JPH0252286B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the tracking function of a homing seeker for proportional navigation of a flying object, and in particular improves the angular tracking function of the seeker by performing information processing on a digital computer mounted on the flying object. The purpose is to improve the distance tracking function and to improve the miss distance of the flying object.

Proportional navigation is often used to guide and control flying objects. This proportional navigation is based on the principle that if the viewing angle of the target from the flying object is constant, the two will collide, and the flying object is guided and controlled so that the viewing angle of the target is always constant. Therefore, the course of the flying object is constant unless the line-of-sight angle changes, and the lateral acceleration command value when the line-of-sight angle changes is as follows.

(Lateral acceleration command value) = (navigation constant) x (relative velocity between flying object and target) x (target line-of-sight angular velocity) Figure 1 shows the target line-of-sight and the seeker antenna boresight on a two-dimensional plane. Indicates the relationship with the axis.
In the figure, the X axis is the reference axis, 1A is the target line of sight, 1B is the antenna boresight axis, 2A is the tracking error angle, and 2B
indicates the line of sight angle, and 3A is the seeker who is about to fly.
The antenna position, 3B, represents the target position. FIG. 2 shows the relationship between the antenna coordinate system and the target eye line coordinate system. In the figure, three orthogonal axes (r, e, d) indicate the antenna coordinate system, and three orthogonal axes (r', e', d') indicate the target eye line coordinate system. Here, 4A represents an azimuth tracking error, and 4B represents an elevation tracking error.

Now, in the angle tracking control system used in conventional homing seekers for proportional navigation of flying objects, the angular error signal between the flying object and the target using the conical scan method or the monopulse method is passed through a gain correction circuit. After that, it was sent to the antenna space stability loop, and the antenna space stability loop was an analog negative feedback method that reduced the angle error to zero by driving the antenna gimbal servo hydraulically or electrically based on this rate command value. .

FIG. 3 shows a block diagram of a flying object guidance system using a conventional analog tracking system. 5 represents the spatial movement of the target, and 6 represents the relative movement between the target and the flying object. 7A and 7B represent the target eye line angular velocities around the d' and e' axes in FIG. 2, ie, ω _LSd ' and ω _LSe ', respectively, and are so-called δ _x and δ _y components. 20A and 20B represent the d-axis and e-axis components of the spatial angular velocity of the seeker antenna, namely ω _Ad and ω _Ae , and the difference between 7A and 20A and 7B
The difference between and 20B, ie, 8A and 8B, indicates the differential values of the tracking error angles ε _d and ε _e , respectively. Therefore 9A,
Outputs 10A and 10B of the integrator indicated by 9B indicate the azimuth tracking error and the elevation tracking error ε _d and ε _e , respectively. 12 surrounded by a dotted line indicates the angle error receiving section/filter section of the seeker, and 11A and 11B are the respective channels (for azimuth angle tracking and elevation angle tracking).
shows the receiver noise of 13A and 13B indicate the loop gain of each tracking channel, and the output thereof creates a spatial angular velocity command value of the antenna air recording stabilizer 14. 15 represents the spatial angular velocity motion of the flying object, and the output of 14 produces the spatial angular velocity components 20A, 20B of the seeker antenna, ie, ω _Ad , ω _Ae . On the other hand, the antenna spatial angular velocity command value outputted from 13A and 13B produces a lateral acceleration command signal for the flying object according to the guidance law using proportional navigation shown at 16A and 16B. Here, 17 is a distance rate gate output signal obtained from a distance/distance rate receiving section for measuring the distance between the flying object and the target and the distance rate. The flying body lateral acceleration command signals generated by 16A and 16B generate lateral acceleration on the flying body through the lateral movement of the flying body autopilot aircraft indicated by 18A and 18B, respectively. 19A,
The aircraft performs an aerodynamic flight motion under the limitations of the G-limiter of the aircraft, indicated by 19B, and is guided by proportional navigation so as to keep the target line-of-sight angular velocity constant based on the relative movement of the target and the missile in 6. On the other hand, the relative distance to the target and the distance rate are 24A, respectively.
24B, that is, R, R〓, which are measured by the distance/distance rate receiving section surrounded by the dotted line 21 and tracked by the distance gate output and distance rate gate output signals shown at 25 and 17, respectively. Here, 22 and 23 indicate receiver noise of the distance/distance rate receiving section.

This conventional method detects the angular error signal caused by the relative movement between the target and the flying object carrying the seeker, and applies feedback to reduce the error to zero, and is used as a tracking system. constitutes a first-order lag system. Therefore, when the angular velocity of the eye's line of sight due to intense movement of the target is high, the tracking error angle becomes large, and there is a risk that tracking may be lost. Therefore, if you reduce the time constant of the loop including the gain correction circuit or increase the loop gain in order to speed up the response of the tracking loop, this has the disadvantage that the tracking loop becomes unstable due to receiver noise, and the tracking loop naturally becomes unstable. It had limited functionality.

