Analysis method for time-domain scattering characteristics of chaff cloud based on modulated gaussian pulse radar

Abstract

The application discloses a kind of foil cloud cluster time-domain scattering characteristic analysis method based on modulated Gaussian pulse radar, specifically includes: the size of foil cloud cluster, the number of foil, length, radius, position coordinate, attitude angle are determined by Matlab;Foil cloud cluster modeling is completed using the method of Matlab-CST joint simulation;The scattering characteristics of foil cloud cluster are analyzed using finite integration algorithm, and the time-domain echo of foil cloud cluster is obtained;Change receiving angle, obtain the time-domain echo of foil cloud cluster from the same angle incidence at different angles receiving electromagnetic wave.The application completes foil cloud cluster modeling by the method of Matlab-CST joint simulation, and the time-domain echo of foil cloud cluster is obtained by time-domain finite integration algorithm, fully considers the influence of randomness and overlapping of foil distribution on time-domain echo.

Description

TECHNICAL FIELD

[0001] The present application relates to electromagnetic and microwave technology, in particular to a chaff cloud time domain scattering characteristic analysis method based on modulated Gaussian pulse radar. BACKGROUND

[0002] Under the complex electromagnetic environment on the battlefield, chaff jamming against radar is the most common means, and time domain signal is the basis for radar to identify targets. Electromagnetic wave adopts modulated Gaussian pulse signal, Gaussian pulse signal is an important simplified model, which can be used to simulate various statistical signal models, has strong transmission performance and anti-interference ability. Compared with Gaussian pulse, the center frequency of modulated Gaussian pulse has a shift, no longer contains zero frequency component, and the generation and processing of modulated Gaussian pulse are relatively simple and mature in technology, so the modulated Gaussian pulse signal is selected as the excitation signal in the present application.

[0003] Because it is difficult to calculate the transient electromagnetic field of large and complex targets, and there are few and single content researches on the electromagnetic characteristics of large and complex targets, the existing researches on the time domain echo of chaff cloud are all in the form of mathematical modeling and signal processing, without fully considering the influence of the shielding effect, blocking effect and shielding effect of chaff distribution and overlapping on radar signal. Therefore, the present application starts from reality, fully considers the influence of chaff distribution and overlapping on time domain scattering characteristics, and obtains relatively real chaff cloud time domain echo through the finite integration time domain method (FIT). SUMMARY

[0004] The present application aims to provide a chaff cloud time domain scattering characteristic analysis method based on modulated Gaussian pulse radar.

[0005] The technical solution for realizing the present application is as follows: in the first aspect, the present application provides a chaff cloud time domain scattering characteristic analysis method based on modulated Gaussian pulse radar, including the following steps:

[0006] Determine the size, number, length, radius, coordinates and attitude angle of chaff cloud in Matlab;

[0007] Establish a chaff cloud model through Matlab-CST joint simulation;

[0008] Obtain chaff cloud time domain echo through the finite integration time domain algorithm;

[0009] Change the receiving angle to obtain chaff cloud time domain echo received at different angles when electromagnetic wave is incident at the same angle.

[0010] In the second aspect, the present application provides an electronic device, which includes a memory, a processor and a computer program stored in the memory and capable of running on the processor, and the processor realizes the steps of the method in the first aspect when executing the program.

[0011] In a third aspect, the present application provides a computer readable storage medium, having stored thereon a computer program which, when executed by a processor, implements the steps of the method of the first aspect.

[0012] Compared with the prior art, the present application has the following advantages: Matlab and CST are combined for simulation, so that the modeling time of a large number of high-density chaff clouds in CST is shortened; the time-domain echo of the chaff cloud is analyzed in CST, so that the influence of the shielding effect, blocking effect and shielding effect of the chaff cloud on the echo signal can be fully considered; the excitation signal is incident from the same angle and received at different angles, so that the characteristics of the echo signal at different receiving angles can be analyzed according to the simulation results. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a flow chart of the method for analyzing the time-domain scattering characteristics of the chaff cloud based on the modulated Gaussian pulse radar.

[0014] Figure 2 It is a time-domain and frequency-domain waveform diagram of the electromagnetic wave.

[0015] Figure 3 It is a chaff cloud model in CST.

[0016] Figure 4 It is a time-domain echo of the chaff cloud. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0018] A method for analyzing the time-domain scattering characteristics of a chaff cloud based on a modulated Gaussian pulse radar, comprising the following steps:

[0019] Step 1: determining the size, number, length, radius, coordinates and attitude angle of the chaff cloud in Matlab;

[0020] Step 2: establishing a chaff cloud model by Matlab-CST joint simulation;

[0021] Step 3: obtaining the time-domain echo of the chaff cloud by the finite-difference time-domain algorithm;

[0022] Step 4: changing the receiving angle to obtain the time-domain echo of the chaff cloud when the electromagnetic wave is incident from the same angle and received at different angles.

