CN107917646B - An anti-jamming guidance method for infrared air-to-air missiles based on target terminal reachable area prediction - Google Patents

Abstract

The anti-jamming guidance method for infrared air-to-air missiles based on the prediction of the future position of the target, the steps are as follows: (1) The infrared air-to-air missile seeker obtains the measurement information of the target, and filters and estimates the target state information to estimate the remaining flight time of the missile; (2) Assuming that the target acceleration obeys the probability distribution of the gamma distribution, calculate the position distribution of the target at the next moment and the moment of encounter; (3) Calculate the possible position of the missile at the next moment, and calculate the position at the next moment with the maximum flight ability at the moment of encounter. (4) By comparing the coverage area of the missile with the reachable area of the target, calculate the position at the next moment corresponding to the area covered by the missile with the greatest probability; (5) Calculate the control command of the missile according to the position at the next moment ; (6) Apply control to the missile and return to step (1) until the missile meets the target.

Description

An anti-jamming guidance of infrared air-to-air missile based on target terminal reachable area prediction method

technical field

The invention relates to an anti-jamming guidance algorithm of an infrared air-to-air missile under the condition of target dropping interference, especially an anti-jamming guidance algorithm under the condition that true and false targets cannot be distinguished.

Background technique

After the target aircraft is threatened by the missile attack, in order to improve the survival rate of the aircraft, the jamming bombs similar to the spectral characteristics of the aircraft are released. In order to accurately hit the target, the infrared air-to-air missile needs to use hardware and algorithms for anti-jamming, and finally hit the target accurately.

The paper "Anti-jamming Analysis of Infrared Imaging Guidance" by Jia Qiurui et al. and "Anti-jamming Technology of Infrared Imaging Seeker" by Li Lijuan et al. both introduce in detail how the infrared seeker can resist interference by dropping jamming bombs on the target aircraft. Analyze the differences in characteristics such as spectrum, motion, grayscale and spatial distribution to identify targets and interference. Arthur Vermeulen studied the guidance method of infrared air-to-air missiles in the case of interference in the paper "Missile avoidance manoeuvres with simultaneous decoy deployment", analyzing The relationship between the miss-target amount of this guidance method of tracking the energy center in different combat environments is analyzed. D.Dionne studied the guidance method based on predictive control in the case of a single jammer in the paper "Predictive Guidance for Pursuit-EvasionEngagements Involving Decoys". However, with the development of infrared jamming bombs, its spectral characteristics and motion characteristics are more and more similar to those of aircraft, and the interference has been greatly improved in terms of shape and motion, especially when the infrared imaging seeker is far away and the accuracy is not high. , There is a certain difficulty and error rate in identifying the target aircraft and jamming missiles through the infrared air-to-air missile seeker. In order to improve the anti-jamming capability of the infrared air-to-air missile and prevent the missile from being deceived by the jamming missile, the guidance algorithm of the infrared air-to-air missile needs to be improved. .

In order to improve the success rate of the missile intercepting the target when the target cannot be accurately identified, the present invention proposes a guidance method based on predictive guidance. The guidance method is based on the prediction of the target and the future reachable area of the jamming missile, combined with the range of the missile's own capabilities, and uses the maximum probability to cover the undistinguishable true and false target area as an indicator to calculate the guidance command, so as to achieve the unrecognizable target. Accurately hit the target while distinguishing the target.

SUMMARY OF THE INVENTION

The technical solution of the present invention is to provide an anti-jamming guidance method for infrared air-to-air missiles, so as to improve the hit rate of the infrared air-to-air missiles after they are interfered with the target.

The technical solution of the present invention is: an anti-jamming guidance method for infrared air-to-air missiles based on prediction guidance, the steps are as follows:

(1) The infrared air-to-air missile seeker obtains the measurement information of the target, and filters and estimates the target state information to estimate the remaining flight time of the missile;

(2) Assuming that the target acceleration obeys the probability distribution of the gamma distribution, calculate the position distribution area of the target at the next moment and the encounter moment;

(3) Calculate the reachable area of the missile at the next moment, and calculate the area that the missile can reach at the final moment t _f with the maximum flight capability at each possible position at the next moment;

(4) It is proposed that the missile's maximum probability of hitting the target is the performance index, and the missile control command is calculated by maximizing the performance;

(6) Control the missile and return to step (1) to loop until the missile meets the target.

The advantages of the present invention compared with the prior art are:

(1) the present invention compared with traditional anti-jamming can be used in the end section of interference identification, can supplement the guidance problem that infrared air-to-air missiles cannot identify true and false targets according to other features;

(2) The use of this method can make up for the deficiencies of the seeker hardware to a certain extent, for example, the target and interference cannot be identified due to low resolution;

(3) Compared with the general anti-jamming guidance methods such as tracking the target and jamming the center of mass, it has a higher accuracy rate and can improve the hit rate of the missile.

Description of drawings

Figure 1 is the guidance flow chart of the anti-jamming guidance of the infrared air-to-air missile;

Figure 2 is a two-dimensional plane engagement model of the missile and the target;

Figure 3 is a schematic diagram of the acceleration probability distribution of the target;

Figure 4 is a schematic diagram of the missile reachable area and the area where the target may appear;

Figure 5 is a schematic diagram of the ballistic trajectory of the projectile when t _go = 4.5s when the target drops the jamming projectile

Figure 6 is a comparison of the amount of misses when the target drops jamming bombs at different times and the amount of missile misses under different guidance laws.

