RU2831755C1 - Interference rejector-computer - Google Patents

Abstract

FIELD: computer engineering.

SUBSTANCE: invention relates to computer engineering and can be used in automated systems for performing complex mathematical operations in order to select signals from moving targets against the background of passive interference with unknown correlation properties. Interference rejector-computer comprises first, second and third delay units, complex adder, complex multiplier, Doppler phase meter, clock generator, weight coefficient calculator and weight unit, connected to each other in a certain manner and performing adaptive coherent processing of initial digital readings.

EFFECT: high efficiency of compensating for passive interference and selecting signals from moving targets against the background of passive interference with a priori unknown correlation properties.

1 cl, 10 dwg

Description

The invention relates to measuring equipment and information technology and can be used in automated systems for performing complex mathematical operations in order to isolate signals from moving targets against a background of passive interference with unknown correlation properties.

A radar device for detecting a moving target is known [Japanese Patent No. 63-49193, IPC G01S 13/52], which contains sequentially connected delay units, a complex number multiplier and a subtractor. However, this device has low efficiency in isolating a signal from a moving target.

The closest to this invention computer for rejecting interference [patent RU No. 2797653, IPC G06F 17/10], selected as a prototype, contains delay units, a complex adder, a complex multiplier and a Doppler phase meter. However, this device has losses in the effectiveness of interference compensation.

The problem solved in the invention is to increase the efficiency of rejecting passive interference and isolating signals from moving targets when processing signals from a target against a background of passive interference with a priori unknown correlation properties.

To solve the problem, a weighting coefficient calculator and a weighting block, connected to each other in a certain way, are introduced into the interference rejector-calculator, which contains the first, second and third delay blocks, a complex adder, a complex multiplier, a Doppler phase meter and a synchronization generator.

The essence of the invention as a technical solution is characterized by a set of essential features set out in the invention formula and ensuring the solution of the set problem by adaptive processing of incoming pulses.

The technical result of the invention consists in increasing the efficiency of rejecting passive interference with a priori unknown correlation properties and isolating signals from moving targets.

Fig. 1 shows a structural electrical circuit diagram of the noise rejector-computer; Fig. 2 - a delay unit; Fig. 3 - a complex adder; Fig. 4 - a complex multiplier; Fig. 5 - a weighting unit; Fig. 6 - a Doppler phase meter; Fig. 7 - a complex conjugation unit; Fig. 8 - an accumulator; Fig. 9 - a modulus calculator; Fig. 10 - a weighting coefficient calculator.

The noise rejector calculator (Fig. 1) contains delay blocks 1, 3, 4, a complex adder 2, a first complex multiplier 5, a Doppler phase meter 6, a synchronization generator 7, a weighting coefficient calculator 8 and a weighting block 9.

Delay blocks 1, 3, 4 (Fig. 2) contain two delay lines 10; complex adder 2 (Fig. 3) contains two adders 11; the first and second complex multipliers 5, 17 (Fig. 4) contain two channels (I, II), each of which contains first and second multipliers 12, 13 and adder 14; weighting block 9 (Fig. 5) contains two multipliers 15; Doppler phase meter 6 (Fig. 6) contains complex conjugation block 16, second complex multiplier 17 (Fig. 4), two accumulators 18, modulus calculation block 19 and two dividers 20; complex conjugation block 16 (Fig. 7) contains sign inverter 21; each accumulator 18 (Fig. 8) contains n delay elements 22 for interval t _d and n adders 23; the modulus calculation unit 19 (Fig. 9) contains two squarers 24, an adder 25 and a square root extraction unit 26; the weighting coefficient calculator 8 (Fig. 10) contains two squarers 27, an adder 28, an accumulator 29 (Fig. 8), a divider 30 and a sign inverter 31.

The noise rejector calculator can be implemented as follows.

The digital readings (x _kl , y _kl ) arriving at the input of the claimed device (Fig. 1) follow through a repetition period T and in each range resolution element (range ring) of each repetition period form a sequence of complex numbers

U _kl =x _kl +iy _kl =|U _kl |exp(ikϕ _l ),

where k is the number of the current period, l is the number of the current range ring, ϕ _l is the Doppler phase shift during the repetition period (Doppler phase), usually interference, due to its significant excess over the signal.

The digital readings in the claimed device (Fig. 1) are fed to the connected inputs of the second delay unit 3 for the interval τ, the second inputs of the Doppler phase meter 6 and the first inputs of the weighting coefficient calculator 8. The readings from the output of the first delay unit 1 for the interval T-τ are fed to the first inputs of the Doppler phase meter 6. The readings at the first and second inputs of the Doppler phase meter 6 are divided by the interval T.

The readings from the output of the second delay block 3 are fed to the first inputs of the complex adder 2 and to the inputs of the first delay block 1, from the output of which the readings are fed to the cascade-connected third delay block 4, the first complex multiplier 5, the weighting block 9 and the complex adder 2, the outputs of which are the outputs of the claimed device.

