阅读说明：本技术 箔条干扰模拟方法及箔条干扰模拟器 (Foil strip interference simulation method and foil strip interference simulator ) 是由 梁艳 杨红卫 王骁 于 2019-12-06 设计创作，主要内容包括：本发明涉及一种箔条干扰模拟方法及箔条干扰模拟器,属于雷达技术领域。本发明首先基于箔条电磁特性进行离线仿真,产生箔条干扰滤波器系数；之后在线产生具有箔条干扰特性的回波系数；进而产生箔条干扰模拟信号。利用本发明能够以较低的实现复杂度、较高的精度实现各种箔条干扰的模拟,包括舰载、机载和弹载等平台的箔条弹特性,各种风速、抛撒速度、抛撒方向,一次性抛洒、连续抛撒,各种频率范围,各种平台运动速度,适应各种雷达信号。本发明的高精度、低复杂度、通用性是传统箔条干扰模拟器所不具备的,具有极高的应用前景。(The invention relates to a foil strip interference simulation method and a foil strip interference simulator, and belongs to the technical field of radars. Firstly, performing off-line simulation based on electromagnetic characteristics of foil strips to generate foil strip interference filter coefficients; then, an echo coefficient with foil strip interference characteristics is generated on line; thereby generating a foil strip interference analog signal. The invention can realize the simulation of various foil interference with lower realization complexity and higher precision, including foil elasticity characteristics of ship-borne, airborne and missile-borne platforms, various wind speeds, throwing speeds and throwing directions, one-time throwing and continuous throwing, various frequency ranges and various platform movement speeds, and is suitable for various radar signals. The invention has high precision, low complexity and universality which are not possessed by the traditional foil strip interference simulator, and has extremely high application prospect.)

1. A foil strip disturbance simulation method, characterized in that the method comprises the steps of:

(1) performing off-line simulation based on the electromagnetic characteristics of the foil strips to generate foil strip interference filter coefficients;

(2) generating echo coefficients with foil interference characteristics by using the foil interference filter coefficients and the nonlinear conversion filter;

(3) and generating a foil strip interference analog signal by using the echo coefficient and the radar signal acquired in real time.

2. Foil strip interference simulation method according to claim 1, wherein the step (1) comprises the following steps:

(a) initializing simulation parameters, radar parameters, a foil strip bullet emitter, the environment of a foil strip bullet and foil strip bullet parameters;

(b) setting the simulation number of foil strips according to the Monte Carlo simulation times, and initializing the azimuth angle, the pitch angle, the position, the speed and the rotating speed of the nth foil strip according to the type of the foil strip launcher;

(c) determining a foil movement diffusion model according to the environment of the foil bullet;

(d) generating the position, the speed and the rotating speed of the kth time sampling of the ith foil in a life cycle by using the foil motion diffusion model, judging the life stage of the foil, wherein the generation stage comprises an immature stage, a mature stage and a fading stage, and selecting effective foils according to the life stage;

(e) generating an echo of the ith foil strip according to the polarization mode of the radar, the spatial position of the foil strip bullet and the scanning angle of the radar antenna;

(f) in the radar range, foil strips are divided according to range gates corresponding to the intermediate frequency sampling interval, and all foil strip echoes in the same range gate are coherently superposed to obtain the echo amplitude and phase of the mth range gate;

(g) counting survival stages of each foil strip cloud, and averaging echoes of all foil strip bombs to obtain an average survival stage;

(h) fitting the echo samples of each survival stage to obtain a probability density distribution function and a power spectrum of amplitude and phase characteristics of each survival stage;

(i) and respectively designing the nonlinear transformation filter of each survival stage according to the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage to generate corresponding foil strip interference filter coefficients.

3. The foil strip interference simulation method according to claim 2, wherein the step (c) comprises the steps of:

determining whether the environment of the foil strip bomb is dense atmosphere or sparse atmosphere,

if dense atmosphere, the step (c) comprises the steps of:

(c1-i) performing a force analysis on each foil strip in the dense atmosphere;

(c1-ii) obtaining a foil strip horizontal diffusion model according to the relation between the radius and the angular velocity of the inner circumference motion of the foil strip in the horizontal plane;

(c1-iii) calculating the change relation of the height of the foil strip along with the time according to an air viscosity coefficient formula;

(c1-iv) obtaining a foil strip descending speed formula, namely a vertical diffusion model, according to the change relation of the foil strip height along with time;

(c1-v) selecting a spherical uniform distribution or horizontal normal distribution model according to the type of the foil strip ejector, and initializing the azimuth angle and the pitch angle of the foil strip;

(c1-vi) initializing foil strip rotation speed;

if sparse atmosphere, the step (c) comprises the steps of:

(c2-i) establishing a motion equation of the translation of the foil strip;

(c2-ii) establishing an equation of motion for the rotation of the foil strip;

(c2-iii) initializing foil strip azimuth and pitch angles.

