RU2617110C1 - Method to support group air targets of "aircraft with turbojet" class in radar location station at exposure of rate interference - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method consists in parallel maintenaning based on Kalman filtering the Doppler frequency samples (DF) caused by the signal reflections from the group airframes and the centroid DF samples caused by the signal reflections from the impeller blades of the first compressor stage of the low pressure group aircraft engines; identifying impacts or absence of the interference leading away by rate based on the calculation of the derivative difference modules between the DF estimates, caused by the signal reflections from the airframe of each group aircraft and the DF centroid, caused by the signal reflections from the impeller blades of the first compressor stage of the low pressure group aircraft engines; comparing the moduli of the DF derivative differences with a threshold; when they do not exceed the threshold that corresponds to the exposure absence of the interferences leading away by rate, the DF estimates are formed in the output, calculated in accordance with the Kalman filtering procedure on the basis of observations, otherwise a decision is made about the exposure of the interferences leading away by rate and in the outputs along with the DF estimates, which are not identified as the interferences leading away by rate, the DF estimates are formed calculated on the basis of the reciprocal movement model of the radar carrier and that group aircraft, the reflected signal from which has not yet been identified initially as the interferences leading away by rate.

EFFECT: increasedf reliability of Doppler frequency estimates due to convergence rate of radar location station carrier with each group aircraft upon exposure of rate interference.

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Description

The invention relates to the field of radar and can be used in a radar station (radar) to accompany a group of air targets (GVC) from the class "aircraft with turbojet engines (turbojet engines)" when exposed to speed-leading noise.

A known method of tracking a group of air targets, which consists in tracking its centroid (average kinematic behavior of the group) and side trajectories, recognition based on a comparison of the state variables of the central and side trajectories of the separating targets from the group [1].

The disadvantage of this method of tracking a group of air targets is the low reliability of the estimates of the Doppler frequencies due to the speed of approach of the radar carrier with each aircraft from the group when exposed to speed-leading noise.

There is a method of tracking a group of air targets from the class "aircraft with turbojet engines", which consists in the fact that the signal reflected from it at an intermediate frequency from the output of the radar receiver is subjected to narrow-band Doppler filtering based on the fast Fourier transform (FFT) and is converted to amplitude -frequency spectrum, the components of which are caused by signal reflections from the gliders of the group’s airplanes and the rotating blades of the impeller of the low pressure compressor (LPC) of their power plants , the Doppler frequency reference is determined, which corresponds to the maximum amplitude of the spectral component of the signal spectrum, which is caused by its reflection from the glider of one of the aircraft from their group, left and right in the frequency band ± ΔF, where ΔF is the a priori specified Doppler frequency band occupied by the spectral components due to reflections of the signal from the gliders of the group’s planes, relative to the frequency of the spectral component of the signal spectrum having the maximum amplitude, the local maximum frequencies are determined in the signal spectrum and their number that exceeded the set threshold, according to the detected samples of the Doppler frequencies of local maxima located in the frequency band ± ΔF relative to the spectral component having the maximum amplitude, the sample of the Doppler frequency of the centroid is calculated as the average value of the samples of the Doppler frequencies of local maxima, which arrives at the input of the optimal centroid tracking filter of a group air target operating in accordance with the optimal multidimensional linear th discrete Kalman filter described expressions

Where

- номер такта работы фильтра;

- filter cycle number;

K is the total number of clock cycles of the filter;

P ^- (k + 1) and P (k + 1) are the covariance matrices of extrapolation and filtering errors, respectively;

Ф (k) - transition state matrix;

Q (k + 1) and R (k + 1) are the covariance matrices of excitation and observation noise, respectively;

S (k + 1) is the matrix of weights;

I is the identity matrix;

и

- вектор текущих и экстраполированных оценок доплеровской частоты, обусловленной скоростью сближения центроида групповой воздушной цели с носителем станции ее сопровождения;

and

- a vector of current and extrapolated estimates of the Doppler frequency due to the speed of approach of the centroid of the group air target with the carrier of its tracking station;

H (k) is the observation matrix;

Y (k) is the observation vector of samples of Doppler frequencies;

Z (k + 1) - matrix of measurement residuals;

