SU987543A1 - Signal detector - Google Patents

Description

 The invention relates to a radio range and can be used in polotom pulsed radar stations to detect fluctuating signals against an additive mixture of white noise and correlated passive interference with unknown correlation coefficients and dispersion. A signal detector is known, containing N receivers, N calculators, first, second and third adders, a delay line, a first multiplier and a subtractor, and the output of each of the N receivers is connected to the input of the same name body, each of which contains a delay line multiplier and main quadra. However, the known signal detector has low noise immunity when exposed to correlated passive interference. The purpose of the invention is to increase the noise immunity in the presence of correlated passive interference. The goal is achieved by the fact that the signal detector containing N receivers, N calculators, the first, second and third adders, delay line, first multiply k) the subtraction unit, and the output of each of the N receivers is connected to the input of the same calculator, Each one of you isters contains a delay line 1, a multiplier and a main quad. introduced the second multiplier, the first quadrant and consistently included. an addition unit, a second quadrant and a threshold block, and an additional quad is introduced in each of the N calculators, with the first output of each of the N calculators connected; with the corresponding j of the N inputs of the first adder, the output of which is through the series-connected first multiplier. The 3E subtraction unit and the delay line are connected to the first inputs of the complex and the second multiplier; the second output of each of the N computers is connected to the corresponding one of the N inputs of the second adder, the output of which is connected to the second quadrant, the third output of each from N, the computers are connected to the corresponding one from the N blocks of the third adder, the output of which is connected to the second input of the first multiplier, the output of the subtraction unit is connected to the second inputs of the stratum block and the second multiplier, the output of which th is connected to the second input of the threshold unit. and in the calculator, the output of the delay line is connected to the input of the main quad and the first input of the multiplier, the input of the delay line is connected to the input of the additional quad and the second input of the multiplier, and the input of the calculator and the first, second and third outputs are respectively quadra of the torus, the output of the multiplier yi is the output of the additional quad. FIG. 1 shows the structural electrical circuit of the proposed device; in fig. 2 - detection characteristics (solid curves of the proposed device, intermittent known device; s / n - signal ratio / correlated interference in power; D - probability of correct detection; R - correlation coefficient of passive interference; F - probability of false alarm; N is the number of frequency channels; the number of adjacent channels of the range); in fig. 3 shows the dependence of the threshold signal Uyj (dB) on the value of the correlation coefficient R. The signal detector contains N receivers 1, N calculators 2, the first, second and third adders 3-5, 6-Delay line, the first multiplier 7, block 8 subtraction, the second multiplier 9, the first and second quadrants 10 and 11, the adding block 12, the threshold block 13, each of the N calculators 2 contains the delay line 14, the main and additional quadrants 15 and 16, and the Signal Detector multiplier works as follows. 3. The reflected complex multi-frequency signals entering the device are divided in N receivers 1 in frequency into component subsignals and amplification, detection, delay of signals are performed in order to compress the resulting signal, and also to center it. Next, the sub-signals go to the inputs of the N computers 2. In the computers, 2 sub-signals go to the delay line 14, additional quadrants 16 and to the second inputs of the multipliers 17, the delays delayed by the 14 lines for one repetition period go to the main squares 1b and to the first inputs multipliers 17. Thus, at the moment of time corresponding to the observation of a certain point of the probing space, at the first outputs of each of the N calculators 2, there will be | corresponding to the previous repetition period the squares of deviations of the subsignals from the average, iHa of the second, the products of the deviations of the values of the subsignals by the averages in the previous and current repetition periods, and on the third, the squares of the deviations in the current repetition period. In the first, second and third adders 3,4,5, the statistics obtained for each subsignal are added: in the first - the squares of deviations in the previous period, in the second - the products of deviations in the previous and current periods, in the third - the squares of deviations in the current period. Thus, the signals at the outputs of the summation block are proportional; in the first, the estimate of the dispersion of the signal in the previous period; in the second, the estimate of the signal covariance between the previous and the current period; in the third, the estimate of the dispersion of the signal in the current period. The proportionality factor for all signals at the outputs of block 8 is the same and equal to the number of reception channels. The signals supplied to the first multiplier 7 from the outputs of the first and third adders 3 and 5 are multiplied together, and the signal from the output of the second adder 4 is squared in the first quad 10 and fed to the second input of the subtraction unit 8, the first input of which is output from the output the first multiplier 7. The signal at the output of block 8 to read the rotation of the difference between the signals at its first and second inputs is proportional to the estimate of the determinant of the covariance matrix of the signal for the considered case of observing the signal in two periods , defined by the expression ь, the estimate of the signal's expres- sion in the previous period of repetition in this element of the resolution or in range; 01.- estimate of the dispersion of the signal in the current repetition period in this element of the resolution in range; R is the estimate of the interperiod correlation coefficient in a given distance resolution element. From the output of block 8, the signal enters the input of delay line 6, the second input of the second multiplier 9, and the second input of block 12. Delayed by one element of the resolution on the range of the output signal line .6. delays are fed to the first input of the addition unit 12 and to the first input of the second multiplier 9; from the output of the addition unit 12, the signal is fed to the second quadrant 11. The signal at the output of the second multiplier 9 is determined by the expression and, (-.), (0 la where Q - the estimation of the variance of the signal of the previous period in the previous element of the resolution by the distance; C is the estimate of the dispersion of the signal of the current period in the previous element of the resolution of the distance K — the estimate of the interperiod correlation coefficient in the previous element of the resolution of the range. The second square 11 is defined by the expression wxH..C1- a) Xa; The ratio of signals (2) and (1) in the case when the parameters of the RR interference in both elements of the range resolution are the same, has a distribution that does not depend on the values of these parameters, the distribution points are constant, depending only on the number of receive channels N. ... The signal from the output of the second multiplier 9 is fed to the second input of the threshold unit 13 and is control. The decision threshold is determined by the magnitude of the control voltage and the constant coefficient of proportionality determined by the number of reception channels and the specified probability of false alarms. A signal from the output of the second quadrant 11 is supplied to the first input of the threshold unit 13, in which it is compared with the threshold. The presence of the useful signal from the circuit in one of the viewed neighboring elements changes the values of the parameters (Y and R interference in this resolution element, the probability distribution of the ratio of voltages (2), and (1) changes, becomes dependent on parameters 0 and R , in this case, the distribution moments increase and the threshold is exceeded by a signal, and a signal appears at the output of the threshold unit 13, which is judged on the presence of a signal. A comparative analysis of the known and proposed devices has been shown (Fig. 2 and Fig. 3 ) that the average gain in noise immunity when using the proposed device is 7, 9 dB, for the case of using two () time channels. Foriula of the invention Signal detector containing N receivers, calculators, first, second and third adders, delay line, first multiplier and a subtraction unit, wherein the output of each of the N receivers is connected to the input of the same name calculator, each of the calculators contains a delay line, a multiplier and a main quad, characterized in that, in order to increase the in the presence of correlated passive interference, the second transducer is introduced into the detector, the first quadrant and the series of addition, the secondary quad and the threshold block, and an additional quad is introduced into each of the N computers, the first output of each of the N computers being connected to the corresponding N inputs of the first adder, the output of which is connected through the series-connected first multiplier, subtraction unit and delay line to the first inputs of the addition unit and the second multiplier, the second output Each of the N computers is connected to the corresponding 1S from the N by entering the second adder, the output of which is connected to the second input of the subtractor through the first quadrant of the soye, the third output of each of the N computers is connected to the corresponding of the N inputs of the third distributor the input of the first multiplier, the output of the subtraction unit is connected to the second inputs of the addition unit and the second multiplier, the output of which is connected to the second input of the threshold unit, and in the calculator the output of the delay line is connected to the input of the main input a squarer and a first input of multiplier, a delay line input is connected

