UA48843A - Adaptive filter for estimating parameters of a target trajectory - Google Patents

Abstract

The proposed adaptive filter for estimating parameters of a target trajectory contains a unit for estimating an error correlation matrix, a unit for parameter estimation, a memory, and a unit for parameter extrapolation. Additionally, in order to increase accuracy of estimating the target trajectory parameters and improve the target tracking, the adaptive filter contains a phasometer and a unit for measuring the target velocity and acceleration. This unit contains a reference functional signal former, a subtracting unit, a correlator, and a unit for estimating velocity and acceleration.

Description

Description of the invention

The proposed invention relates to the field of radar and can be used to estimate parameters 2 of the trajectory of a maneuvering target.

A well-known adaptive filter is a quasi-optimal parameter measuring device (1) that monitors the movement of a maneuvering target, which contains two channels (filters) for estimating the parameters of the target's movement, respectively, in the absence and presence of the target's maneuver, as well as a channel for detecting and evaluating the maneuver. The resulting estimates of the trajectory parameters are found as weighted average values of the estimates taking into account the probability of the maneuver. 70 The disadvantage of this device is that estimates of the trajectory parameters are formed on the basis of a posteriori filtering errors, after several radar surveys, which leads to a significant delay in determining the time of the start and intensity of the maneuver, and, accordingly, to significant dynamic filtering errors.

The closest to the proposed technical solution, selected as a prototype, is an adaptive filter for estimating the trajectory parameters of a maneuvering target, |2), which includes in its composition: a block for estimating the correlation 12 matrix of errors, a block for estimating the trajectory parameters, a device that remembers and the trajectory parameters extrapolation block.

In this device, tracking and estimation of the parameters of the target trajectory is carried out according to the recurrent scheme of the linear Kalman filter. At the same time, several extrapolated parameter values for different possible maneuver intensities are calculated simultaneously.

The disadvantage of this device is that the assessment of the presence and intensity of the maneuver is made on the basis of a comparison of the extrapolated and measured values of the target coordinates. At the same time, the specified accuracy of parameter estimation is achieved only after several periods of radar inspection, i.e. with significant dynamic filtering errors, which can lead to the failure of tracking.

Thus, in the prototype, the detection of the maneuver and the assessment of its intensity is carried out based on a posteriori filtering errors (on the inconsistency of the measured and extrapolated values). At the same time, the dynamic "error of range estimation can reach the value of 1. and the radial velocity - up to 40Ω/s (11.

The invention is based on the task of creating such an adaptive filter for estimating the parameters of the target’s trajectory, in which the introduction of new blocks, namely the phase meter blocks and the node for estimating the speed and acceleration of the target, will allow for timely detection of the target’s maneuver and assessment of its intensity, thereby increasing the accuracy of the measurement of the C parameters the trajectory of the target and the stability of its support. (se)

The technical result that can be obtained when using the invention consists in the possibility of increasing the accuracy of measuring the parameters of the target's trajectory and the stability of its tracking. co

The task is solved due to the fact that the unit containing the correlation and error matrix evaluation unit, as well as the parameter evaluation unit, the memory device (ZP) and the parameter extrapolation unit are additionally connected in series the phase meter block and the target speed and acceleration estimation node as a part of the serially connected reference function generator block, calculation blocks, correlator and estimate formation, while the output of the phase meter block is connected to the second input of the calculation block 70, and the output of the estimate formation block is the second input of the parameter extrapolation block. - c The introduced blocks allow to measure the value of the phase function of the signals ф based on the sequence of pluna-signals received during one radar inspection, and then, by means of correlation processing, to obtain estimates of acceleration, which characterize the presence and intensity of the target's maneuver, and to use them for more timely and accurate estimation of trajectory parameters. At the same time, the dynamic range and speed filtering errors are reduced several times and the stability of tracking the maneuvering target is increased. Fig. 1 shows the structural diagram of the proposed device. Figure 2 shows typical phase functions of the echo-signals and reference phase functions. Figure 3 shows the results of correlation processing of a typical function of the phase of echo signals. (ee) The proposed device (Fig. 1) contains a block for calculating the correlation matrix of errors 1, 50 of them are connected in series, a block for calculating parameter estimates 2, a memory device (ZP) 3, a parameter extrapolation block 4, and a phase meter block 5 and the speed and acceleration estimation node 10 as a part of the serially connected blocks of the support function generator (SOF) 6, the calculation 7, the correlator 8 and the formation of estimates 9, and the output of the parameter extrapolation block 4 is connected to the second input of the parameter estimation block 2 , the output of the phase meter block 5 is connected to the second input of the calculation block 7, and the output of the estimate formation block 9 is connected to the second input of the parameter extrapolation block 4, the inputs of the device are the inputs of the error correlation matrix estimation blocks 1 and parameter estimations 2, as well as the input of the block phase meter 5, the outputs of the device are the outputs of the error correlation matrix evaluation unit 1 and the parameter evaluation unit 2.