Ψ (k + 1) is the matrix of a priori filtering errors;

"-1" - inverse matrix calculation operation;

; J - количество самолетов в группе, самолета группы и работающего аналогично, как и оптимальный фильтр сопровождения центроида групповой воздушной цели, в соответствии с процедурой (1)-(6), при этом размерность матриц, входящих в процедуру (1)-(6), определяется количеством локальных максимумов спектральных составляющих сигнала, находящихся в полосе частот ±ΔF относительно спектральной составляющей с максимальной амплитудой, соответствующей отражению сигнала от планера одного из самолетов группы, на каждом k-ом такте работы обоих оптимальных фильтров сопровождения определяются оценки разности

между оцененными значениями доплеровских частот, соответствующих центроиду групповой воздушной цели

и отражениям сигнала от лопаток рабочего колеса первой ступени

компрессора низкого давления двигателя каждого j-го самолета группы, которые соответствуют только одному из распознаваемых типу воздушной цели из класса «самолеты с турбореактивными двигателями», при этом весь диапазон возможных значений оценок разностей

априорно разбивается на Q неперекрывающихся друг с другом поддиапазонов, нижняя F_Hq и верхняя F_Bq границы каждого q-го поддиапазона,

, соответствующего i-му типу цели, где

; I - максимальное количество распознаваемых типов воздушных целей из класса «самолеты с турбореактивными двигателями», определяются выражениями"t" is the matrix transposition operation, the samples of the Doppler frequencies of local maxima having the largest amplitudes are determined, the number of which is equal to the number of local maxima located in the Doppler frequency band ± ΔF relative to the spectral component with the maximum amplitude corresponding to the signal reflection from the glider of one of the group’s planes, and located on the right at frequencies exceeding the ΔF value, relative to the frequency of the spectral component having the maximum amplitude, which arrive at input of the optimal filter support first compressor constituting the signal spectrum caused by its reflection from the impeller blades of the first stage motor CPV each j-th, where

; J is the number of planes in a group, a plane of a group and operating in the same way as the optimal filter for tracking the centroid of a group air target, in accordance with procedure (1) - (6), while the dimension of the matrices included in procedure (1) - (6) , is determined by the number of local maxima of the spectral components of the signal in the frequency band ± ΔF relative to the spectral component with a maximum amplitude corresponding to the reflection of the signal from the glider of one of the group’s planes, at each k-th operation cycle of both optimal ltrov accompaniment determined estimate the difference

between estimated Doppler frequencies corresponding to the centroid of a group air target

and signal reflections from the blades of the impeller of the first stage

low-pressure compressor of the engine of each j-th aircraft of the group that correspond to only one of the recognizable type of air targets from the class "aircraft with turbojet engines", while the entire range of possible values of the differences

a priori is divided into Q non-overlapping subbands, the lower F _Hq and the upper F _Bq boundaries of each qth subband,

corresponding to the i-th type of target, where

; I - the maximum number of recognizable types of air targets from the class "aircraft with turbojet engines", are determined by the expressions

Where

F _Pi is the maximum rotational speed of the low-pressure rotor of the power plant of the i-type aircraft;

n ₁ and n ₂ - respectively, the minimum and maximum values of the relative speed of rotation of the rotor of the power plant, the same for all types of aircraft of the group;

в каждый из априорно сформированный q-й поддиапазон, определяются номера i-х поддиапазонов, для которых величины вероятностей P_qj максимальны, максимальные значения величин P_qj max сравниваются с пороговым значением вероятности распознавания типа каждого самолета группы P_пор, при P_{qj max}≥Р_пор принимается решение о том, что j-й самолет в группе имеет i-й тип из класса «самолеты с турбореактивными двигателями» с вероятностью P_{qj max}, не ниже заданной, в противном случае принимается решение о невозможности распознать тип самолета в группе с заданной вероятностью, количество величин разностей