4. The foil strip interference simulation method according to claim 3, wherein the step of determining the survival stage of the foil strip is specifically:

if the minimum distance between the foil strips is not more than two times of the wavelength, the foil strips are in an immature stage;

when the cross section of the radar begins to decrease, the foil strip is in a fading period;

the minimum distance between the foil strips is more than two times of wavelength, and the cross section of the radar is not reduced, so that the foil strips are in the mature period.

5. The foil strip interference simulation method according to claim 4, wherein the selecting of the valid foil strips according to the survival stage in step (d) is specifically:

if the foil strips are in the immature stage, randomly determining the number of the effective foil strips according to the mutual effect and the influence of the adhesion factors on the number of the effective foil strips in the foil strip cloud; and if the film is in a mature period and a fading period, all the foil strips are taken as effective foil strips.

6. Foil strip disturbance simulation method according to claim 1,

the step (2) is specifically as follows: and generating an independent Gaussian random process by using the foil strip interference filter coefficient, and obtaining a related random sequence consistent with the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage through filtering and nonlinear transformation filter transformation to serve as the echo coefficient with the foil strip interference characteristic.

7. The foil strip interference simulation method according to claim 1, wherein the step (3) is specifically: and convolving the echo coefficient with the radar signal acquired in real time to generate a foil strip interference analog signal.

8. A foil strip interference simulator, comprising:

the foil strip electromagnetic characteristic off-line simulation unit is used for carrying out off-line simulation based on the electromagnetic characteristic of the foil strip to generate a foil strip interference filter coefficient;

the foil strip echo coefficient generator is used for generating an echo coefficient with foil strip interference characteristics by utilizing the foil strip interference filter coefficient and the nonlinear transformation filter;

the convolver is used for generating the foil strip interference analog signal by utilizing the echo coefficient and a radar signal acquired in real time;

and the signal transceiver is used for receiving the radar signal and transmitting the foil strip interference analog signal.

9. Foil strip interference simulator according to claim 8,

the foil strip electromagnetic characteristic off-line simulation unit comprises: the system comprises a main control subunit and an electromagnetic characteristic off-line simulation subunit;

the main control subunit comprises:

the radar parameter editing module is used for configuring radar parameters;

the foil strip interference simulation configuration module is used for configuring the foil strip ejector, the environment where the foil strip ejector is located and the parameters of the foil strip ejector;

the microwave/frequency storage control module is used for configuring simulation parameters;

the electromagnetic characteristic off-line simulation subunit comprises:

the foil strip bullet motion characteristic modeling module is used for setting the simulation number of foil strip bullets according to the Monte Carlo simulation times and initializing the foil strip azimuth angle, the pitch angle, the position, the speed and the rotating speed of the nth foil strip bullet according to the type of the foil strip bullet emitter; determining a foil movement diffusion model according to the environment of the foil bullet;

the foil impulse response process simulation module is used for generating the position, the speed and the rotating speed of the kth time sample of the ith foil in a life cycle by utilizing the foil motion diffusion model, judging the life stage of the foil, wherein the generation stage comprises an immature stage, a mature stage and a fading stage, and selecting effective foils according to the life stage; generating an echo of the ith foil strip according to the polarization mode of the radar, the spatial position of the foil strip bullet and the scanning angle of the radar antenna;

the foil strip statistical characteristic generation module is used for dividing foil strips according to the range gates corresponding to the intermediate frequency sampling intervals in the radar range and coherently superposing all foil strip echoes in the same range gate to obtain the echo amplitude and phase of the mth range gate; counting survival stages of each foil strip cloud, and averaging echoes of all foil strip bombs to obtain an average survival stage; fitting the echo samples of each survival stage to obtain a probability density distribution function and a power spectrum of amplitude and phase characteristics of each survival stage;

and the nonlinear filter design module is used for respectively designing the nonlinear transformation filter of each survival stage according to the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage to generate corresponding foil strip interference filter coefficients.

10. The foil interference simulator of claim 8, wherein said foil echo coefficient generator comprises:

the independent Gaussian random sequence generating unit is used for generating an independent Gaussian random process;

and the nonlinear transformation filter is generated by utilizing the foil interference filter coefficient generated by the foil electromagnetic characteristic off-line simulation unit and is used for filtering the independent Gaussian random process to obtain an echo coefficient with the foil interference characteristic.

11. The foil strip interference simulator of claim 8, wherein said convolver comprises:

a convolution operation unit, a time delay unit, an up-conversion unit and a DAC playing unit which are connected in sequence,

the convolution operation unit is used for acquiring the echo coefficient with the foil strip interference characteristic from the foil strip echo coefficient generator and acquiring the radar signal from the signal transceiver; convolving the echo coefficient with the radar signal to generate the foil strip interference analog signal;

the foil strip interference analog signal is sent to the signal transceiver through the delay unit, the up-conversion unit and the DAC playing unit.

Technical Field

The invention relates to the technical field of radar, in particular to the technical field of foil strip interference simulation, and specifically relates to a foil strip interference simulation method and a foil strip interference simulator.