The operation of this device is as follows:

During the next (nth) inspection of the radar, a sequence of echo-signals from the accompanied target х) is received at the input of the device, as well as the values of the coordinates of the target х and their variances measured from this sequence

ERROR sop at the time id.

Monitoring and evaluation of the parameters of the target's trajectory is carried out according to the recurrence relations of the linear Kalman filter |21.

In the extrapolation block of parameters 4, on the basis of calculated estimates obtained during the time of tracking the target in the previous (n-1) radar surveys and stored in (ZP) Z, the extrapolated values of the coordinates of the target are calculated.

And 27

Hu Khv koh t55 ho, (E8)

Ho Khad t. X, where ta is the extrapolation time of the parameters, .. - respectively, the estimation of the values of the trajectory parameter and its derivatives.

Чхх 70 The amount of acceleration .. characterizes the presence and intensity of the target's maneuver. h

Acceleration is estimated by correlation processing of the phase function of the sequence from echo signals. The values of the phase function fu, where i - 1, 2, ... t are determined in the phase meter block 5 by measuring the phase of the echo signals relative to the phase of the sounding signal: 515 of them

F, - Fu fu 2, push Ki, UC, U c) where y, - wavelength, and - delay time of the ith echo-signal, ... - parameters of the target's trajectory - range, speed and acceleration. ov p.

The type of phase function of the sequence of echo signals is shown in Fig. 2, it depends on the parameters of the trajectory "The estimation of the speed and acceleration parameters is made by the method of comparing the phase function Phi Z

Kok by a set of M reference (reference) functions of the Fopi| phase The comparison is carried out by calculating M values of the correlation integral: « 1 т 2 т 2 шу -4| In VipAf, | In sovaf, | . (3) ti ii s - bo ii- . de Afu fi Fonukh 212, M; "And 47 in 1 I (ee)

Fopi ot hu Kovi T ), (4) (ee) ; Ar. grew up

Ku - AK, Kom t /AKov, (5)

T-period of signal repetition, 05. - discreteness of speed and acceleration reading. The values of the reference functions ( Fopi are formed in the block

АВАВР " of the generator of support functions 6, and the value of the difference Аф In the calculation block 7. - s The calculation of the values of the correlation integral is carried out in block 8. The cross section of the body of uncertainty, "from obtained from the values of y), is shown in Fig. 3. " As an estimate of the values radial velocity and acceleration parameters are accepted in I e of that reference

Ge Fa function, when compared with which the maximum value of the correlation integral is obtained: т-Ш tah - tah uz. (mu (6)

The acceleration value characterizes the presence and intensity of the target's maneuver. 1.

Ge) and and k

They are used when calculating the extrapolated values of the target trajectory parameters in accordance with (1). t In the evaluation block of the correlation matrix of errors (CEM) 1, the values of the elements of the CEM are calculated: m - t « M FvF, from (7) where Fu, is the extrapolation matrix, shp-i 7 correlation matrix of errors obtained by (n-1)- oh steps In parameter estimation block 2, on the basis of the values of parameters ху measured at the n-th step and the extrapolated values obtained. are formed in hop heap estimation of trajectory parameters:

Hu - Khzp no Ah, -khyuH (9) in 5

Kha t Khap that ВХ, Хо) where А"В" are filter gain coefficients, formed on the basis of KMP values and variances of measurement errors using ratios for a linear Kalman filter (21.

