that when using SBR to calculate the coupling field between the sea surface and the UAV, the usual practice is to treat the sea surface element as a smooth plane. However, in high sea conditions, the sea surface element has a certain degree of roughness. For slightly rough surfaces or smooth planes, it is reasonable to assume that the reflected energy is mainly concentrated along the mirror reflection direction. However, for very rough surfaces, such as in strong winds or high frequencies, the diffuse reflection components in all directions usually dominate, while the mirror reflection components can be ignored. Therefore, R h and R vThe above formula cannot be used. In this case, the scattered field of the sea surface is expressed as E PO' , where the reflection coefficient in the above equation can be rewritten as:

[0121] R v '=R v ·ρ s

[0122] R' h =R h ·ρ s

[0123] in,

[0124]

[0125] Among them, ρ s is the rough surface reflection factor, τ=σ h cosθ / λ, λ is the wavelength of the incident wave, σ h is the height standard deviation, which is related to the sea surface wind speed U:

[0126] σ h =0.0051U 2

[0127] The scattering coefficient of an arbitrarily inclined micro-rough surface element can be calculated by the following formula:

[0128]

[0129] Among them, S ζ (q l ) represents the power spectrum function of the micro-rough surface element. represents the polarization factor in the global coordinate system, that is:

[0130]

[0131] in, is the polarization unit vector corresponding to the incident and scattered unit vectors in the local coordinate system. Its relationship with the global polarization unit vector can be expressed as:

[0132]

[0133] in,

[0134]

[0135] Therefore, the total field of the two-scale sea surface scattering model can be expressed as:

[0136]

[0137] Where r is the distance from the upward radar to the center of the sea surface, and the phase term It can be expressed as:

[0138]

[0139] Among them, ξ∈[-1 / 2,1 / 2], Represents the maximum phase difference within the bin, r mn is the position vector of each face element relative to the origin of the coordinate system, Δρ mn =q·r mn is the phase delay caused by the relative position of each element.

[0140] Step 4: For the composite scene of sea surface and UAV, for each triangular facet of the UAV, the far-field scattering is composed of the PO field E from the triangular facet surface PO and the PTD field E from the three edges of the triangle element PTD The direct scattering of the sea surface can be obtained by TSM. The coupled scattering field between the sea surface and the UAV comes from the PO field of the triangular surface element of the aircraft surface or the PO' field of the triangular surface element of the sea surface. PO' ,Right now:

[0141]

[0142] Among them, the first ∑ represents the superposition of bounce rays of different orders, and the second ∑ represents the superposition of the far-zone scattered fields of each order of illuminated triangles.

[0143] Therefore, the total field RCS of the complex sea background and UAV composite model can be expressed as:

[0144]

[0145] Step 5: In order to improve the computational efficiency, the above algorithm is accelerated by MPI (Massage passing interface) parallel computing. The parallel computing environment is MSMPI under Windows system. At the same time, this project intends to use OptiX to accelerate the ray tracing process. OptiX is a ray tracing API launched by NVIDIA, which can maximize the use of GPU resources.

[0146] The following is a detailed description of the effects of this application in conjunction with simulation:

[0147] First, the proposed reflection coefficient is verified by the method of moments (MoM) in Feko. A unit physical model is established in Feko, and then periodic boundary conditions are used to simulate the reflection of an infinite periodic plate. The size of the plate is 0.2m×0.2m, the relative dielectric constant of the absorbing coating is ε=(15.326,0.534), the relative magnetic permeability is μ=(2.3164,1.927), the coating thickness is 1.5mm, and the incident wave frequency is f=3GHz. Figure 5 A comparison of the reflection coefficients of the method proposed in the present invention and MoM is given. Figure 5 It can be seen that the results of the method proposed in the present invention show good consistency with those of MoM. Figure 6 The curves of the reflection coefficient of the method proposed in the present invention and MoM as a function of the incident wave frequency are given. The incident angle is 0°, and the results are in good agreement. Figure 5 and Figure 6 All of these have proven the accuracy of the method proposed in the present invention.