[0023] The above steps 1-4 are specifically analyzed as follows:

[0024] The length and radius of a single foil strip can be determined for a foil cloud, and in the case of a large number of foil strips, the position coordinates, attitude azimuth angle and attitude inclination angle of the foil strips satisfy certain distributions.

[0025] In order to facilitate modeling, the foil cloud is divided into several regions, and the foil coordinates are uniformly distributed in each region, and the distribution equation is as follows:

[0026]

[0027] In the formula, (x, y, z) is the three-dimensional coordinates of the foil, r is the distance from the foil to the center of the foil cloud, θ is the spherical latitude coordinate, is the spherical longitude coordinate. If the radius of the foil cloud in the region is R, r, θ, respectively satisfy the uniform distribution of (0, R), (0, π) and (0, 2π).

[0028] The attitude azimuth angle θ c obeys the uniform distribution on [0, 2π], and the attitude inclination angle obeys the bimodal normal distribution, and the distribution equation is as follows:

[0029]

[0030] In the formula, θ d and π-θ d are the attitude inclination angle distribution centers, D is the normal distribution standard deviation, and ξ satisfies:

[0031]

[0032] In order to analyze the influence of other factors on the time-domain echo of the foil cloud in the subsequent analysis, it is necessary to determine the attitude distribution of a single foil in the air. The foil attitude distribution has spherical uniform distribution, horizontal normal distribution, vertical normal distribution and bimodal inclined normal distribution. The standard deviation D and θ d of the four distributions are as shown in Table 1:

[0033] Table 1 Foil attitude distribution

[0034]

[0035] In the modeling process, model 2-horizontal normal distribution is selected, and the simulation parameters are as shown in the following table:

[0036] Table 2 Simulation parameters

[0037] Foil strip length 72 mm Foil strip radius 7.2 mm Foil strip cloud radius 1.5m Foil strip number 30,000 Incident wave frequency 2-3 GHz Incident wave duration 7.1 ns

[0038] Figure 1 is the flowchart of the present application, Figure 2The time-domain and frequency-domain waveform graphs of the incident wave show that the center frequency f0 of the incident wave is 2.5 GHz.

[0039] The foil cloud model is established by Matlab-CST joint simulation, specifically including: the invoke() function can realize Matlab and CST joint debugging, automatic simulation can be realized in CST through VB code, Matlab code is converted into corresponding VB code to realize the creation of microwave studio, new CST file and other file initialization operations, and the information of the length unit, frequency unit and time unit of the microwave studio is determined. The material, position information, length, radius, azimuth angle, attitude inclination angle of the single foil and the size of the foil cloud are imported into CST to complete the modeling of the foil cloud.

[0040] The following three statements are respectively: load CST; create a new MWS project; create a new CST file.

[0041] CST=actxserver('CSTStudio.application');

[0042] mws=invoke(CST,'NewMWS');

[0043] invoke(mws,'FileNew');

[0044] The length unit of the microwave studio is determined to be mm, the frequency unit is GHz, and the time unit is ns, and the related statements are as follows: sCommand=”;

[0045] sCommand=[sCommand'With Units'];

[0046] sCommand=[sCommand 10'.Geometry"mm"'];

[0047] sCommand=[sCommand 10'.Frequency"ghz"'];

[0048] sCommand=[sCommand 10'.Time"ns"'];

[0049] sCommand=[sCommand 10'End With'];

[0050] invoke(mws,'AddToHistory','define units',sCommand);

[0051] The modeling process for a cylindrical foil strip, made of PEC, begins by determining the outer and inner diameters. The axis of the cylindrical foil strip corresponds to the z-axis, thus determining its position coordinates. The modeling process for the cylindrical foil strip includes the following statements:

[0052] sCommand=[sCommand 10'.Axis"',Axis,''"'];

[0053] sCommand=[sCommand 10'.OuterRadius"',num2str(OuterRadius,2),'"'];

[0054] sCommand=[sCommand 10'.InnerRadius"',num2str(InnerRadius,2),'"'];

[0055] sCommand=[sCommand 10'.Xcenter"',int2str(Xcenter),'"'];

[0056] sCommand=[sCommand 10'.Ycenter"',int2str(Ycenter),'"'];

[0057] sCommand=[sCommand 10'.Zrange"',int2str(Zrange-36),'","',int2str(Zrange+36),'"'];

[0058] sCommand=[sCommand 10'.Create'];

[0059] sCommand=[sCommand 10'End With'];

[0060] The Finite-Time Integral (FIT) algorithm is used to obtain the time-domain echo of chaff clouds. Specifically, the FIT method is based on Maxwell's integral equations.

[0061]

[0062]

[0063]

[0064]

[0065] in Represents electric field strength. Represents magnetic field strength. Represents magnetic flux density, Represents electric displacement.