Background

The foil strip interference means that a foil strip is thrown in the air to reflect radar signals, the signals are used as false targets to interfere early warning and detection radars of enemies in interference modes such as dilution and mass centers, or the signals are used as tracking radars for luring baits to bias the enemies, or interference corridors with certain length, width and thickness are formed and used for shielding own targets. As the earliest and most widely used passive interference measures, foil strip interference has become a common interference capability for the battle objects such as airplanes, missiles, ships and the like.

The foil strip interference characteristics are mainly dependent on the motion dispersion characteristics of the foil strip and the echo characteristics of the radar reflection. The motion characteristic of the device is related to the foil throwing speed and the throwing direction of the foil releasing platform, the wind power, the air density and the viscosity of the environment where the foil is located, and is one of the main factors influencing the radar echo characteristic of the foil. The echo characteristics of the radar are related to the working system and the working waveform of the radar.

Foil strip interference simulators are widely used in performance testing and testing of various equipment that is resistant to foil strip interference. In the prior art, as shown in fig. 1, a foil interference simulator receives radar signals through an antenna and a receiving unit (the receiving unit includes an amplifier, a filter, a microwave component such as a frequency converter, and an a/D analog-to-digital converter, etc.), a foil echo modulation coefficient generator generates foil echo modulation coefficients according to various characteristics (including amplitude characteristics, phase characteristics, power spectrum characteristics, etc.) of a foil, and convolves the foil echo modulation coefficients with the received radar signals, and finally sends the modulated signals to radar equipment through a transmitting unit (including a microwave component such as a D/a digital-to-analog converter, a frequency converter, a filter, a power amplifier, etc.), so as to simulate real foil interference.

The existing foil strip interference simulation method is mainly an empirical formula method. Establishing a statistical formula (typical formula is Rayleigh distribution amplitude, uniformly distributed phase and Gaussian distribution power spectrum) according to measured data of the foil strip interference, establishing a foil strip echo modulation coefficient table, selecting a modulation coefficient through a table look-up method, and performing convolution with a received radar signal, so that the amplitude, the phase and the power spectrum of the generated interference signal are always consistent with the statistical formula. The modulation factor is usually kept constant during the simulation. The empirical formula method is simple to implement, but the universality and the precision are poor, mainly because the motion diffusion characteristic and the radar echo characteristic factors influencing the foil strip interference are numerous, and the actually measured data in one scene is not suitable for other scenes.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a foil strip interference simulation method and a foil strip interference simulator which realize accurate simulation with lower complexity and greatly improve the precision and the applicability.

In order to achieve the above object, the foil strip interference simulation method of the present invention comprises the steps of:

(1) performing off-line simulation based on the electromagnetic characteristics of the foil strips to generate foil strip interference filter coefficients;

(2) generating echo coefficients with foil interference characteristics by using the foil interference filter coefficients and the nonlinear conversion filter;

(3) and generating a foil strip interference analog signal by using the echo coefficient and the radar signal acquired in real time.

In the foil strip interference simulation method, the step (1) specifically comprises the following steps:

(a) initializing simulation parameters, radar parameters, a foil strip bullet emitter, the environment of a foil strip bullet and foil strip bullet parameters;

(b) setting the simulation number of foil strips according to the Monte Carlo simulation times, and initializing the azimuth angle, the pitch angle, the position, the speed and the rotating speed of the nth foil strip according to the type of the foil strip launcher;

(c) determining a foil movement diffusion model according to the environment of the foil bullet;

(d) generating the position, the speed and the rotating speed of the kth time sampling of the ith foil in a life cycle by using the foil motion diffusion model, judging the life stage of the foil, wherein the generation stage comprises an immature stage, a mature stage and a fading stage, and selecting effective foils according to the life stage;

(e) generating an echo of the ith foil strip according to the polarization mode of the radar, the spatial position of the foil strip bullet and the scanning angle of the radar antenna;

(f) in the radar range, foil strips are divided according to range gates corresponding to the intermediate frequency sampling interval, and all foil strip echoes in the same range gate are coherently superposed to obtain the echo amplitude and phase of the mth range gate;

(g) counting survival stages of each foil strip cloud, and averaging echoes of all foil strip bombs to obtain an average survival stage;

(h) fitting the echo samples of each survival stage to obtain a probability density distribution function and a power spectrum of amplitude and phase characteristics of each survival stage;

(i) and respectively designing the nonlinear transformation filter of each survival stage according to the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage to generate corresponding foil strip interference filter coefficients.

In the foil strip interference simulation method, the step (c) specifically comprises the following steps:

determining whether the environment of the foil strip bomb is dense atmosphere or sparse atmosphere,

if dense atmosphere, the step (c) comprises the steps of:

(c1-i) performing a force analysis on each foil strip in the dense atmosphere;

(c1-ii) obtaining a foil strip horizontal diffusion model according to the relation between the radius and the angular velocity of the inner circumference motion of the foil strip in the horizontal plane;

(c1-iii) calculating the change relation of the height of the foil strip along with the time according to an air viscosity coefficient formula;

(c1-iv) obtaining a foil strip descending speed formula, namely a vertical diffusion model, according to the change relation of the foil strip height along with time;

(c1-v) selecting a spherical uniform distribution or horizontal normal distribution model according to the type of the foil strip ejector, and initializing the azimuth angle and the pitch angle of the foil strip;

(c1-vi) initializing foil strip rotation speed;

if sparse atmosphere, the step (c) comprises the steps of:

(c2-i) establishing a motion equation of the translation of the foil strip;

(c2-ii) establishing an equation of motion for the rotation of the foil strip;

(c2-iii) initializing foil strip azimuth and pitch angles.

