A foil strip cloud echo simulation modeling method

Abstract

This invention discloses a method for simulating and modeling chaff cloud echoes, comprising: calculating the full-space single-base scattering characteristics of individual chaff strips of different lengths using the Pocklington integral equation; generating the scattering characteristics of each chaff strip using Lagrange interpolation based on a randomly generated or existing chaff cloud model; obtaining the echo of each chaff strip according to the relative position between the detector and the chaff strip, combined with radar equations, and vector-superimposing the echo contributions of all chaff strips to form the overall echo of the chaff cloud; and calculating the echo characteristic curve of each sampling point on the detector's motion trajectory one by one according to the above steps. This invention considers the scattering of chaff strips from the perspective of the scattering center, enabling efficient simulation of chaff cloud echo characteristics, and meeting current engineering requirements in terms of both accuracy and speed.

Description

Technical Field

[0001] This invention relates to radar target characteristic simulation technology, and more particularly to a chaff cloud echo simulation modeling method. Background Technology

[0002] The traditional low-frequency modeling method for chaff cloud echo simulation is computationally inefficient for engineering applications. On one hand, the number of chaff bars in a chaff cloud can reach millions, making the computational complexity enormous. On the other hand, low-frequency modeling methods are computationally expensive in terms of both time and space. Furthermore, obtaining chaff cloud echo characteristics through testing is extremely cost-inefficient and makes random statistical analysis impossible. Summary of the Invention

[0003] The purpose of this invention is to provide a method for simulating and modeling the echo of chaff clouds. By using the Pocklington integral equation to obtain the scattering characteristics of a single chaff, and combining the position and attitude of existing chaff clouds with radar equations, a rapid simulation of the echo characteristics of chaff clouds can be achieved, which can meet the current engineering requirements in terms of both accuracy and speed.

[0004] To achieve the above objectives, the present invention provides a method for simulating and modeling foil cloud echoes, comprising the following steps:

[0005] Step S1: Calculate the full-space single-base scattering characteristics of single foil strips of different lengths using the Pocklington integral equation;

[0006] Step S2: Based on a randomly generated or existing chaff cloud model, Lagrange interpolation is used to generate the scattering characteristics of each chaff according to its orientation.

[0007] Step S3: Combine the radar equations to obtain the echo of each chaff strip, and vector superimpose the echo contributions of all chaff strips to form the overall echo of the chaff cloud;

[0008] Step S4: Repeat the calculation process of steps S1 to S3 for each sampling point on the detector's motion trajectory, and merge them to form the echo on the entire trajectory.

[0009] Preferably, step S1 includes: using a line model to discretize the foil strip into line segments, and using the method of moments to solve the Pocklington integral equation to obtain the single-base scattering characteristics. To ensure the accuracy of interpolation in step S2, the single-base scattering characteristics are sampled at high density in the elevation and azimuth directions.

[0010] Preferably, step S2 includes: at a certain time sampling point, calculating the angle θ between the chaff and the vertical axis based on the attitude of the chaff in the chaff cloud, and calculating the scattering characteristics based on Lagrange interpolation. (Considering the axisymmetry of foil scattering, one-dimensional interpolation is sufficient), expressed as follows:

[0011]

[0012] In the formula, The scattering characteristics are known in step S1.

[0013] Preferably, step S3 includes: based on the radar equation, the overall echo voltage of the chaff cloud is calculated as follows:

[0014]

[0015] In the formula, λ is the wavelength, and G T G R These represent the transmit and receive antenna gains, R. m σ represents the distance from the detector to the center of the chaff strip, p is the emitted waveform from the detector, and σ is the scattering characteristic of a single chaff strip. i This is a function of the foil's attitude.

[0016] Preferably, step S4 includes: the echo voltage of each sampling point on the detector's motion trajectory has no data communication and is independent of each other, which can be efficiently accelerated by multi-core parallel computing.

[0017] The present invention has the following advantages:

[0018] This invention has extremely high efficiency in solving fully diffused foil cloud echoes, and the simulation time is improved by orders of magnitude compared with the accurate low-frequency modeling method.