, попавших в q-й поддиапазон с вероятностями P_{qj max}, определяет количество самолетов i-го типа в группе [2].N _li is the number of blades of the impeller of the first stage of the _{low pressure switch} , calculated for K clock cycles of both optimal filters of probability P _qj

into each of the a priori generated qth subbands, the numbers of the i-subbands are determined for which the probability values P _{qj are} maximum, the maximum values of the values P _qj max are compared with the threshold value of the type recognition probability of each aircraft of the group P _then , at P _{qj max} ≥Р _then a decision is made that the j-th aircraft in the group is the i-th type of class "aircraft with turbojet engines" with a probability of P _{qj max,} not lower than a given, otherwise the decision on the impossibility to recognize the type of aircraft in the group with the task th probability, the number of values of the differences

that fall into the qth subrange with probabilities P _{qj max} determines the number of i-type aircraft in the group [2].

, самолетом группы при воздействии уводящих по скорости помех.The disadvantage of this method of tracking a group of air targets is the low reliability of the estimates of the Doppler frequencies due to the speed of approach of the radar carrier with each jth,

, by an airplane of a group under the influence of noise leading away in speed.

The purpose of the invention is to increase the reliability of estimates of Doppler frequencies due to the speed of approach of the radar carrier with each aircraft of the group under the influence of noise that leads away in speed.

, планерной составляющей спектра сигнала, обусловленной скоростью сближения каждого j-го,

, самолета группы с носителем РЛС, при этом, размерность матриц, входящих в процедуру (1)-(6), определяется количеством локальных максимумов спектральных составляющих сигнала, находящихся в полосе частот ±ΔF относительно спектральной составляющей с максимальной амплитудой, соответствующей отражению сигнала от планера одного из самолетов группы, по выявленным отсчетам доплеровских частот локальных максимумов, находящихся справа на частотах, превышающих значение ΔF и соответствующих отражениями сигнала от лопаток рабочего колеса первых ступеней КНД двигателей самолетов группы, вычисляется отсчет доплеровской частоты центроида, как среднее значение отсчетов доплеровских частот локальных максимумов, который поступает на вход оптимального фильтра сопровождения центроида отсчетов доплеровских частот, обусловленных отражением сигнала от лопаток рабочего колеса первых ступеней КНД двигателей самолетов группы, работающего аналогично, как и оптимальный фильтр сопровождения планерных составляющих спектра сигнала в соответствии с процедурой (1)-(6), на каждом k-ом такте работы обоих оптимальных фильтров сопровождения вычисляются оценки разностей

между оцененными значениями доплеровских частот, соответствующих центроиду доплеровской частоты

, обусловленной отражениями сигнала от лопаток рабочего колеса первых ступеней КНД двигателей самолетов группы, и отражениям сигнала от планера

каждого j-го самолета группы,

, вычисляются модули производных оценок разностей

между оцененными значениями доплеровских частот

, обусловленными отражениями сигнала от планера каждого j-го самолета группы и центроидом доплеровской частоты

), обусловленной отражениями сигнала от лопаток рабочего колеса первых ступеней КНД двигателей самолетов группы, которые сравниваются с пороговым значением ε, близким к нулю, при выполнении условия

для всех j-ых,

, оценок планерных составляющих спектра сигнал, что соответствует отсутствию воздействия уводящих по скорости помех, в качестве выходной информации используются все оценки

,

, доплеровских частот, вычисляемые в соответствии с процедурой (1)-(6) на основе наблюдения Y(k), при не выполнении условия

для всех

, что соответствует воздействию уводящих по скорости помех, наряду с оценками доплеровских частот

, где

; M - количество оценок доплеровских частот, которые не идентифицированы, как уводящие по скорости помехи, формируются оценки доплеровских частот