In the foil strip interference simulation method, the step of judging the survival stage of the foil strip is specifically as follows:

if the minimum distance between the foil strips is not more than two times of the wavelength, the foil strips are in an immature stage;

when the cross section of the radar begins to decrease, the foil strip is in a fading period;

the minimum distance between the foil strips is more than two times of wavelength, and the cross section of the radar is not reduced, so that the foil strips are in the mature period.

In the foil strip interference simulation method, the selecting of the effective foil strips according to the survival stage in the step (d) specifically comprises the following steps:

if the foil strips are in the immature stage, randomly determining the number of the effective foil strips according to the mutual effect and the influence of the adhesion factors on the number of the effective foil strips in the foil strip cloud; and if the film is in a mature period and a fading period, all the foil strips are taken as effective foil strips.

In the foil strip interference simulation method, the step (2) is specifically as follows: and generating an independent Gaussian random process by using the foil strip interference filter coefficient, and obtaining a related random sequence consistent with the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage through filtering and nonlinear transformation filter transformation to serve as the echo coefficient with the foil strip interference characteristic.

In the foil strip interference simulation method, the step (3) is specifically as follows: and convolving the echo coefficient with the radar signal acquired in real time to generate a foil strip interference analog signal.

The invention also provides a foil strip interference simulator comprising:

the foil strip electromagnetic characteristic off-line simulation unit is used for carrying out off-line simulation based on the electromagnetic characteristic of the foil strip to generate a foil strip interference filter coefficient;

the foil strip echo coefficient generator is used for generating an echo coefficient with foil strip interference characteristics by utilizing the foil strip interference filter coefficient and the nonlinear transformation filter;

the convolver is used for generating the foil strip interference analog signal by utilizing the echo coefficient and a radar signal acquired in real time;

and the signal transceiver is used for receiving the radar signal and transmitting the foil strip interference analog signal.

In the foil strip interference simulator, the foil strip electromagnetic characteristic off-line simulation unit comprises: the system comprises a main control subunit and an electromagnetic characteristic off-line simulation subunit;

the main control subunit comprises:

the radar parameter editing module is used for configuring radar parameters;

the foil strip interference simulation configuration module is used for configuring the foil strip ejector, the environment where the foil strip ejector is located and the parameters of the foil strip ejector;

the microwave/frequency storage control module is used for configuring simulation parameters;

the electromagnetic characteristic off-line simulation subunit comprises:

the foil strip bullet motion characteristic modeling module is used for setting the simulation number of foil strip bullets according to the Monte Carlo simulation times and initializing the foil strip azimuth angle, the pitch angle, the position, the speed and the rotating speed of the nth foil strip bullet according to the type of the foil strip bullet emitter; determining a foil movement diffusion model according to the environment of the foil bullet;

the foil impulse response process simulation module is used for generating the position, the speed and the rotating speed of the kth time sample of the ith foil in a life cycle by utilizing the foil motion diffusion model, judging the life stage of the foil, wherein the generation stage comprises an immature stage, a mature stage and a fading stage, and selecting effective foils according to the life stage; generating an echo of the ith foil strip according to the polarization mode of the radar, the spatial position of the foil strip bullet and the scanning angle of the radar antenna;

the foil strip statistical characteristic generation module is used for dividing foil strips according to the range gates corresponding to the intermediate frequency sampling intervals in the radar range and coherently superposing all foil strip echoes in the same range gate to obtain the echo amplitude and phase of the mth range gate; counting survival stages of each foil strip cloud, and averaging echoes of all foil strip bombs to obtain an average survival stage; fitting the echo samples of each survival stage to obtain a probability density distribution function and a power spectrum of amplitude and phase characteristics of each survival stage;

and the nonlinear filter design module is used for respectively designing the nonlinear transformation filter of each survival stage according to the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage to generate corresponding foil strip interference filter coefficients.

In the foil strip interference simulator, the foil strip echo coefficient generator comprises:

the independent Gaussian random sequence generating unit is used for generating an independent Gaussian random process;

and the nonlinear transformation filter is generated by utilizing the foil interference filter coefficient generated by the foil electromagnetic characteristic off-line simulation unit and is used for filtering the independent Gaussian random process to obtain an echo coefficient with the foil interference characteristic.

In the foil strip interference simulator, the convolver comprises:

a convolution operation unit, a time delay unit, an up-conversion unit and a DAC playing unit which are connected in sequence,

the convolution operation unit is used for acquiring the echo coefficient with the foil strip interference characteristic from the foil strip echo coefficient generator and acquiring the radar signal from the signal transceiver; convolving the echo coefficient with the radar signal to generate the foil strip interference analog signal;

the foil strip interference analog signal is sent to the signal transceiver through the delay unit, the up-conversion unit and the DAC playing unit.

