RU207018U1 - CALCULATOR FOR INTERFERENCE REDUCTION - Google Patents

Abstract

The utility model relates to the field of computer technology and can be used in automated systems for performing complex mathematical operations in order to isolate signals against the background of passive interference with unknown correlation properties. The achieved technical result is an increase in the efficiency of separation of signals from moving targets against the background of passive interference with a priori unknown correlation properties. This result is achieved by the fact that the calculator for rejection of interference contains a weight block, the first and second complex adders, the first, second, third and fourth delay blocks, a weight calculator and a sync generator, connected in a certain way and performing adaptive coherent processing of the original digital samples. 6 ill.

Description

The utility model relates to the field of computer technology and can be used in automated systems for performing complex mathematical operations in order to isolate signals against the background of passive interference with unknown correlation properties.

Known radar device for detecting a moving target [1], containing sequentially included delay blocks, a multiplier of complex numbers and a subtractor. However, this device has a low efficiency of separation of a moving target signal.

Another known device is a correlation auto-compensator [2], which contains a number of delay units, two multipliers, an adder and a unit for estimating the parameters of the correlated interference. The disadvantage of this device is the poor suppression of the edges of the extended noise due to the long time constant of the adaptive feedback loop.

The digital device closest to this utility model for suppressing passive interference [3], selected as a prototype, contains a weight unit, a complex adder and delay units. However, this device has a loss in noise rejection efficiency.

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

To solve this problem, the third and fourth delay blocks and the weight coefficient calculator are introduced into the calculator for interference rejection, which contains a weight block, a first delay block, first and second complex adders, a second delay block and a sync generator.

The essence of a utility model as a technical solution is characterized by a set of essential features set forth in the claims and providing a solution to the problem posed by optimal and consistent processing of incoming pulses.

The technical result of the utility model consists in increasing the efficiency of rejection of passive interference with a priori unknown correlation properties and the separation of signals from moving targets.

FIG. 1 shows a block diagram of a calculator for rejection of interference; in fig. 2 - weight block; in fig. 3 - delay block; in fig. 4 - complex adder; in fig. 5 - calculator of the weight coefficient; in fig. 6 - drive.

The calculator for rejection of interference (Fig. 1) contains a weighting unit 1, blocks 2, 4, 7, 8 delays, complex adders 3, 5, a sync generator 6 and a calculator 9 of the weight coefficient.

Weighting unit 1 (Fig. 2) contains two multipliers 10; blocks 2, 4, 7, 8 delay (Fig. 3) contain two lines 11 delay; complex adders 3, 5 (Fig. 4) contain two adders 12; the calculator 9 of the weighting factor (Fig. 5) contains four multipliers 13, an adder 14, two accumulators 15, a divider 16, a combining unit 17, a delay line 18, a square root extraction unit 19 and a memory unit 20; the accumulator 15 (Fig. 6) contains n elements 21 of the delay for the interval t _d and n adders 22.

The calculator for rejection of interference can be implemented as follows.

The initial sequence of coherent radio pulses, consisting of a signal from a moving target and passive interference significantly exceeding the signal, is represented by digital samples (x _jl , y _jl ) of input quadrature projections following a repetition period T in each (1st) range resolution element ( range ring) of each (j-th) repetition period.

Digital samples in the claimed device (Fig. 1) are fed to the connected inputs of the third delay unit 7 (Fig. 3) for the interval τ and the first inputs of the calculator 9 of the weighting coefficient (Fig. 5). The second inputs of the calculator 9 of the weighting coefficient receive the samples from the output of the first block 2 of the delay for the interval T - τ. The samples at the first and second inputs of the calculator 9 of the weight coefficient are divided into the interval T.

In the calculator 9, the multiplication of the delayed and non-delayed projections of the same name is carried out, followed by the summation of the obtained products in the adder 15. In the block 17 of combining, the sum of the squares of the projections is calculated. In the accumulators 15 (Fig. 6), using delay elements 21 and adders 22, a sliding along the range in each repetition period is performed summing incoming samples from n + 1 adjacent bins along the range of a temporary strobe, except for element n / 2 + 1, for whereby the output values of the delay element 21 with the number n / 2 are supplied only to the subsequent delay element 21. As a result of accumulation at the first input of the divider 16, the value is formed

where j is the number of the current period, l is the number of the current range ring, n is the volume of the training sample, determined by the number of samples from adjacent range resolution elements, with the exception of the average sample with the number l = n / 2 + 1.

In block 19 for extracting the square root, taking into account the previous operations in blocks 17, 15, 18 and 13, the value arriving at the second input of divider 16 is calculated

where

в видеAt the output of the divider 16, an estimate of the real part of the complex correlation coefficient of the interference is formed

as

- оценка коэффициента межпериодной корреляции,

- оценка доплеровского сдвига фазы за период повторения Т.where

- estimation of the coefficient of inter-period correlation,

- estimate of the Doppler phase shift for the repetition period T.

с хранимым в блоке 20 памяти множителем «- 2» образуется весовой коэффициентAs a result of multiplying the estimate

with the factor "- 2" stored in the memory unit 20, a weighting factor is formed

arriving at the second input of the weight unit 1 (Fig. 2).