, где

; N - количество оценок доплеровских частот, которые идентифицированы, как уводящие по скорости помехи; J=M+N, вычисляемые в соответствии с процедуройThis goal is achieved by the fact that in the method of tracking in a radar a group air target from the class “turbojet aircraft”, consisting in the fact that the signal reflected from the MCC at the intermediate frequency from the output of the radar receiver is subjected to narrow-band Doppler filtering based on the FFT procedure and is converted in the amplitude-frequency spectrum, the components of which are due to reflections of the signal from the gliders of the group’s aircraft and the rotating blades of the KND impeller of their power plants, the Doppler count is determined The frequency corresponding to the maximum amplitude of the spectral component of the signal spectrum, which is caused by its reflection from the glider of one of the group’s planes, is determined on the left and right in the frequency band ± ΔF, where ΔF is the a priori specified Doppler frequency band occupied by the spectral components due to the signal reflections from the gliders aircraft of the group, relative to the frequency of the spectral component of the signal spectrum having the maximum amplitude, samples of the Doppler frequencies of the local maxima of the sig spectrum the number of local maxima located in the Doppler frequency band ± ΔF relative to the spectral component with the maximum amplitude corresponding to the signal reflection from the glider of one of the aircraft group, and located on the right at frequencies exceeding the ΔF value, relative to the frequency of the spectral component having the maximum amplitude , which are caused by signal reflections from the blades of the impeller of the first stages of the low-pressure compressor of the group's aircraft engines, the procedure of optimal multidimensional linear discrete Kalman filtering is additionally calculated in accordance with expressions (1) - (6) accompanied by the Doppler frequency of each jth,

, the glider component of the signal spectrum, due to the approach speed of each j-th,

, an aircraft of a group with a radar carrier, in this case, the dimension of the matrices included in procedure (1) - (6) is determined by the number of local maxima of the spectral components of the signal in the frequency band ± ΔF relative to the spectral component with a maximum amplitude corresponding to the reflection of the signal from the glider one of the aircraft of the group, according to the detected samples of the Doppler frequencies of local maxima located on the right at frequencies exceeding the ΔF value and corresponding to the signal reflections from the impeller blades of the first If the efficiency of the group aircraft engines is low, the Doppler frequency of the centroid is calculated as the average value of the Doppler frequencies of the local maxima, which is fed to the input of the optimal filter for tracking the centroid of the Doppler frequencies, due to the reflection of the signal from the impeller blades of the first stages of the KND of the engines of the group’s aircraft, which works similarly, as well as the optimal filter for tracking the glider components of the signal spectrum in accordance with the procedure (1) - (6), at each k-th step of work both optimal tracking filters calculated difference evaluation

between the estimated Doppler frequencies corresponding to the centroid of the Doppler frequency

due to reflections of the signal from the blades of the impeller of the first stages of the CPV of the aircraft engines of the group, and reflections of the signal from the glider

every j-th plane of the group,

, the modules of the derived estimates of the differences are calculated

between estimated Doppler frequencies

due to the reflections of the signal from the glider of each j-th group aircraft and the centroid of the Doppler frequency

), due to the reflection of the signal from the impeller blades of the first stages of the low-pressure rotational engines of the group aircraft engines, which are compared with a threshold value ε close to zero, when the condition

for all the jth,

, estimates of the glider components of the spectrum of the signal, which corresponds to the absence of the effect of noise leading away in speed, all estimates are used as output information

,

Doppler frequencies calculated in accordance with procedure (1) - (6) based on the observation of Y (k), if the condition

for all

, which corresponds to the effect of noise leading away in speed, along with estimates of Doppler frequencies

where

; M is the number of estimates of Doppler frequencies that are not identified as noise that leads away in speed; estimates of Doppler frequencies are formed

where

; N is the number of estimates of Doppler frequencies that are identified as speed-leading interference; J = M + N calculated according to the procedure

Where

- переходная матрица состояния, численные значения элементов которой определяются на основе корреляционного анализа текущих значений оценок доплеровских частот

,

, полученных до момента времени, когда выполнялось условие

и идентифицированные затем, как уводящие по скорости помехи;

- a transition state matrix, the numerical values of the elements of which are determined on the basis of a correlation analysis of the current values of the estimates of Doppler frequencies

,

received until the moment when the condition was met

and then identified as speed-leading interference;

- оцененный вектор состояния, содержащий оценку доплеровской частоты

,

, полученную после ее идентификации, как уводящей по скорости помехи,

- estimated state vector containing an estimate of the Doppler frequency

,

obtained after its identification as leading in the speed of interference,

, учитывающей модель взаимного перемещения носителя РЛС и того самолета группы, отраженный от которого сигнал изначально еще не был идентифицирован, как уводящая по скорости помеха.only based on a transition state matrix

taking into account the model of mutual movement of the radar carrier and that group aircraft, the reflected signal from which the signal was not originally identified as speed-leading noise.