[0066] The finite-time integral algorithm solves the Maxwell integral equation numerically by discretizing it, using a base network G and an adjoint network. By discretizing the Maxwell integral equations spatially, we obtain the expression for the finite-time integration method as follows:

[0067]

[0068] In the formula, e is the voltage, d is the electric flux, b is the magnetic flux, and S and And C and For the corresponding base network and adjoint network, the following equation also applies. Compared to the analytical form of Maxwell's equations, the discretization of the finite-time integral algorithm does not introduce any approximation conditions, ensuring that the curl divergence and gradient curl in the analytical form are always zero and remain completely unchanged in the grid space. Therefore, the accuracy is greatly improved, as shown in the following equation:

[0069]

[0070] The finite-time integral algorithm is based on Maxwell's grid equations. It replaces the time derivative with the central difference to obtain explicit equations. Its stability must satisfy the CFL stability condition.

[0071] By changing the receiving angle, time-domain echoes of chaff clouds received from different angles when electromagnetic waves are incident from the same angle are obtained. Specifically, because the distribution of chaff in the chaff cloud is random and overlapping, time-domain echoes of chaff clouds with different distributions will be generated at different receiving angles.

[0072] Figure 3 The model is a foil cloud in CST, with a radius of approximately 1.5m and 30,000 foil strips.

[0073] Figure 4 The simulation results show the time-domain scattered echoes of the chaff cloud at different receiving angles. The peak echo positions on the time axis are 12.37 ns, 9.826 ns, and 11.28 ns, with the number of peaks decreasing as the peaks appear. The location and number of peaks vary, indicating that the chaff distribution is uneven, resulting in strong scattering points at different locations. When the excitation signal is incident at the same angle and received at different angles, the overlap of the chaff distribution varies, causing beam obstruction and affecting the time-domain echo distribution of the chaff cloud.

Claims

1. A method for analyzing time-domain scattering characteristics of a chaff cloud based on modulated Gaussian pulse radar, characterized in that, The method comprises the following steps: Determine the size of the chaff cloud, the number, length, radius, coordinates, and attitude angle of the chaff in Matlab; The Matlab-CST joint simulation is used to establish a chaff cloud model; the invoke() function is used to realize the Matlab-CST joint debugging, and the automatic simulation is realized through the VB code in CST; the Matlab code is converted into the corresponding VB code to realize the creation of a microwave studio, the initialization operation of a new CST file, and the determination of the length unit, frequency unit, and time unit information of the microwave studio; the material, position, length, radius, azimuth angle, and attitude inclination angle of the chaff are imported into CST to complete the modeling of the chaff cloud; The time-domain echo of the chaff cloud is obtained through the finite-difference time-domain algorithm; the finite-difference time-domain algorithm is based on the Maxwell integral equation and realizes the discretization without introducing any approximate conditions, guarantees that the divergence of the rotation is zero and the gradient of the rotation is zero in the analytical form, and completely remains unchanged in the grid space, as shown in the following formula: wherein is the electric field intensity, is the magnetic field intensity, is the electric current, is the magnetic flux density, is the electric displacement, q is the electric charge. The finite-difference time-domain algorithm is a numerical solution to Maxwell's integral equations by discretization, and the expression of the finite-difference time-domain algorithm is obtained by the basis network G and the adjoint network The spatial discretization of Maxwell's integral equation is realized, and thus the expression of the finite-difference time-domain algorithm is obtained. where e is the electric field, d is the electric flux, b is the magnetic flux, S and C and are the corresponding base network and the accompanying network; The finite-difference time-domain algorithm is based on the Maxwell grid equation set, uses the central difference to replace the time derivative, obtains an explicit equation, and the stability must satisfy the CFL stability condition; The receiving angle is changed to obtain the time-domain echo of the chaff cloud when the electromagnetic wave is incident at the same angle and received at different angles. The cylindrical chaff is selected, the chaff cloud is divided into several regions, and the chaff coordinates are uniformly distributed in each region; the distribution equation is as shown in the following formula:

2. The method according to claim 1, wherein, The chaff attitude distribution includes spherical uniform distribution, horizontal normal distribution, vertical normal distribution, and double-inclined normal distribution. where (x, y, z) is the foil strip three-dimensional coordinates, r is the distance from the foil strip to the center of the foil cloud, θ is the spherical coordinate, is the spherical coordinate; if the radius of the foil cloud in the region is R, r, θ, respectively satisfy the uniform distribution of (0, R), (0, π), (0, 2π). attitude azimuth angle θ c subject to a uniform distribution over [0, 2π], attitude tilt angle subject to a bimodal normal distribution, with the distribution equation shown below: where θ d and π - θ d is the distribution center of the attitude inclination angle, D is the standard deviation of the normal distribution, and ξ satisfies: The time-domain echo of the chaff cloud with different distributions is generated at different receiving angles.

3. The method according to claim 1, wherein, The processor executes the program to realize the steps of the method of any one of claims 1-3.

4. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The program is executed by the processor to realize the steps of the method of any one of claims 1-3.

5. A computer-readable storage medium having stored thereon a computer program, characterized in that, ​

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