In view of the above points, the present invention mounts a digital calculator on a flying body, converts a raw angle error signal, a distance signal, and a distance rate signal into digital signals, and generates an estimated value of receiver noise at the reception level at that time. is used to calculate the estimated rate of change of the target eye gaze angle, the estimated angular error, the estimated distance and distance rate, and use these estimated values to perform guidance by proportional navigation to avoid misdistance. The present invention also aims to provide a flying object guidance control method that improves the tracking function.

Embodiments of the flying object guidance and control method according to the present invention will be described below with reference to the drawings.

The major difference between the present invention and conventional analog tracking systems is that an optimum filter is incorporated as software in the on-board digital computer after each receiving section of the angle tracking system and distance/distance rate tracking system.
FIG. 4 shows a block diagram of an embodiment of the present invention. In this figure, 26 indicates the spatial motion of the target, and the linear approximate dynamics equations representing the relative geometric motion between the target and the flying object in 27 are as follows for the angle tracking system and the distance/distance rate tracking system, respectively. It is written as follows.

d〓 _A ／dt＝〓〓 _A ＋〓 _A ＋〓 _A 〓 _A …(1) However Here, the elements of the state variable _A ; ε _d and ε _e are the azimuth tracking error and the elevation tracking error, ω _LSd ′, ω _LSe ′ are the d′-axis and e′-axis components of the target eye line-of-sight angular velocity, a _Td ′ , a _Te ′ indicate the −d′-axis and e′-axis components of the target acceleration, both of which are random variables. Elements of deterministic vector 〓 _A ; ω _Ad , ω _Ae
are the d-axis and e-axis components of the spatial angular velocity of the seeker antenna, and a _Id and a _Ie are the d-axis and e-axis components of the acceleration of the flying object. 〓 _A indicates the input constraint matrix, which is determined by the characteristics of the tracking target. Input vector to tracking target〓 _A
The elements; W _d ′ and W _e ′ represent white noise that drives the target acceleration model. Also, the elements of the coefficient matrix 〓;
ω _Ar is the r-axis component of the spatial angular velocity of the seeker antenna, R is the distance, R〓 is the range rate, and τ _d ′ and τ _e ′ are the target rotation time constants. Similarly, the distance/distance rate tracking system is d〓 _R /dt=〓・〓 _R +〓 _R +〓 _R・Wr′ …(2) However, 〓 ^T _R = [R, R〓, a _Tr ′] 〓 ^T _R = [0, −a _Ir , 0] 〓 ^T _R = [0, 0, 1] 〓 = 0 ω ² _Ls 01 0 00 1 −1/τ _r ′ Here, state variable 〓 Element of _R ; a _Tr ′ is the r′-axis component of the target acceleration, the element of the deterministic vector 〓 _R ; a _Ir is the r-axis component of the missile acceleration, 〓 _R is the input constraint matrix, which is determined by the properties of the tracking target, and W _r ′ is the target acceleration Shows white noise driving the model. Also, the element of the coefficient matrix 〓; ω ² _Ls is given by ω ² _Ls = ω ² _Lsd ′+ω ² _Lse ′. τ _r ′ represents the turning time constant with respect to the target acceleration. If the homing seeker of the flying object has a 3-axis gimbal or the roll stability of the flying object's autopilot is sufficient, then
The element ω _Ar of the coefficient matrix 〓 of the dynamics equation given by equation (1), that is, the r-axis component of the spatial angular velocity of the seeker antenna can be ignored. Therefore, equation (1) can be separated into an azimuth channel and an elevation channel, which can be expressed as the following equations.

d／dt〓 _A ′＝〓′〓 _A ′+〓 _A ′+〓 _A ′W _e ′ …(3) However, 〓 ^T _A ′＝[ε _d , ω _Lsd ′, a _Te ′] 〓 ^T _A ′＝ [−ω _Ad ,−a _Ie /R,0] 〓′=0 0 01 −2R/R 00 1/R −1/τ _e ′ 〓 ^T _A ′=[0,0,1] Similarly, d/ dt〓 _A ″＝〓″〓 _A ″＋〓 _A ″＋〓 _A ″W _d ′ …(4) However,〓 ^T _A ″＝［ε _e , ω _Lse ′, a _Td ′］ 〓 ^T _A ″＝［− ω _Ae ,a _Id /R,0] 〓=0 0 01 −2R〓/R 00 1/R −1/τ _e ′ 〓 ^T _A ″[0,0,1] Now, the dynamics of the 27 angle tracking system equation
The target eye line angular velocity in equations (3) and (4); ω _Lsd, , ω _Lse ′ is
The spatial angular velocities ω _Ad and ω _Ae of the seeker antenna are shown as 50A and 50B. The difference between 28A and 50A and the difference between 28B and 50B, ie, 29A and 29B, represent the differential values of the tracking error angles ε _d and ε _e as in the analog tracking system.
Therefore, the tracking errors ε _d and ε _e are represented by 30A and 30B obtained by integrating 29A and 29B once by integrators 70A and 70B. 32 surrounded by a dotted line indicates the angle error receiving section of the seeker, and 31A and 31B indicate receiver noise of each channel. The observed value of angular error is obtained when S·W1 is closed. This observed value becomes an input signal to an optimal filter ( ) (also called a Kalman filter) indicated by 34 configured as software of the on-board digital computer indicated by 33 surrounded by a dashed line. The optimal filter ( ) 34 calculates the estimation error based on the discrete-value system dynamics equation converted from the continuous-system dynamics equation representing the relative geometric motion between the target and the flying object expressed by equations (3) and (4). A repeating type discrete value filter is constructed that satisfies the criterion of minimizing the square. The discrete-value system dynamics equation is given by the following equation for the azimuthal channel.