[0019] This invention is applicable to echo simulation in both far-field and near-field conditions of foil clouds: in the far-field condition, the electric field intensity of each foil strip is the same; in the near-field condition, the electric field intensity of each foil strip is determined by the gain.

[0020] This invention can be modified and applied to the simulation calculation of dense foil clouds. The Pocklington integral equation has extremely high calculation efficiency and can be grouped according to the distance between dense foils to accelerate the calculation.

[0021] The echo calculation method in this invention can be extended to the simulation calculation of continuous targets. Unlike the table lookup method for chaff, continuous targets require the calculation of the scattering intensity of each discrete unit, and then the synthesis of the echo. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the scattering characteristics of a single foil strip provided in an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the foil posture definition provided in an embodiment of the present invention. Detailed Implementation

[0024] As mentioned in the background section, there is currently no efficient simulation modeling method for chaff cloud echoes. Research has shown that Beijing Institute of Technology, in its patent "A Method for Modeling the Scattering Center of Chaff" (Publication No.: CN113281708A), uses triangular facets to divide the chaff and obtains a chaff scattering center parameter model containing size information through fitting, thereby calculating the scattered field echo. Xi'an University of Electronic Science and Technology, in its patent "A Real-Time Simulation Method for Chaff Cloud Radar Echoes Based on FPGA" (Publication No.: CN112578352A), uses an FPGA platform for hardware optimization to simulate the radar echoes of multiple chaff clouds. Simultaneously, in its patent "A Fast Calculation Method for Chaff Cloud Scattering Based on Impedance Matrix Blocking" (Publication No.: CN112733364A), the chaff cloud is divided into several subdomains according to the actual situation, and the current matrix of each region is calculated in parallel to accelerate the solution.

[0025] Of the three patents mentioned above, the first patent faces challenges in both accuracy and difficulty in establishing the scattering center parameter model. The second patent ignores the attitude effect of the foil, directly resulting in low computational accuracy. The third patent employs the traditional impedance matrix block method, which cannot balance computational scale and efficiency.

[0026] In the publicly available literature, DWSeo, in his IEEE journal paper "Dynamic RCS Estimation of Chaff Clouds," used aerodynamic methods to simulate the diffusion process of chaff clouds and employed equivalent medium theory to perform electromagnetic scattering calculations. TWWinchester, in his IEE Proceedings paper "Pulsed Radar Return from a Chaff Cloud," used the Monte Carlo stochastic method combined with radar equations to perform echo simulation calculations. SWMarcus, in his IEEE journal paper "Electromagnetic Wave Propagation Through Chaff Clouds," also used equivalent medium theory to simplify the calculation process of radio wave propagation. The calculation methods used in these three papers are low-frequency, stochastic, and analytical derivations, respectively, which differ from the methods used in this invention.

[0027] There is an urgent need to propose a simulation modeling method for chaff cloud echoes, and at the same time, to propose a fast echo simulation calculation method based on obtaining the full-space scattering characteristics of a single chaff strip and combining radar equations, so as to solve the problems in the background technology.

[0028] This invention proposes a fast echo simulation calculation method based on obtaining the full-space scattering characteristics of a single foil strip and combining radar equations, which can meet the current engineering requirements in terms of both accuracy and speed.

[0029] The following is based on Figure 1 and Figure 2 The preferred embodiments of the present invention will be described in detail below.

[0030] like Figure 1 and Figure 2 The diagram shown is a schematic representation of the foil attitude definition in one embodiment of the present invention. The present invention provides a method for simulating and modeling foil cloud echoes, comprising the following steps:

[0031] Step S1: Calculate the full-space single-base scattering characteristics of single foil strips of different lengths using the Pocklington integral equation.

[0032] Specifically, step S1 includes: discretizing the foil strip into line segments using a line model, and solving the Pocklington integral equation using the method of moments to obtain the single-base scattering characteristics. To ensure the accuracy of interpolation in step S2, the single-base scattering characteristics are sampled at high density in both the elevation and azimuth directions. Figure 1 The image shows the full-space scattering characteristics of a 10 GHz half-wavelength foil.

[0033] Step S2: Based on a randomly generated or existing foil cloud model, Lagrange interpolation is used to generate the scattering characteristics of each individual foil strip according to its orientation.