New features that have significant differences are.

. При их не превышении установленного порога ε, близкого к нулю

для всех оценок доплеровских частот

, принимается решение об отсутствии воздействия уводящих по скорости помех, в противном случае, при выполнении условий

либо для всех, либо части оценок доплеровских частот

из их совокупности, принимается соответственно решение о том, что либо все, либо часть доплеровских частот из их совокупности, обусловленные скоростями сближения носителя РЛС с каждым j-м,

, самолетом группы идентифицируются, как уводящие по скорости помехи.1. Identification of the absence or effect of noise leading away in speed based on the analysis of a set of modules of derivative estimates of differences of quantities

. If they do not exceed the established threshold ε close to zero

for all estimates of Doppler frequencies

, a decision is made about the absence of impact of noise that leads away in speed, otherwise, under the conditions

either for all or part of the estimates of Doppler frequencies

from their combination, respectively, a decision is made that either all or part of the Doppler frequencies from their combination is determined by the approach speeds of the radar carrier with each jth,

, by plane, groups are identified as speed-leading interference.

,

, обусловленных скоростью сближения носителя РЛС с каждым самолетом группы в соответствии с процедурой (1)-(6) при полном отсутствии уводящих по скорости помех, когда условия

выполняются для всех оценок доплеровских частот

или оценок

,

при идентификации M оценок без воздействия и

,

при идентификации N оценок при воздействии уводящих по скорости помех, когда условия

соответственно выполняются только для М и не выполняются для N оценок доплеровских частот.2. The formation of reliable estimates of Doppler frequencies

,

due to the speed of approach of the radar carrier with each aircraft of the group in accordance with the procedure (1) - (6) in the complete absence of noise that leads away in speed, when the conditions

performed for all estimates of Doppler frequencies

or ratings

,

in identifying M ratings without impact and

,

when identifying N estimates when exposed to speed-leading noise when conditions

accordingly, they are performed only for M and are not performed for N estimates of Doppler frequencies.

These signs have significant differences, as in the known methods are not found.

The use of new features will allow us to identify the impact or absence of speed-guiding interference when tracking a group of air targets in the radar and, depending on the identification result, generate reliable estimates of the Doppler frequencies due to the speed of approach of the radar carrier with each aircraft of the group when exposed to speed-guiding noise.

Figure 1 shows a block diagram explaining the proposed method of tracking in a radar a group of airborne targets from the class “aircraft with turbojet engines” when exposed to speed-guiding interference; in Figure 2 (a, b, c, d, e) - diagrams explaining the proposed method is an example of tracking a group of air targets, consisting of two aircraft, and the impact of one noise that leads away in speed.

The method of tracking in a radar a group of air targets from the class "aircraft with turbojet engines" when exposed to speed-leading noise is as follows.

The input of the FFT block 1 (Fig. 1) at an intermediate frequency from the output of the radar receiver receives a signal S (t) (Fig. 2a), reflected from the MCC, which is subjected to narrow-band Doppler filtering based on the FFT procedure and is converted into the amplitude-frequency spectrum S (f ) (Figure 2b), the components of which are caused by signal reflections from the gliders of the group’s airplanes and rotating blades of the KND impeller of their power plants.

In shaper 2 (Figure 1), samples of the Doppler frequencies of the glider components of the signal spectrum, firstly, a sample of the Doppler frequency corresponding to the maximum amplitude of the spectral component of the signal spectrum, which is caused by its reflection from the glider of one of the aircraft from their group, is determined (Figure 2b, spectral component No. 2), secondly, the frequencies of local maxima are determined on the left and right in the frequency band ± ΔF relative to the frequency of the spectral component of the signal spectrum having the maximum amplitude pektra signal and number (Figure 2b, N = 2 _lm) that exceeded the threshold.