〓 _A ′ (K + 1) = Φ _A ′ (K + 1, K) 〓 _A ′ (K) + 〓 _A ′ (K) + 〓 _A ′ (K) W _e ′ (K) …(5) Here, Φ _A '(K+1,K) represents a transition matrix and is given as shown in the following equation.

(However, Δt=t _k+1 −t _k ) Similarly, the deterministic vector 〓 _A ′(K) and the input constraint vector 〓 _A ′(K) are also given as follows.

It is obvious that the elevation channel is also given in the same way, so the description thereof will be omitted.

Further, the filter input 35 indicates the observed value of the angular error, which is given by the following equation in the case of the azimuthal channel.

〓 _A ′(K+1)=〓 _A 〓 _A ′(K+1)+〓 _A ′(K
+1) ...(6) Or, Z _A ′ (K+1)=ε _d (K+1)+n _d (K+1) where 〓 _A represents the observation matrix, which in this case is given by the following equation. 〓 _A ′(K+1) indicates observation noise.

〓 _A = [100] Similarly, it can be seen that the filter input 36 is given by the following equation in the case of the elevation channel.

〓 _A ″(K+1)=〓 _A 〓 _A ″(K+1)+〓 _A ″(K
+1) ...(7) Or, Z _A ″(K+1)=ε _e (K+1)+n _e (K+1) When the equations (5) and (6) are given, the optimal filter ( ) 34 is given as the following equation. It is known that

〓 _A ′(K+1)｜K+1)=〓 _A ′(K+1｜K)
+〓 _A (K+1) {〓 _A ′(K+1)−〓 _A 〓 _A ′(K+
1｜K)｝ …(8) 〓 _A ′(K+1｜K)=Φ^ _A ′(K+1,K)〓 _A ′
(K｜K)+〓 _A ′(K) …(9) 〓 _A (K+1)=〓 _A (K+1｜K)〓 ^T _A [〓 _A 〓 _A
(K+1｜K)〓 ^T _A +R _A (K+1)] ^-1 …(10) 〓 _A (K+1｜K) Δ E[〓 ¹ _A (K+1｜K)
〓′ ^T _A (K+1｜K)] …(11) However, 〓 _A ′(K+1｜K)=〓 _A ′(K+1)−〓 _A ′(K
+1 | K) …(12) Prior estimation error covariance matrix defined by equation (11) 〓 _A
(K+1|K) satisfies the following equation.

〓 _A (K+1｜K)=Φ^ _A ′(K+1,K)〓 _A
(K｜K) ×Φ^′ ^T _A (K+1,K)+〓 _A ′(K)Q _A
(K)〓′ ^T _A (K) …(13) Posterior estimation error covariance matrix of equation (13)〓 _A (K｜
K) is defined as follows.

〓 _A (K｜K) Δ E[〓 _A ′(K｜K)〓′ ^T _A (K｜
K) …(14) However, 〓 _A ′ (K | K) = 〓 _A ′ (K) − 〓 _A (K | K)
...(15) Also, _A (K|K) defined by equation (14) satisfies the following equation.

〓 _A (K | K) = [−〓 _A (K)〓 _A ]〓 _A (K |
K−1) …(16) Here, Φ^ _A ′(K+
1, K), 〓 _A ′(K), 〓 _A ′(K) are the elements of Φ^ _A ′(K+1, K), 〓 _A ′(K), 〓 _A ′(K) in equation (5), respectively. R and R〓 are the optimal filters () for the distance/distance rate tracking system, that is, the outputs R(K) and R(K) of 57
means that it has been replaced by . R _A (K+1) in equation (10) represents the variance of observation noise as shown in the following equation. That is, [E[n _d (K+1)] = 0 E[n _d (K+1) n _d (K+1+J)] = R _A (K+1) δ _K+1

Claims (1)

[Claims] 1. In a flying object guidance control method in which a flying object is guided by proportional navigation using an angular error signal, a distance signal, and a distance rate signal of a homing seeker of a flying object, the homing seeker detects and tracks a target. When entering the tracking mode, the raw angle error signal containing noise for maintaining tracking, the raw distance signal, and the raw distance rate signal are converted into digital signals, and the reception level of the receiver in the tracking mode is The variance (power value) of the receiver noise in the state estimation algorithm programmed in advance in the digital computer mounted on the flying object is estimated by estimating the S/N ratio of the raw angular error signal. and the raw range signal, the raw range rate signal, and the estimate of the variance of the receiver noise. 1. A method for guiding and controlling a flying object, characterized in that the estimated values of the distance, distance, and distance rate are obtained, and these estimated values are used to execute guidance by proportional navigation.