In the sign inverter 21 (Fig. 7) of the block 16 of the complex conjugation of the measuring device 6 (Fig. 6), the sign of the imaginary projections of the delayed readings is inverted. In the second complex multiplier 17, the multiplication of complex numbers occurs, which is realized by operations with the projections of these numbers in accordance with Fig. 4 and leads to the formation of quantities

In accumulators 18 (Fig. 6), with the help of delay elements 22 and adders 23 (Fig. 8), a sliding summation along the range in each repetition period is carried out of projections Re X _kl and ImX _kl from n+1 adjacent elements of the time strobe range resolution, except for the element with the number n/2+1, for which the output values of delay element 22 with the number n/2 are sent only to the subsequent delay element 22 (Fig. 8). As a result of accumulation, the values are formed

Where - an estimate of the Doppler phase shift of the interference over the repetition period T, averaged over n adjacent range resolution elements.

In block 19 for calculating the module (Fig. 9), the values are determined and then at the outputs of the dividers 20 (Fig. 6) - the values arriving at the second inputs of the first complex multiplier 5. Accumulation of n readings ensures highly accurate measurement of the value

Using squarers 27, adder 28, accumulator 29 and divider 30 (Fig. 10), the correlation coefficient of the interference is estimated based on the value |Y _k | coming from Doppler phase meter 6 and on the input readings U _kl according to which the weighting coefficient is located in the sign inverter 31

The first block 1 of delay for the interval T-τ together with the third block 4 of delay for the interval τ form the resulting delay for the interval T. As a result, the samples arrive at the inputs of the complex adder 2 synchronously. Taking into account the complex multiplication with the value and weighting of the delayed samples by the weighting coefficient a from the calculator 8 in the weighting block 9 as a result of in-phase summations in the complex adder 2 at its output the samples of the interference residues are calculated

Two-dimensional rotation of delayed samples in the first complex multiplier 5 by an angle provides the necessary phase synchronization of the summed readings to compensate for interference. Weighting by the weighting coefficient in block 9, the correlation properties of the interference are taken into account, increasing the efficiency of its rejection. Signal readings from a moving target are not suppressed due to the preservation of Doppler phase shifts.

The introduction of the second block 3 delays for the interval τ ensures that the estimates correspond the average element of the training sample, excluded in accumulators 18 (Fig. 8). The value of τ is determined by the expression

τ=t _in +nt _d /2,

where t _is the time of calculating the estimates n is the number of elements in the training sample, t _is the interval (period) of time sampling.

This eliminates the possibility of weakening or suppressing the signal due to its influence on the estimates used. In addition, errors are reduced due to the mismatch between the estimated and actual values of the Doppler phase and the interference correlation coefficient.

Synchronization of the interference rejector calculator is carried out by supplying a sequence of synchronizing pulses from the synchronizing generator 7 (Fig. 1) to all blocks of the claimed device.

The achieved technical result consists in increasing the efficiency of compensation for passive interference with a priori unknown correlation properties and the selection of signals from moving targets, which is achieved by adaptation to the interference parameters and a reduction in the discrepancy between the estimated and actual values of the interference parameters.

Thus, the interference rejector-computer allows increasing the efficiency of passive interference suppression and the identification of signals from moving targets against the background of passive interference with a priori unknown correlation properties.

Claims (1)

An interference rejector calculator comprising a first delay unit, a complex adder, a second delay unit, a third delay unit, a first complex multiplier, a Doppler phase meter and a synchroniser, wherein the inputs of the first delay unit are connected to the first inputs of the complex adder, the inputs of the second delay unit are connected to the second inputs of the Doppler phase meter, the outputs of the second delay unit are connected to the inputs of the first delay unit, the outputs of which are connected to the inputs of the third delay unit and the first inputs of the Doppler phase meter, the first outputs of which are connected to the second inputs of the first complex multiplier, the outputs of the third delay unit are connected to the first inputs of the first complex multiplier, the output of the synchroniser is connected to the synchroniser inputs of the first delay unit, the complex adder, the second delay unit, the third delay unit, the first complex multiplier and the Doppler phase meter, characterised in that a weighting coefficient calculator and a weighting unit are introduced, wherein the inputs of the second delay unit are connected to the first inputs of the weighting coefficient calculator, the second output of the Doppler phase meter is connected to the second input of the weighting coefficient calculator, the output of which is connected to the first input of the weighting unit, the outputs of the first complex multiplier are connected to the second inputs of the weighting unit, the outputs of which are connected to the second inputs of the complex adder, the output of the synchronization generator is connected to the synchronization inputs of the weighting coefficient calculator and the weighting unit, wherein the inputs of the interference rejector calculator are the inputs of the second delay unit, and the outputs are the outputs of the complex adder.

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