In shaper 3 (Figure 1) of the Doppler frequency count of the centroid of the first compressor components of the signal spectrum, firstly, the Doppler frequencies of local maxima having the largest amplitudes are determined, the number of which is equal to the number of local maxima located in the Doppler frequency band ± ΔF relative to the spectral component with the maximum amplitude corresponding to the reflection of the signal from the glider of one of the planes of the group, and located on the right at frequencies exceeding the ΔF value, relative about the frequency of the spectral component having a maximum amplitude, which are caused by signal reflections from the blades of the impellers of the first stages of the KND of the group’s planes (Figure 2b, local maxima No. 1 and 2, are on the right outside the frequency band ± ΔF), and secondly, according to the detected Doppler counts frequencies of local maxima located on the right at frequencies exceeding the ΔF value and corresponding to the signal reflections from the blades of the impellers of the first stages of the low-pressure CPV of the group's aircraft engines, the Doppler frequency count ntroida as the mean value of samples of Doppler frequencies of local maxima.

As a result, at the output of the shaper 2 Doppler samples (Figure 1), an observation vector Y (k) of samples of Doppler frequencies, caused by signal reflections from the gliders of the group’s planes, is fed to the input of the optimal filter 4 for tracking a group of air targets operating in accordance with the multidimensional linear discrete Kalman filtering (1) - (6), and at the output of the shaper 3 samples of the Doppler frequency of the centroid of the first compressor components of the signal spectrum is the observation vector Y _c (k) the centroid of the Doppler frequency, which is fed to the input of the optimal filter 5 for tracking the centroid of the first compressor components of the signal spectrum, which works similarly to the optimal filter 4, in accordance with procedure (1) - (6). Moreover, the dimension of the matrices included in procedure (1) - (6) for optimal filter 4 is determined by the number of local maxima N _{lm of the} spectral components of the signal in the frequency band ± ΔF.

между оцененными значениями доплеровских частот, соответствующих центроиду доплеровской частоты

, обусловленной отражениями сигнала от лопаток рабочего колеса первых ступеней КНД двигателей самолетов группы, и отражениям сигнала от планера

каждого j-го самолета группы,

. Причем, данные оценки разностей

при отсутствии воздействия уводящих по скорости помех являются постоянными величинами для каждого типа самолета в группе из класса «самолет с турбореактивным двигателем».At each k-th operation cycle of both optimal tracking filters 4 and 5 in the subtraction unit 6, consisting of separate subtraction devices, the difference estimates are calculated

between the estimated Doppler frequencies corresponding to the centroid of the Doppler frequency

due to reflections of the signal from the blades of the impeller of the first stages of the CPV of the aircraft engines of the group, and reflections of the signal from the glider

every j-th plane of the group,

. Moreover, these estimates of differences

in the absence of exposure to speed-leading noise, they are constant values for each type of aircraft in the group of the class “aircraft with a turbojet engine”.

между оцененными значениями доплеровских частот

, обусловленными отражениями сигнала от планера каждого j-го самолета группы и центроидом доплеровской частоты

, которые поступают на соответствующие пороговые устройства блока 8 порогов, куда также, на все пороговые устройства поступает пороговое значение ε, близкое по величине к нулю.In block 7 differentiation, consisting of their individual devices of differentiation, the modules are calculated derived estimates of differences

between estimated Doppler frequencies

due to the reflections of the signal from the glider of each j-th group aircraft and the centroid of the Doppler frequency

which enter the corresponding threshold devices of the threshold unit 8, where also, all threshold devices receive a threshold value ε close to zero in magnitude.

для всех j-ых,

, оценок планерных составляющих спектра сигнал, что соответствует отсутствию воздействия уводящих по скорости помех, (поскольку (рисунки 2 в, г, д - временные участки [t₀;t₁] и [t₂;t₃]) величины

- постоянны и их производные равны нулю), на выходе блока 8 порогов формируется цифровой код (на рисунке 1-«p^(j=m)/з^(j=m)»), который является разрешающим (индекс «p^(j-m)») кодом для коммутаторов 9 и 10, запрещающим (индекс «з^(j=m)») кодом для оперативного запоминающего устройства (ОЗУ) 11 и вычислителя 12 параметров автокорреляционных функций (АКФ) оценок доплеровских частот планерных составляющих спектра сигнала. В этом случае в качестве выходной информации используются все оценки

