CN107917646B - Infrared air-to-air missile anti-interference guidance method based on target terminal reachable area prediction - Google Patents

Abstract

The anti-interference guidance method of the infrared air-to-air missile based on the target future position prediction comprises 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 of the target at the next moment and the meeting moment; (3) calculating the position of the missile which possibly appears at the next moment, and calculating the region which can be reached at the meeting moment by the maximum flight capacity at the position of the next moment; (4) calculating the position of the missile at the next moment corresponding to the area covered by the missile with the maximum probability by comparing the coverage area of the missile with the reachable area of the target; (5) calculating a control instruction of the missile according to the position of the next moment; (6) and (3) exerting control on the missile, and returning to the step (1) until the missile meets the target.

Description

Infrared air-to-air missile anti-interference guidance method based on target terminal reachable area prediction

Technical Field

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

Background

After a target aircraft is threatened by a missile, an interference missile similar to the spectral characteristic of the aircraft is thrown to improve the survival rate of the aircraft, and the infrared air-to-air missile is used for accurately hitting the target, needing to be anti-interfered by hardware and an algorithm and finally hitting the target accurately.

An infrared imaging guidance anti-interference analysis by Jiakurui et al and an anti-interference technology by an infrared imaging guidance head by Li Juan et al all introduce in detail how an infrared guidance head resists interference when being thrown into a target airplane, the target and the interference are identified by analyzing differences in characteristics such as frequency spectrum, motion, gray scale and spatial distribution, an infrared air-to-air Missile guidance method under the condition of interference is researched in an Arthur Vermeulen paper Missile avaidance manoeuvres with Simultaneous export discovery deployment, and the miss distance relationship of the guidance method for tracking an energy center under different operational environments is analyzed. Dionne studied the Guidance method based on Predictive control in case of a single chaff in the paper "Predictive Guidance for Pursuit-evolution engage investments Decoys". However, with the development of the infrared interference missile, the spectral characteristic and the motion characteristic of the infrared interference missile are more and more similar to those of an airplane, the interference is greatly improved from the appearance and the motion state, particularly when the accuracy of an infrared imaging seeker at a long distance is not high, a certain difficulty and error rate exist in identifying a target airplane and the interference missile through the infrared air-to-air missile seeker, and in order to improve the anti-interference capability of the infrared air-to-air missile and prevent the missile from being trapped by the interference missile, the guidance algorithm of the infrared air-to-air missile is required to be improved.

In order to improve the success rate of intercepting the target by the missile under the condition that the target cannot be accurately identified, the invention provides a guidance method based on prediction guidance. The guidance method is based on a predicted target and a future reachable area of an interfering missile, combines the reachable range of the missile, and calculates a guidance instruction by taking the reached area of a true target and a false target which cannot be distinguished covered by the maximum probability as an index, so that the target can be accurately hit under the condition that the target cannot be distinguished.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the anti-interference guidance method for the infrared air-to-air missile is provided, and the hit rate of the infrared air-to-air missile after the infrared air-to-air missile is interfered by a target.

The technical solution of the invention is as follows: an anti-interference guidance method of an infrared air-to-air missile based on prediction guidance comprises 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 maximum flight capacity of the missile at each possible position at the next moment at the final moment t_fAn 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;

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

Compared with the prior art, the invention has the advantages that:

(1) compared with the traditional anti-interference method, the method can be used in the interference identification end section, and can supplement the guidance problem that the infrared air-to-air missile cannot identify the true and false targets according to other characteristics;

(2) the method can make up the deficiency of the hardware of the seeker to a certain extent, for example, the target and the interference which are caused by low resolution cannot be identified;

(3) compared with a common anti-interference guidance method such as tracking a target and interfering a mass center, the method has higher accuracy and can improve the hit rate of the missile.

Drawings

FIG. 1 is a guidance flow chart of anti-interference guidance of an infrared air-to-air missile;

FIG. 2 is a two-dimensional planar model of missile versus target engagement;

FIG. 3 is a schematic illustration of an acceleration probability distribution of an object;

FIG. 4 is a schematic diagram of a missile accessible zone and a target likely-to-occur zone;

FIG. 5 shows the time t when the target is thrown into the interfering bomb_goBullet trajectory diagram of 4.5s

FIG. 6 is a comparison of the miss distance of the missile when the target throws the missile at different moments and the miss distance of the missile under different guidance laws.