[0148] Then, the single-station RCS of the cube with absorbing coating is calculated by multilevel fast multipole method (MLFMM) and SBR-PTD, respectively. Figure 7 As shown. The incident frequency is 10GHz, the relative dielectric constant is ε=(15.326,0.534), the relative magnetic permeability is μ=(2.3164,1.927), the coating thickness is 1.5mm, and the cube size is 0.6m×0.6m×0.6m. Figure 7 It can be seen that the two curves are in good agreement, indicating the effectiveness of the algorithm proposed in the present invention. This also shows that the present invention is also applicable to calculating the RCS of a single coated target.

[0149] Then, the composite monostatic RCS of the cosine facet and the cube with absorbing coating is calculated using MLFMM and TSM-SBR-PTD, respectively. Figure 8 As shown. The size of the cosine small facet is 0.9m×0.9m, the dielectric constant is ε=(68.9337,41.7395), the relative dielectric constant of the coated cube is ε=(15.326,0.534), the relative magnetic permeability is μ=(2.3164,1.927), the coating thickness is 1.5mm, the cube is located 0.03m above the curved surface, and its size is 0.1m×0.1m×0.1m. Figure 8 It can be seen that the results calculated by MLFMM and TSM-SBR-PTD are in good agreement, which demonstrates the effectiveness of the algorithm proposed in this invention.

[0150] Finally, the proposed method is used to calculate the RCS of the composite scene of the sea surface and the UAV coated with absorbing materials, and the simulation results are compared with the same PEC UAV, such as Fig. 9 As shown. The incident frequency is 10GHz, the pitch angle is -90°~90°, and the azimuth angle is 90°; the sea surface wind speed is 6m / s, the sea surface size is 64m×64m, and the sea surface dielectric constant is ε=(59.06,34.927); the UAV is located 3m above the sea surface, the UAV is about 8.4m long, the wingspan is about 7.4m, the relative dielectric constant of the absorbing coating is ε=(15.326,0.534), and the relative magnetic permeability is μ=(2.3164,1.927). The simulation results show that when the pitch angle is near 0°, the composite RCS of the sea surface and the UAV decreases significantly, while there is almost no decrease near low grazing angles. This is because when the electromagnetic wave is incident at a low grazing angle, the scattering of the sea surface accounts for the main contribution, while the coupled scattering between the target and the sea surface accounts for the main contribution near 0°. After the target surface is coated with absorbing materials, the reduction of the composite RCS is significantly reduced. It can be seen that the radar absorbing coating can effectively reduce the RCS of the target. In addition, in order to improve the computational efficiency, the simulation algorithm is accelerated by MPI parallel computing. The CPU configured on the computing server is AMD EPYC 9654 96-Core Processor, NVIDIA 3080, and the memory is 16GB*12DDR5. Table 1 gives the computational Fig. 9 The time consumption of the simulation algorithm proposed in this invention under serial and parallel computing is compared in the scenario corresponding to the target with radar absorbing coating, where the number of CPU processes in parallel computing is set to 80. It can be seen that after CPU+GPU acceleration, the computing efficiency is significantly improved.

[0151] Table 1 The simulation algorithm proposed in this invention Fig. 9 Comparison of serial and parallel computing time in corresponding scenarios

[0152] Acceleration method Time(s) Not accelerated 2479.50 CPU+GPU 53.08

[0153] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A method for quickly calculating the RCS of a coating drone under complex background, characterized in that: include: Step 1: Determine the reflection coefficient of the single-layer absorber with PEC substrate at different incident angles according to the equivalent transmission line theory; Step 2: Calculate the induced current generated by the incident electromagnetic wave on the target surface coated with a single layer of absorbing material according to the reflection coefficient; use the geometric optics method to track the triangular surface elements illuminated by the incident wave and the triangular surface elements illuminated by each order of reflected waves, calculate the scattering field of each illuminated surface element based on the induced current using physical optics and physical diffraction theory, and superimpose the calculated scattering fields; Step 3: For the scattered field of each surface element on the sea surface model at a fixed angle, use E PO' The field and the scattered field obtained by TSM are obtained by vector superposition; Step 4: For the composite scene of sea surface and UAV, for each triangular facet of the UAV, the far-field scattering is composed of the PO field E from the triangular facet surface PO and the PTD field E from the three edges of the triangle element PTD The direct scattering of the sea surface can be obtained by TSM. The coupled scattering field between the sea surface and the UAV comes from the PO field of the triangular surface element of the aircraft surface or the PO' field of the triangular surface element of the sea surface. PO' ,Right now: Among them, the first Σ represents the superposition of different orders of bouncing rays, and the second Σ represents the superposition of the far-zone scattered fields of each order of illuminated triangles; They are the PTD fields of the three edges of the triangle surface element; Step 5: Based on E total Get the total field RCS of the complex sea background and UAV composite model: Where R is the reflection coefficient.