,

, J=M, доплеровских частот, вычисляемые в соответствии с процедурой (1)-(6) на основе наблюдения Y(k), которые также через первый коммутатор 9 (на его втором входе присутствует разрешающий код «p^(j=m)»), поступают на вход ОЗУ 11 (построен на основе сдвиговых регистров), где осуществляется хранение текущих оценок

доплеровских частот при отсутствии воздействия уводящей по скорости помехи. Поскольку для ОЗУ 11 в данном случае будет сформирован запрещающий код «з^j=m)» на выходе блока 8 порогов, то хранящиеся в нем текущие оценки

далее не поступают на вход вычислителя 12 параметров АКФ, на втором входе которого также будет присутствовать запрещающий код «з^(j=m)» с выхода блока 8 порогов.When the condition is met

for all the jth,

, estimates of the glider components of the spectrum of the signal, which corresponds to the absence of the effect of noise leading away in speed, (since (Figures 2c, d, d are the temporary sections [t ₀ ; t ₁ ] and [t ₂ ; t ₃ ])

are constant and their derivatives are equal to zero), at the output of block 8 of thresholds, a digital code is generated (in figure 1 - “p ^{(j = m)} / s ^{(j = m)} ”), which is permissive (index “p ^(jm) ” ) code for the switches 9 and 10, prohibiting (index "h ^{(j = m)} ") code for random access memory (RAM) 11 and calculator 12 parameters of the autocorrelation functions (ACF) estimates of the Doppler frequencies of the glider components of the signal spectrum. In this case, all estimates are used as output information.

,

, J = M, Doppler frequencies calculated in accordance with procedure (1) - (6) based on the observation of Y (k), which are also through the first switch 9 (at its second input there is an enable code “p ^{(j = m)} ” ), go to the input of RAM 11 (built on the basis of shift registers), where the current ratings are stored

Doppler frequencies in the absence of exposure to speed-leading interference. Since for the RAM 11 in this case a prohibiting code “z ^{j = m)} ” will be generated at the output of the threshold block 8, the current estimates stored in it

then 12 ACF parameters do not arrive at the input of the calculator, at the second input of which there will also be a prohibiting code “h ^{(j = m)} ” from the output of the 8 threshold block.

для всех или части оценок доплеровских частот, что соответствует воздействию уводящих по скорости помех, поскольку (рисунки 2 в, г, д - временной участок [t₁;t₂]) величины

в этом случае будут постоянными, если изменение уводящей по скорости помехи осуществляется по линейному закону или изменяться по другому закону в соответствии с законом изменения уводящей по скорости помехи. В обоих случаях значения величин

будут существенно отличаться от нуля, и на выходе блока 8 порогов сформируется результирующий код, который будет состоять из двух частей - запрещающего кода «з⁽ⁿ⁾» и разрешающего кода «р^(m)» для коммутаторов 9 и 10, из разрешающего кода «p⁽ⁿ⁾» и запрещающего кода «з⁽ⁿ⁾» для ОЗУ 11 и вычислителя 12 параметров АКФ.If the condition is not met

for all or part of the estimates of Doppler frequencies, which corresponds to the effect of noise leading in speed, since (Figs. 2 c, d, d are the time section [t ₁ ; t ₂ ])

in this case, they will be constant if the change in the noise that leads away in speed is carried out according to the linear law or if it changes in another law in accordance with the law of the change in the noise that takes away in the speed. In both cases, the values

will be significantly different from zero, and at the output of block 8 of thresholds, a resultant code will be formed, which will consist of two parts - the prohibit code "h ⁽ⁿ⁾ " and the enable code "p ^(m) " for switches 9 and 10, from the enable code " p ⁽ⁿ⁾ ”and the prohibition code“ h ⁽ⁿ⁾ ”for RAM 11 and the calculator 12 of the ACF parameters.