By adopting the foil strip interference simulation method and the foil strip interference simulator, offline simulation is performed on the basis of electromagnetic characteristics of foil strips to generate foil strip interference filter coefficients; then, an echo coefficient with foil strip interference characteristics is generated on line; thereby generating a foil strip interference analog signal. The invention can realize the simulation of various foil interference with lower realization complexity and higher precision, including foil elasticity characteristics of ship-borne, airborne and missile-borne platforms, various wind speeds, throwing speeds and throwing directions, one-time throwing and continuous throwing, various frequency ranges and various platform movement speeds, and is suitable for various radar signals. The invention has high precision, low complexity and universality which are not possessed by the traditional foil strip interference simulator, and has extremely high application prospect.

Drawings

Fig. 1 is a schematic diagram of a prior art foil strip interference simulator.

Fig. 2 is a schematic diagram of the structure of a foil strip interference simulator of the present invention.

Fig. 3 is a flow chart of the steps of the foil strip interference simulation method of the present invention.

Fig. 4 is a schematic diagram of an implementation manner of an off-line simulation module for electromagnetic characteristics of a foil strip in the foil strip interference simulator according to the present invention.

Fig. 5 is a schematic diagram of an implementation manner of an echo coefficient online generator of a foil strip in the foil strip interference simulator of the present invention.

FIG. 6 is a schematic diagram of a phase distribution for evaluating interference effects using the foil strip interference simulator of the present invention.

FIG. 7 is a schematic power spectrum distribution diagram for evaluating interference effects using the foil strip interference simulator of the present invention.

Fig. 8 is a schematic diagram of a process of designing a foil strip bullet in the foil strip interference simulation method of the present invention.

Fig. 9 is a schematic flow chart of a foil strip interference simulator in a real application mode according to the present invention.

Detailed Description

In order to clearly understand the technical contents of the present invention, the following examples are given in detail.

Fig. 2 is a schematic structural diagram of a foil strip interference simulator according to the present invention.

In one embodiment, the foil strip interference simulator, as shown in fig. 2, comprises:

the foil strip electromagnetic characteristic off-line simulation unit is used for carrying out off-line simulation based on the electromagnetic characteristic of the foil strip to generate a foil strip interference filter coefficient;

the foil strip echo coefficient generator is used for generating an echo coefficient with foil strip interference characteristics by utilizing the foil strip interference filter coefficient and the nonlinear transformation filter;

the convolver is used for generating the foil strip interference analog signal by utilizing the echo coefficient and a radar signal acquired in real time;

and the signal transceiver is used for receiving the radar signal and transmitting the foil strip interference analog signal.

Accordingly, a foil strip interference simulation method implemented by the foil strip interference simulator of the embodiment, as shown in fig. 3, includes the following steps:

(1) performing off-line simulation based on the electromagnetic characteristics of the foil strips to generate foil strip interference filter coefficients;

(2) generating echo coefficients with foil interference characteristics by using the foil interference filter coefficients and the nonlinear conversion filter;

(3) and generating a foil strip interference analog signal by using the echo coefficient and the radar signal acquired in real time.

In a preferred embodiment, the off-line simulation unit for electromagnetic properties of a foil strip in the foil strip interference simulator comprises: the device comprises a main control subunit and an electromagnetic characteristic off-line simulation subunit.

Wherein, the main control subunit includes:

the radar parameter editing module is used for configuring radar parameters;

the foil strip interference simulation configuration module is used for configuring the foil strip ejector, the environment where the foil strip ejector is located and the parameters of the foil strip ejector;

and the microwave/frequency storage control module is used for configuring simulation parameters.

Wherein, the electromagnetic characteristic off-line simulation subunit comprises:

the foil strip bullet motion characteristic modeling module is used for setting the simulation number of foil strip bullets according to the Monte Carlo simulation times and initializing the foil strip azimuth angle, the pitch angle, the position, the speed and the rotating speed of the nth foil strip bullet according to the type of the foil strip bullet emitter; determining a foil movement diffusion model according to the environment of the foil bullet;

the foil impulse response process simulation module is used for generating the position, the speed and the rotating speed of the kth time sample of the ith foil in a life cycle by utilizing the foil motion diffusion model, judging the life stage of the foil, wherein the generation stage comprises an immature stage, a mature stage and a fading stage, and selecting effective foils according to the life stage; generating an echo of the ith foil strip according to the polarization mode of the radar, the spatial position of the foil strip bullet and the scanning angle of the radar antenna;

the foil strip statistical characteristic generation module is used for dividing foil strips according to the range gates corresponding to the intermediate frequency sampling intervals in the radar range and coherently superposing all foil strip echoes in the same range gate to obtain the echo amplitude and phase of the mth range gate; counting survival stages of each foil strip cloud, and averaging echoes of all foil strip bombs to obtain an average survival stage; fitting the echo samples of each survival stage to obtain a probability density distribution function and a power spectrum of amplitude and phase characteristics of each survival stage;

and the nonlinear filter design module is used for respectively designing the nonlinear transformation filter of each survival stage according to the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage to generate corresponding foil strip interference filter coefficients.