The fourth block 8 of the delay for the interval τ together with the first block 2 of the delay for the interval T-τ form a resultant delay for the interval equal to the repetition period T. In the second block 4 of the delay, a delay for the interval T. arrive synchronously, forming at the output of the complex adder 5 counts of the residuals of the rejected interference in the form

where U _kl = x _kI + iy _kl .

учитывает коэффициент корреляции помехи

и ее доплеровский сдвиг фазы

что повышает эффективность режектирования помехи.Weight coefficient

takes into account the correlation coefficient of the interference

and its Doppler phase shift

which increases the efficiency of interference rejection.

для среднего элемента обучающей выборки, исключенного в накопителях 15 (фиг. 6). Величина τ определяется выражениемThe introduction of the third block 7 delaying the input samples for the interval τ provides the calculation of the estimates and the weighting factor

for the middle element of the training sample, excluded in the accumulators 15 (Fig. 6). The value of τ is determined by the expression

τ = t _in + nt _d / 2,

, n - количество элементов обучающей выборки, t_д - интервал (период) временно'й дискретизации.where t _in is the time of calculating the weight coefficient

, n is the number of elements of the training sample, t _d is the interval (period) of time sampling.

среднему элементу, исключенному из обучающей выборки. Тогда в случае сигнала, соизмеримого по величине с помехой, или разрывной помехи при режектировании отсчетов помехи с элемента разрешения, содержащего сигнал, исключается возможность ослабления или подавления сигнала за счет его влияния на используемые оценки. Кроме того, уменьшаются ошибки за счет рассогласования оцениваемых и действительных корреляционных свойств помехи.In this case, the correspondence of the weighting factor introduced into the weight block 1 is achieved

the middle element excluded from the training sample. Then, in the case of a signal comparable in magnitude with the interference, or discontinuous interference, when rejecting the interference samples from the permission element containing the signal, the possibility of attenuation or suppression of the signal is excluded due to its influence on the estimates used. In addition, errors are reduced due to the mismatch between the estimated and actual correlation properties of the interference.

и не влияющего на получаемую оценку

Adaptive processing is carried out for the average element of the training sample, excluded in the accumulators 15 (Fig. 6) in accordance with the algorithms for calculating the estimate

and does not affect the resulting estimate

Synchronization of the calculator for interference rejection is carried out by supplying all blocks of the claimed device with a sequence of synchronizing pulses from the sync generator 6 (Fig. 1). The repetition period of the synchronizing pulses is equal to the time sampling interval t _d , selected from the condition of the required range resolution.

The achieved technical result is as follows. The computed estimates of the parameters of the interference are used when weighing its samples corresponding to the average element of the training sample, which reduces the mismatch between the estimates obtained by averaging the samples of the training sample and the real properties of the noise. The exclusion of the middle element from the training sample makes it possible to exclude the possible influence of the signal on the efficiency of interference suppression.

Thus, the computer for rejection of interference can improve the efficiency of suppression of passive interference and the separation of signals from moving targets against the background of passive interference with a priori unknown correlation properties.

Bibliography

1. Patent No. 63-49193 (Japan), IPC G01S 13/52. Radar device for detecting a moving target / K.K. Toshiba. Publ. 03.10.1988. - Inventions of the countries of the world. - 1989. - Issue 109. - No. 15. - S. 52.

2. Radio-electronic systems: the basics of construction and theory. Handbook / Ya.D. Shirman, S.T. Baghdasaryan, A.S. Malyarenko, D.I. Lekhovitsky [and others]; under the editorship of Ya.D. Shirman. - 2nd ed., Rev. and add. - M .: Radiotekhnika, 2007; with. 439, fig. 25.22.

3.A.S. 743208 USSR, IPC G01S 7/36. Digital device for suppression of passive interference / D.I. Popov. - No. 2540079/09; app. 11/03/1977; publ. 06/25/1980, Bul. No. 23. - 4 p.

Claims (1)

A calculator for rejection of interference, containing a weight unit, a first delay unit, a first complex adder, a second delay unit, a second complex adder and a sync generator, while the inputs of the first delay unit are connected to the first inputs of the weight unit and the first inputs of the second complex adder, the outputs of the weight unit are connected with the first inputs of the first complex adder, the outputs of which are connected to the inputs of the second delay unit, the outputs of which are connected to the second inputs of the second complex adder, the sync generator output is connected to the sync inputs of the weight unit, the first delay unit, the first complex adder, the second delay unit and the second complex adder, characterized in that the third delay unit, the fourth delay unit and the calculator of the weight coefficient are introduced, while the inputs of the third delay unit are connected to the first inputs of the calculator of the weight coefficient, the outputs of the third delay unit are connected to the inputs of the first delay unit , the outputs of which are connected to the inputs of the fourth delay unit and the second inputs of the weighting factor calculator, the output of which is connected to the second input of the weighting unit, the outputs of the fourth delay unit are connected to the second inputs of the first complex adder, the sync generator output is connected to the sync inputs of the third delay unit, the fourth delay unit and the calculator of the weighting coefficient, and the inputs of the calculator for rejection of interference are the connected inputs of the third delay unit and the first inputs of the calculator of the weighting coefficient, and the outputs are the outputs of the second complex adder.

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