[0034] Specifically, step S2 includes: at a certain time sampling point, calculating the angle θ between the chaff and the vertical axis based on the attitude of the chaff in the chaff cloud, and calculating the scattering characteristics based on Lagrange interpolation. (Considering the axisymmetry of foil scattering, one-dimensional interpolation is sufficient), expressed as follows:

[0035]

[0036] In the formula, The scattering characteristics are known in step S1.

[0037] Step S3: Combine the radar equations to obtain the echo of each chaff strip, and vector superimpose the echo contributions of all chaff strips to form the overall echo of the chaff cloud.

[0038] Specifically, step S3 includes: based on the radar equation, the overall echo voltage of the chaff cloud is calculated as follows:

[0039]

[0040] In the formula, λ is the wavelength, and G T G R These represent the transmit and receive antenna gains, R. m σ represents the distance from the detector to the center of the chaff strip, p is the emitted waveform from the detector, and σ is the scattering characteristic of a single chaff strip. i This is a function of the foil's attitude. Figure 2 R is given m Definition of foil attitude.

[0041] Step S4: Repeat the calculation process of steps S1 to S3 for each sampling point on the detector's motion trajectory, and merge them to form the echo on the entire trajectory.

[0042] Specifically, step S4 includes: using multi-core parallel computing to compute the echoes at each sampling point on the detector's motion trajectory. The computation of the echo at each sampling point is independent, with no data interaction, and the parallel computing efficiency can achieve linear acceleration.

[0043] The present invention has the following advantages:

[0044] This invention has extremely high efficiency in solving fully diffused foil cloud echoes, and the simulation time is improved by orders of magnitude compared with the accurate low-frequency modeling method.

[0045] This invention is applicable to echo simulation in both far-field and near-field conditions of foil clouds: in the far-field condition, the electric field intensity of each foil strip is the same; in the near-field condition, the electric field intensity of each foil strip is determined by the gain.

[0046] This invention can be modified and applied to the simulation calculation of dense foil clouds. The Pocklington integral equation has extremely high calculation efficiency and can be grouped according to the distance between the dense foils to accelerate the calculation.

[0047] The echo calculation method in this invention can be extended to the simulation calculation of continuous targets. Unlike the table lookup method for chaff, continuous targets require the calculation of the scattering intensity of each discrete unit, and then the synthesis of the echo.

[0048] It should be noted that, in the embodiments of the present invention, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for simulating and modeling the echo of a foil cloud, characterized in that, Includes the following steps: Step S1: Calculate the full-space single-base scattering characteristics of single foil strips of different lengths using the Pocklington integral equation; Step S2: Based on a randomly generated or existing chaff cloud model, Lagrange interpolation is used to generate the scattering characteristics of each chaff according to its orientation. Step S3: Combine the radar equations to obtain the echo of each chaff strip, and vector superimpose the echo contributions of all chaff strips to form the overall echo of the chaff cloud; Step S4: Repeat the calculation process of steps S1 to S3 for each sampling point on the detector's motion trajectory, and merge them to form the echo on the entire trajectory. Step S1 includes: using a line model, discretizing the foil into line segments, and using the method of moments to solve the Pocklington integral equation to obtain the single-base scattering characteristics; The single-base scattering characteristics are sampled at high density in both the pitch and azimuth directions; Step S2 includes: at a certain time sampling point, calculating the angle θ between the chaff and the vertical axis based on the attitude of the chaff in the chaff cloud, and calculating the scattering characteristics using Lagrange interpolation. Expressed as: In the formula, The scattering characteristics already known in step S1; Step S3 includes: Based on the radar equation, the overall echo voltage of the chaff cloud is calculated as follows: In the formula, λ is the wavelength, and G T G R These represent the transmit and receive antenna gains, R. m The distance from the detector to the center of the chaff is given by ρ, where p is the emitted waveform from the detector, and ρ represents the scattering characteristics of a single chaff strip. This is a function of the foil's attitude.

2. The foil cloud echo simulation modeling method as described in claim 1, characterized in that, Step S4 includes: using multi-core parallel computing to calculate the echo of each sampling point on the motion trajectory of the detector.

Images