Accordingly, in the foil interference simulation method implemented by using the foil interference simulator of this embodiment, the step (1) specifically includes the following steps:

(a) initializing simulation parameters, radar parameters, a foil strip bullet emitter, the environment of a foil strip bullet and foil strip bullet parameters;

(b) setting the simulation number of foil strips according to the Monte Carlo simulation times, and initializing the azimuth angle, the pitch angle, the position, the speed and the rotating speed of the nth foil strip according to the type of the foil strip launcher;

(c) determining a foil movement diffusion model according to the environment of the foil bullet;

(d) generating the position, the speed and the rotating speed of the kth time sampling of the ith foil in a life cycle by using the foil motion diffusion model, judging the life stage of the foil, wherein the generation stage comprises an immature stage, a mature stage and a fading stage, and selecting effective foils according to the life stage;

(e) generating an echo of the ith foil strip according to the polarization mode of the radar, the spatial position of the foil strip bullet and the scanning angle of the radar antenna;

(f) in the radar range, foil strips are divided according to range gates corresponding to the intermediate frequency sampling interval, and all foil strip echoes in the same range gate are coherently superposed to obtain the echo amplitude and phase of the mth range gate;

(g) counting survival stages of each foil strip cloud, and averaging echoes of all foil strip bombs to obtain an average survival stage;

(h) fitting the echo samples of each survival stage to obtain a probability density distribution function and a power spectrum of amplitude and phase characteristics of each survival stage;

(i) and respectively designing the nonlinear transformation filter of each survival stage according to the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage to generate corresponding foil strip interference filter coefficients.

Wherein, the step (c) specifically comprises the following steps:

determining whether the environment of the foil strip bomb is dense atmosphere or sparse atmosphere,

if dense atmosphere, the step (c) comprises the steps of:

(c1-i) performing a force analysis on each foil strip in the dense atmosphere;

(c1-ii) obtaining a foil strip horizontal diffusion model according to the relation between the radius and the angular velocity of the inner circumference motion of the foil strip in the horizontal plane;

(c1-iii) calculating the change relation of the height of the foil strip along with the time according to an air viscosity coefficient formula;

(c1-iv) obtaining a foil strip descending speed formula, namely a vertical diffusion model, according to the change relation of the foil strip height along with time;

(c1-v) selecting a spherical uniform distribution or horizontal normal distribution model according to the type of the foil strip ejector, and initializing the azimuth angle and the pitch angle of the foil strip;

(c1-vi) initializing foil strip rotation speed;

if sparse atmosphere, the step (c) comprises the steps of:

(c2-i) establishing a motion equation of the translation of the foil strip;

(c2-ii) establishing an equation of motion for the rotation of the foil strip;

(c2-iii) initializing foil strip azimuth and pitch angles.

The step of judging the survival stage of the foil strip is specifically as follows:

if the minimum distance between the foil strips is not more than two times of the wavelength, the foil strips are in an immature stage;

when the cross section of the radar begins to decrease, the foil strip is in a fading period;

the minimum distance between the foil strips is more than two times of wavelength, and the cross section of the radar is not reduced, so that the foil strips are in the mature period.

Selecting effective foil strips according to the survival stage in the step (d), wherein the selection specifically comprises the following steps:

if the foil strips are in the immature stage, randomly determining the number of the effective foil strips according to the mutual effect and the influence of the adhesion factors on the number of the effective foil strips in the foil strip cloud; and if the film is in a mature period and a fading period, all the foil strips are taken as effective foil strips.

In another preferred embodiment, the foil strip echo coefficient generator in the foil strip interference simulator comprises:

the independent Gaussian random sequence generating unit is used for generating an independent Gaussian random process;

and the nonlinear transformation filter is generated by utilizing the foil interference filter coefficient generated by the foil electromagnetic characteristic off-line simulation unit and is used for filtering the independent Gaussian random process to obtain an echo coefficient with the foil interference characteristic.

Correspondingly, the step (2) is specifically as follows: and generating an independent Gaussian random process by using the foil strip interference filter coefficient, and obtaining a related random sequence consistent with the probability density distribution function and the power spectrum of the amplitude and phase characteristics of each survival stage through filtering and nonlinear transformation filter transformation to serve as the echo coefficient with the foil strip interference characteristic.

In a more preferred embodiment, the convolver of the foil strip interference simulator comprises:

a convolution operation unit, a time delay unit, an up-conversion unit and a DAC playing unit which are connected in sequence,

the convolution operation unit is used for acquiring the echo coefficient with the foil strip interference characteristic from the foil strip echo coefficient generator and acquiring the radar signal from the signal transceiver; convolving the echo coefficient with the radar signal to generate the foil strip interference analog signal;

the foil strip interference analog signal is sent to the signal transceiver through the delay unit, the up-conversion unit and the DAC playing unit.