Figure 7 is a schematic diagram of the ballistic trajectory of the projectile when t _go = 2s when the target throws the jamming projectile

Figure 8 is a comparison of the amount of misses between the remaining flight time t _go and the amount of missile misses under different guidance laws after the target drops the jamming bomb.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

The implementation steps of the present invention are as follows:

1. First establish the engagement model in Figure 2

Taking the two-dimensional plane pursuit model as the research object, the state quantity is selected as x(t)=[r _x (t) r _y (t) v _x (t) v _y (t)a _tx (t) a _ty (t) ] ^T , where r(t) is the relative distance of the projectile, v(t) is the approach velocity of the projectile, and at ( _t ) is the target acceleration. The motion model of the target adopts the "current" statistical model to establish the dynamic model of the pursuit system:

in

α represents the inverse of the maneuvering time constant, that is, the maneuvering frequency.

u(t)=[a _mx (t) a _my (t)] ^T

u(t) is the acceleration of the missile;

C=[0 0 0 0 α α] ^T

w(t)=[0 0 0 0 w _tx w _ty ] ^T

的白噪声。其中

σ_a分别为“当前”统计模型中目标机动加速度的均值和方差。Here w(t) is mean 0 and variance is

white noise. in

σ _a are the mean and variance of the target maneuver acceleration in the "current" statistical model, respectively.

The measurement information only includes the line-of-sight angle information, and the observation equation is:

z(t)=h(x)+v(t)

After discretization, we can get

observation equation

z(k)=h[x(k)]+v(k)

v(k) is the measurement noise, which is a Gaussian white random vector sequence.

(2) Use the particle filter estimation algorithm to estimate the state of the target, the number of particles N=1000, and obtain the state of the target, including information such as position, speed, and acceleration.

(3) At present, only the distribution of the target in the y direction is considered, because the target can hit the target as long as the missile and the target are at the same height. Here, it is assumed that the current acceleration of the target in the y direction is a _E (t _k ), and the target acceleration a _E (t _k+1 ) at the next moment is mainly distributed in its field, and its distribution obeys the gamma distribution

where a(b-1)=a _E (t _k )+a _Emax and the current acceleration satisfies a _E (t _k )∈[-a _Emax ,0], for a _E (t _k )∈[0,a _Emax ] In the case of , the probability density function is symmetrical with the above interval along the ordinate. The acceleration corresponding to the maximum probability is the current acceleration a _E (t _k ), and there is a _E (t _k )=ab+b-8.

So the probability density distribution of the predicted position of the target at the next moment is described as follows

Pr[y _E (t _k+1 |t _k )]=f(y _E (t _k ),Pr[a _E (t _k+1 )],t _k )

Figure 3 shows the probability distribution for different accelerations and different a, b values.

t_f时刻导弹所有可能状态集合为

y方向所能到达的所有集合为D(t_f,x_P(t_k+1|t_k))，导弹的最大可达区域都是导弹以最大加速度50g能力飞行构成的飞行包线在y方向的分布。图4显示的是导弹与目标还有干扰的飞行可达区示意图。(4) Predicted state of missile at time t _k+1

The set of all possible states of the missile at time t _f is

All sets that can be reached in the y direction are D(t _f ,x _P (t _k+1 |t _k )), and the maximum reachable area of the missile is the flight envelope formed by the missile flying with the maximum acceleration of 50g in the y direction. Distribution. Figure 4 shows a schematic diagram of the flight reachable area of the missile and the target as well as interference.

(5) Propose performance functions according to interception requirements

The meaning of the performance function is the probability integral that both true and false targets are included in the missile reachable area, ensuring that the maximum performance function means the maximum probability of approaching the target.

The optimal position of the missile at the next moment is

(6) The missile control command is

u(t _k )=u _y (t _k )/cosθ _P

θ _P = arctan(v _Py /v _Px )

_{Dy =} [0 1 0 0 0 0]

_Dvy = [0 0 0 1 0 0]

The initial conditions of the simulation are: the initial target position x and y directions are respectively x _E (t ₀ )=8000m, y _E (t ₀ )=6000m, and the initial speed x and y directions are respectively v _Ex (t ₀ )=400m/ s,v _Ey (t ₀ )=0. The initial position of the missile in the x, y direction is x _P = 0, y _P = 6000m, the initial speed in the x, y direction is x _Px = 1000m/s, v _Py =0. The burning time of the jamming bomb is 3s. Figure 5 is a schematic diagram of the ballistic trajectory of the target when t _go = 4.5s when the target drops the jamming bomb. Figure 6 is the comparison of the amount of misses when the target drops the jamming bomb at different times and the missile misses under different guidance laws. . It can be seen that the missile miss amount based on this method has better performance than the guidance method of tracking the energy center. Figure 7 is a schematic diagram of the ballistic trajectory of the target when t _go = 2s when multiple consecutive jamming bombs are dropped on the target, and Figure 8 is the target drop. The comparison of the remaining flight time t _go after multiple jamming bombs in succession and the miss miss amount of the missile under different guidance laws.

Claims (1)

1. An anti-interference guidance method of an infrared air-to-air missile based on target terminal reachable region prediction is characterized by comprising the following steps:

(1) the infrared air-to-air missile seeker obtains measurement information of a target, filter estimation is carried out on target state information, and the residual flight time of the missile is estimated;

(2) assuming that the target acceleration follows the probability distribution of gamma distribution, and calculating the position distribution region of the target at the next moment and the meeting moment;

(3) calculating the reachable area of the missile at the next moment, and calculating the final moment of the missile at each possible position at the next moment with the maximum flight capacity

An area that can be reached;

(4) providing a missile control instruction which is calculated by taking a maximum probability hit target of the missile as a performance index and maximizing the performance;

(5) And (3) applying control to the missile, and returning to the step (1) for circulation until the missile meets the target.

Images