In the technical implementation of the proposed device, the following typical nodes and blocks 65 of radio-electronic equipment can be used.

Blocks for estimating the correlation matrix of errors 1, estimating the trajectory parameters 2, the memory device 3,

extrapolations of parameters 4 can be performed as in prototype (2) based on a set of typical microcircuits for calculating arithmetic operations |Z.

The phase meter block 5 is made in the form of a standard "phase-code" converter |4).

Blocks of generator of reference functions 6, subtraction 7, correlator 8 and formation of estimates 9 ensure the execution of arithmetic and logical operations, as well as the calculation of trigonometric functions in accordance with expressions (3)...6) and can be performed on the basis of typical microcircuits |З| or on the basis of a microprocessor.

The sequence of inclusion in the operation of individual blocks of the device and the order of their interaction at the corresponding stages of processing, as well as the order of recording and removing information is determined and ensured by a grid of control and 7/0 synchronizing pulses "tied" to the grid of the radar synchronizer (synchronization and control node on not shown in the diagram).

The positive effect of using the proposed device can be evaluated using the example of a typical decimeter range surveillance radar.

For radar parameters with a wavelength of 75, - 0.5 m, repetition period T - 1 Ohms, inspection period Te - 203, 7/5 of the width of the antenna's directional pattern in the azimuthal plane AEovr7 1h, the target irradiation time is 5 bOhms. At the same time, a coherent bundle of up to 50 echo signals can be obtained for one target in one examination.

The accuracy of measurement of the radial velocity and acceleration along the coherent bundle is |5): . t ISHNY ank--- -1/k t . 23x When accounting for the maneuver of the target using this information, the dynamic error of the evaluation of the vln, mot? range in the proposed device is the value of ,la on the radial speed vy - vnu - OV, and shy at the intensity of the target's maneuver. In the prototype, there are significantly more errors than in "

VE - 40/th ve- 40/th to the proposed device. In addition, when the strobe value of DK - Zbr - Zkm escort will be disrupted from escorting the maneuvering target.

References: see 1. Tikhonov V.I., Harpov V.N. Statistical analysis and synthesis of radio engineering devices and systems. - M.:

Radio and communication, 1991, - 550 p.. t 2. Kuzmin S.3. The basis! design of systems for digital processing of radar information. - M.: (se)

Radio and communication, 1986. - 182 p. 3. Digital and analog integrated microcircuits. Directory. Ed. S. V. Yakubovsky, - M.) Radio and communication, 19907546 p. "And 4. Gitis Z.I. Information converters for ZCVM. - M.; Energy, 1975-323 p. 5. Signal processing in multi-channel radars. Ed. A.P. Lukoshkina.-M.: Radio and communication, 1983 - 197 p. "du

Claims (1)

The formula of the invention with and Adaptive filter for estimating the parameters of the target trajectory, which contains a block for calculating the correlation matrix "" of errors, a block for calculating parameter estimates, a memorizing device, and a parameter extrapolation block, which is distinguished by the fact that an additional block is introduced phase meter and Velocity and acceleration estimation node as part of serially connected blocks of the generator of reference functions, the subtraction block, "g" correlator and the block of forming estimates, and the output of the parameter extrapolation block is connected to the second input of the parameter estimation block, the output of the phase meter block with connected to the second input of the subtraction block, and the output of the estimate formation block to the second input of the parameter extrapolation block, the inputs of the device are the inputs of the error correlation matrix evaluation blocks (ee) and the first input of the parameter estimation block, as well as the input of the phase meter block, their 50 device outputs there are outputs of the error correlation matrix estimation and parameter estimation blocks. R 60 b5