Correspondingly, the step (3) is specifically as follows: and convolving the echo coefficient with the radar signal acquired in real time to generate a foil strip interference analog signal.

In practical application, the invention aims to realize an off-line simulation and on-line interference generation foil strip interference simulation method. The method comprises the steps of simulating foil interference by adopting a statistical method, simulating a foil diffusion process by utilizing a fluid mechanics principle, simulating echo characteristics of the foil to a radar by utilizing an electromagnetic principle, establishing a statistical model of scattering amplitude-phase characteristics and power spectral density by utilizing a Monte Carlo simulation method, generating a foil interference signal by utilizing a zero-memory nonlinear transformation method, and realizing accurate simulation of the foil interference signal with lower complexity, so that the precision and the applicability of a foil simulator are remarkably improved.

Fig. 2 presents a schematic view of the principle of the foil strip interference simulator of the invention. Compared with the traditional foil strip simulator, the invention adds two modules. One is a foil strip electromagnetic characteristic off-line simulation module, and the other is a foil strip echo coefficient on-line generator.

An implementation of the foil strip electromagnetic characteristic off-line simulation module is shown in fig. 4. The method mainly comprises radar parameter editing, foil strip interference simulation configuration, microwave/frequency storage control, foil strip elastic motion characteristic modeling, foil strip impulse response process simulation, foil strip statistical characteristic generation and nonlinear filter design. The main working process is as follows: the main control software configures radar parameters, foil strip interference application scenes and parameters; foil strip bullet electromagnetic characteristic simulation software carries out mechanical modeling and motion diffusion model modeling of foil strips according to configured radar parameters and foil strip interference scene parameters, simulates radar scattering echoes of the foil strip bullets according to an impulse response principle, obtains statistical characteristics of the foil strip scattering characteristics (including probability distribution and parameters of immature stages, mature stages, amplitudes and phases, power spectral density and the like of foil strip clouds), and designs a nonlinear filter, so that a random process generated after an independent Gaussian random process is subjected to nonlinear transformation is consistent with the amplitude, the phase and the power spectral density of the foil strip clouds.

An online generator implementation of foil strip echo coefficients is shown in fig. 5. The method comprises independent Gaussian random sequence generation, nonlinear transformation filtering, radar signal acquisition, a convolution operation unit, a delay unit, an up-conversion unit and a DAC playing unit, and finally foil strip interference analog signals are generated on line. The main working process is as follows: and generating a nonlinear transformation filter according to the foil interference filter coefficient input by the foil electromagnetic characteristic off-line simulation software, and filtering the Gaussian process generated by the independent Gaussian random sequence generation module to obtain the convolution coefficient of the foil interference characteristic. And the convolution operation unit is used for realizing the convolution with the radar signal of the radar signal acquisition unit and realizing the simulation of the foil strip interference signal. And finally, transmitting the generated foil strip interference analog signal through time delay, up-conversion and digital-to-analog conversion.

Corresponding to the simulator structure, the method for realizing the foil strip interference simulation of the invention separates two parts, namely line simulation and on-line interference generation.

The off-line simulation stage mainly comprises:

1. initializing system parameters such as radar and foil strip bomb situation information and foil strip bomb immature stage/mature stage time, wind speed, platform speed, frequency, polarization, foil strip size, number and the like;

2. generating a random distribution of the foil strips in the life cycle of a plurality of foil strip bullets by using a Monte Carlo method under the same configuration;

3. dividing foil strips in each foil strip bullet into foil strips at a distance gate corresponding to an intermediate frequency sampling interval, and performing coherent superposition on the foil strip echoes in the same distance gate to generate a plurality of echo samples;

4. counting the probability distribution function and the power spectral density function of the amplitude and the phase of all echo samples based on all the echo samples;

5. and designing a nonlinear transformation filter according to the amplitude, the phase and the power spectrum of the input echo, and downloading the filter coefficient to a simulator host.

The online interference generation stage mainly comprises:

1. configuring a digital filter according to the input filter coefficient, filtering the Gaussian random sequence to generate different echo coefficients according to the immature period and the mature period, and then convolving the echo coefficients with the radar signal in real time;

2. and transmitting a simulated foil strip rebound wave signal to finish the generation of foil strip interference.

In order to evaluate the simulation performance of the disturbance characteristic of the invention, the influence of two wind speeds of 50m/s on the generated disturbance is evaluated by the invention, and the result is shown in a phase distribution of fig. 6 and a power spectrum distribution diagram of fig. 7, and the result has high consistency with a theoretical result. The 60Hz spectrum broadening of FIG. 6 is mainly due to the maximum 200Hz Doppler shift caused by wind speed and the projection of the horizontal and vertical movement of the foil strip and the movement of the foil strip itself in the radial direction.

In practical application, the implementation process of the invention is as follows:

1. the foil strip bullet is designed according to requirements, and the specific process is shown in fig. 8.