FIG. 7 shows the target for the jamming of a bomb t_go2s bullet trajectory diagram

FIG. 8 shows the different remaining flight times t after the target has thrown the chaff_goAnd comparing the miss distance with the miss distance of the missile under different guidance laws.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

The invention has the following implementation steps:

1. first, the engagement model in FIG. 2 is established

Taking a two-dimensional plane pursuit model as a research object, and selecting x (t) ═ r as a state quantity_x(t) r_y(t) v_x(t) v_y(t) a_tx(t) a_ty(t)]^TWherein r (t) represents the relative distance of the bullet eyes, v (t) represents the approaching speed of the bullet eyesDegree of a_t(t) represents a target acceleration. The motion model of the target adopts a 'current' statistical model to establish a dynamic model of the pursuit system:

wherein

α represents the inverse of the maneuver time constant, i.e., the maneuver 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

where w (t) is a mean of 0 and a variance of

White noise of (2). Wherein

σ_aRespectively, the mean and variance of the target maneuvering acceleration in the "current" statistical model.

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

z(t)＝h(x)+v(t)

obtained after discretization

Equation of observation

z(k)＝h[x(k)]+v(k)

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

(2) And performing state estimation on the target by using a particle filter estimation algorithm, wherein the number of particles N is 1000, and obtaining the state of the target, including information such as position, speed, acceleration and the like.

(3) Only the distribution of the targets in the y direction is considered at present, because the targets can be hit only if the missile and the targets are guaranteed to be at the same height. Let it be assumed here that the current acceleration of the target in the y-direction is a_E(t_k) Next moment target acceleration a_E(t_k+1) Mainly distributed in the field, and the distribution follows gamma distribution

Wherein a (b-1) ═ a_E(t_k)+a_EmaxAnd the current acceleration satisfies a_E(t_k)∈[-a_Emax,0]For a_E(t_k)∈[0,a_Emax]In the case of (2), the probability density function is symmetrical to the above-mentioned interval along the ordinate. Wherein the acceleration corresponding to the maximum probability is the current acceleration a_E(t_k) And has a_E(t_k)＝ab+b-8。

The probability density distribution of the predicted position of the target at the next time instant is then described as follows

Pr[y_E(t_k+1|t_k)]＝f(y_E(t_k),Pr[a_E(t_k+1)],t_k)

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

(4) Missile t_k+1Time of day prediction state

t_fThe missile at all possible states is integrated

All sets reachable in the y-direction are D (t)_f,x_P(t_k+1|t_k) The maximum reachable area of the missile is the distribution of a flight envelope formed by the missile flying at the maximum acceleration capacity of 50g in the y direction. FIG. 4 is a schematic view of the flight reach of a missile with interference.

(5) Proposing a performance function according to the interception requirement

The meaning of the performance function is the probability integral of the true and false targets contained in the reachable region of the missile, and the maximum probability is close to the target when the performance function is guaranteed to be maximum.

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)

D_y＝[0 1 0 0 0 0]

D_vy＝[0 0 0 1 0 0]

The initial simulation conditions are as follows: the x and y directions of the initial position of the target are x respectively_E(t₀)＝8000m，y_E(t₀) 6000m, initial velocity x, y directions are v_Ex(t₀)＝400m/s，v_Ey(t₀) 0. The initial position x and y directions of the missile are x_P＝0，y_P6000m, initial speed x, y direction x_Px＝1000m/s，v _Py0. Wherein the burning time of the interference bomb is 3s, and figure 5 shows the target interference bomb throwing time t_goThe projectile trajectory diagram of 4.5s, and fig. 6 is the miss distance comparison between the target throwing the interfering projectile at different time and the miss distance of the missile under different guidance laws. It can be seen that the missile miss distance based on the method has better performance relative to the guidance method of tracking energy center, and fig. 7 shows that t is t when a target throws a plurality of continuous interference missiles_goFig. 8 shows different remaining flight times t after the target throws a plurality of consecutive interfering bombs_goAnd comparing the miss distance with the miss distance 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.

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