with the input of an additional quad and the second input of the multiplier, and the input, the house, and the first, second, and third outputs of the calculator, respectively, are the input of the delay line, the output

the main quad, the multiplier output and the output of the additional quad.

Sources of information coming into consideration during the examination

 1. US patent N 4047172,

cl. ,one. R, publish. 09/06/07 (prototype).

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Claims (1)

Claim A signal detector containing N receivers, calculators, first, second and third adders, a delay line, a first multiplier and a subtraction unit, wherein the output of each of the N receivers is connected to the input of the computer of the same name, each of the calculators contains a delay line, a multiplier and a main quadrator, characterized in that * in order to increase the noise immunity in the presence of correlated passive interference, a second ne 7 9 < a multiplier, a first quadrator and sequentially connected addition unit, a second quadrator and a threshold block, and an additional quadrator is introduced into each of N calculators, while the first output of each of N calculators is connected to the corresponding N inputs of the first adder, the output of which is through the first multiplier connected in series , the subtraction unit and the delay line are connected to the first inputs of the addition unit and the second multiplier, the second output of each of the N calculators is connected to the corresponding of the N inputs of the second adder, the output of which, through the first quadrator soy, is dined to the second input of the subtraction unit, the third output of each of the N calculators is connected to the corresponding of the N inputs of the third adder, the output of which is connected to the second input of the first multiplier, the output of the subtraction unit is connected to the second inputs of the addition unit and a second multiplier, the output of which is co5 connected to the second input of the threshold block, and in the computer, the output of the delay line is connected to the input of the main quad and the first input of the multiplier, the input of the delay line is connected to the input of The additional quadrator and the second input of the multiplier, and the input and the first, second and third outputs of the calculator, respectively, are the input of the delay line, the output of the main quad, the output of the multiplier, and the output of the additional quad.