2. And (5) performing off-line simulation.

a) The simulation parameters, radar parameters, foil projectile launcher, environment in which the foil projectile is located, and foil projectile parameters are initialized as per the following table. The parameter of the interference simulation type can be configured to be corrected, and at the moment, the impact response of a single foil strip bomb in a set simulation time length is output by the upper computer and is mainly used for correcting the performance of the radar; the statistical evaluation of the radar performance can only configure the parameter as a performance analysis mode, at the moment, the upper computer outputs a nonlinear filter coefficient of foil strip interference, and the generated channel response has statistical significance.

TABLE 1 foil strip interference simulation initialization parameter setting table

b) And setting the simulation number of the foil strips according to the Monte Carlo simulation times, and initializing the azimuth angle, the pitch angle, the position, the speed and the rotating speed of the nth foil strip according to the type of the foil strip launcher.

c) And judging whether the environment of the platform is dense atmosphere or sparse atmosphere.

(1) If dense atmosphere:

i. completing the stress analysis of each foil strip in the dense atmosphere;

ii, obtaining a foil horizontal diffusion model according to the relation between the radius and the angular velocity of the inner circumference motion of the foil in the horizontal plane and the motion relation of the foil in the horizontal plane;

calculating the change of the height of the foil strip along with the time according to an air viscosity coefficient formula;

obtaining a foil strip descending speed formula, namely a vertical diffusion model;

v, selecting models of spherical surface uniform distribution, horizontal normal distribution and the like according to the type of the foil strip ejector, and initializing the azimuth angle and the pitch angle of the foil strip;

initializing foil strip rotation speed.

(2) If the atmosphere is sparse:

i. establishing a motion equation of the translation of the foil strip;

establishing a motion equation of foil strip rotation;

initializing foil strip azimuth and pitch angles.

d) Generating the position, the speed and the rotating speed of the kth time sampling of the ith foil strip in the life cycle by utilizing a motion diffusion model; and (4) judging whether the k time is in an immature stage (the judgment criterion is mainly whether the minimum distance between the foil strips is more than two wavelengths). If the film is in the immature stage, the influence of other factors such as the mutual coupling effect and adhesion on the effective foil number of the foil cloud is followedThe number of active foil strips is determined by machine, i.e. randomly selected as η during the immature period₁η₂η₃η₄The foil strips are used as effective foil strips; all foil strips served as valid foil strips during the maturation and decay periods.

e) And generating an echo of the ith foil strip according to system parameters such as the polarization mode of the radar, the spatial position of the foil strip bullet, the scanning angle of the radar antenna and the like.

f) In the radar range, foil strips are divided according to the range gates corresponding to the intermediate frequency sampling interval, and all foil strip echoes in the same range gate are coherently superposed to obtain the echo amplitude and phase of the mth range gate.

g) And counting the immature period, the mature period and the fading period of each foil strip cloud, and averaging the echoes of all the foil strip bombs to obtain the average immature period, mature period and fading period. The judgment of the immature period is based on the condition that the distance between the minimum foil strips is less than two times of the wavelength or the radar cross section is not maximized; the fading period is determined by the beginning of the decrease in the cross-sectional area of the radar.

h) And fitting the echo samples in the immature period, the mature period and the fading period to obtain a probability density distribution function and a power spectrum of the amplitude and phase characteristics in each period.

i) And respectively designing a nonlinear transformation filter according to the immature period, the mature period and the fading period, so that random independent Gaussian random processes generate random sequences which are the same as the statistical characteristics and the power spectral density function after being filtered, and outputting the filter coefficients to a frequency storage module.

3. Online interference generation

And then, generating a radar echo of the foil cloud on line through a frequency storage module:

a) and generating an independent Gaussian random process, and obtaining a related random sequence consistent with the statistical characteristics of the amplitude, the phase and the power spectrum through filtering and nonlinear transformation to serve as the foil cloud echo characteristic.

b) And (4) convolving the foil cloud echo characteristics with the radar echo to realize the modeling of the foil cloud echo.

The implementation is shown in fig. 9.

The simulator can realize the simulation of various foil strip interferences with lower complexity and universal software and hardware architecture and higher precision, and comprises foil strip elastic characteristics of platforms such as ship-borne, airborne and missile-borne platforms, various wind speeds, scattering speeds and scattering directions, one-time scattering and continuous scattering, various frequency ranges and various platform motion speeds, and is suitable for various radar signals.

By adopting the foil strip interference simulation method and the foil strip interference simulator, offline simulation is performed on the basis of electromagnetic characteristics of foil strips to generate foil strip interference filter coefficients; then, an echo coefficient with foil strip interference characteristics is generated on line; thereby generating a foil strip interference analog signal. The invention can realize the simulation of various foil interference with lower realization complexity and higher precision, including foil elasticity characteristics of ship-borne, airborne and missile-borne platforms, various wind speeds, throwing speeds and throwing directions, one-time throwing and continuous throwing, various frequency ranges and various platform movement speeds, and is suitable for various radar signals. The invention has high precision, low complexity and universality which are not possessed by the traditional foil strip interference simulator, and has extremely high application prospect.

In this specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.