2. According to claim 1, a method for quickly calculating the RCS of a coating drone under complex background, characterized in that: Reflection coefficient from step 1: In the formula, Wherein, the subscript v represents vertical polarization, h represents horizontal polarization, and the same below; j represents an imaginary unit; d is the coating thickness; θ i represents the incident angle, the subscript i represents the incident field; ε is the relative permittivity of the coating, μ is the relative magnetic permeability of the coating; k0 = 2π / λ is the free space wave number; When θ i = 0, at this time R v =R h ,Right now:

3. According to claim 1, a method for quickly calculating the RCS of a coating drone under complex background, characterized in that: Based on the induced current, physical optics is used to calculate the scattered field of each surface element. The formula used is: in, is the scattered wave unit vector, Δs is the illuminated target surface area, r is the distance from the upward radar to the target center, k = 2π / λ is the electromagnetic wave number, η is the input impedance of the upper boundary surface of the absorbing coating, E h and E v are the horizontal polarization electric field component and the vertical polarization electric field component, and are the unit horizontal polarization wave and vertical polarization wave vector respectively, J is the induced current, and M is the induced magnetic current.

4. According to claim 1, a method for quickly calculating the RCS of a coating drone under complex background, characterized in that: Based on the induced current, the physical diffraction theory is used to calculate the scattered field of each illuminated surface element. The formula used is: in, is the tangent unit vector of the edge structure of the UAV wing, tail wing, etc., r' is the position coordinate of the midpoint of a certain edge of the triangular surface element, β i and β s The angle between the incident direction and the scattering direction and the edge, D e , D m and D em is the diffraction coefficient, E i is the incident electric field of the electromagnetic wave incident on the surface of the absorbing coating, H i is the incident magnetic field when the electromagnetic wave is incident on the surface of the absorbing coating.

5. According to claim 1, a method for quickly calculating the RCS of a coating drone under complex background, characterized in that: The step 3 is specifically as follows: in, Among them, ρ s is the rough surface reflection factor, τ=σ h cosθ / λ, λ is the wavelength of the incident wave, σ h is the height standard deviation, which is related to the sea surface wind speed U: s h =0.0051U 2 The scattering coefficient of an arbitrarily inclined micro-rough surface element can be calculated by the following formula: Among them, S ζ (q l ) represents the power spectrum function of the micro-rough surface element; represents the polarization factor in the global coordinate system, that is: in, is the polarization unit vector corresponding to the incident and scattered unit vectors in the local coordinate system. Its relationship with the global polarization unit vector can be expressed as: in, Therefore, the total field of the two-scale sea surface scattering model can be expressed as: Where r is the distance from the upward radar to the center of the sea surface, and the phase term It can be expressed as: Among them, ξ∈[-1 / 2,1 / 2], Represents the maximum phase difference within the bin, r mn is the position vector of each face element relative to the origin of the coordinate system, Δρ mn =q·r mn is the phase delay caused by the relative position of each element.

6. According to claim 1, a method for quickly calculating the RCS of a coating drone under complex background, characterized in that: The above method uses MPI parallel computing for acceleration, and the parallel computing environment is MSMPI under the Windows system.

7. A computer system, characterized in that include: One or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the method of claim 1.

8. A computer-readable storage medium, characterized in that Computer executable instructions are stored, and when the instructions are executed, they are used to implement the method of claim 1.

9. A computer program product, characterized in that The invention comprises computer executable instructions, which are used to implement the method of claim 1 when being executed.

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