,

, которые не были идентифицированы, как уводящие по скорости помехи (разрешающий код «р^(m)» на входе первого коммутатора 9) и прекращается поступление текущих оценок

,

, которые были идентифицированы, как уводящие по скорости помехи (запрещающий код «з⁽ⁿ⁾» на входе первого коммутатора 9). Только те оценки доплеровских частот

, которые изначально не были (рисунки 2 в, г, д - временные участки [t₀;t₁] и [t₂;t₃]), а затем были идентифицированы (временной участок [t₁;t₂]), как уводящие по скорости помехи, с выхода ОЗУ 11 (на его входе присутствует разрешающая «p⁽ⁿ⁾» и запрещающая «з^(m)» составляющие кода) поступают на вход вычислителя 12 параметров АКФ (на его входе присутствует также разрешающая «p⁽ⁿ⁾» и запрещающая «з^(m)» составляющие кода), в котором вычисляются АКФ оценок

доплеровских частот в дискретном времени (которые были получены до их идентификации, как уводящие по скорости помехи) в соответствии с выражением [3]As a result, estimates of Doppler frequencies continue to be received at the input of RAM 11

,

that have not been identified as speed-guiding interference (enable code "p ^(m) " at the input of the first switch 9) and the flow of current estimates ceases

,

, which were identified as speed-guiding interference (prohibiting code “h ⁽ⁿ⁾ ” at the input of the first switch 9). Only those estimates of Doppler frequencies

that were not originally (Figures 2 c, d, e - temporary sections [t ₀ ; t ₁ ] and [t ₂ ; t ₃ ]), and then were identified (temporary section [t ₁ ; t ₂ ]), as noise away from the speed of the RAM 11 (at its input there is a resolving “p ⁽ⁿ⁾ ” and prohibiting “h ^(m) ” components of the code) are fed to the input of the calculator 12 ACF parameters (at its input there is also a resolving “p ^{(n )} ”And prohibiting“ h ^(m) ”code components), in which the ACF estimates are calculated

Doppler frequencies in discrete time (which were obtained prior to their identification as speed-leading noise) in accordance with the expression [3]

Where

Δt is the sampling interval;

z = 1, 2, ..., p.

m _F is the trend (the expected value in discrete time) of the Doppler frequency estimate.

доплеровской частоты, аппроксимируется спадающей по экспоненциальному закону косинусоидальной зависимостью вида [3]The autocorrelation function calculated in accordance with expression 9 for each estimate

Doppler frequency is approximated by an exponentially decreasing cosine dependence of the form [3]

Where

σ _v , τ _v, and f _v are the standard deviation, correlation time, and natural frequency, respectively, which are ACF parameters.

,

, доплеровской частоты, которая была получена до ее идентификации, как уводящей по скорости помехи, поступают на вход вычислителя 13 оценок

доплеровских частот, которые вычисляются в соответствии с выражением (9).Numerical values of the ACF parameters (σ _v , τ _v , f _v ) of each estimate

,

, the Doppler frequency, which was obtained before its identification as a noise-guiding one, is fed to the input of the computer 13 estimates

Doppler frequencies, which are calculated in accordance with expression (9).

,

, доплеровских частот до их идентификации, как уводящих по скорости помех, поступившие и хранящиеся в ОЗУ 11.Moreover, in the calculator 13, firstly, at the first step of the recursive procedure for calculating the estimates, the final values of the estimates are accepted

,

, Doppler frequencies until they are identified as noise-guiding, received and stored in RAM 11.

,

, размерностью 3×3, будут иметь следующие, отличные от нуля, элементы: ϕ₁₁=1; ϕ₁₂=Δt; ϕ₂₁=-βΔt; ϕ₂₂=1-αΔt; ϕ₃₃=1+Δt, которые соответствуют динамической модели радиальных составляющих фазовых координат полета каждого самолета группы относительно носителя РЛС, описываемой следующей системой дифференциальных уравнений в непрерывном времени [3]Secondly, matrices

,

, dimension 3 × 3, will have the following non-zero elements: ϕ ₁₁ = 1; ϕ ₁₂ = Δt; ϕ ₂₁ = -βΔt; ϕ ₂₂ = 1-αΔt; ϕ ₃₃ = 1 + Δt, which correspond to the dynamic model of the radial components of the phase coordinates of the flight of each group aircraft relative to the radar carrier, described by the following system of differential equations in continuous time [3]

Where

β = (2πf _v ) ² is the square of the frequency f _{v of the} natural vibrations of the ACF, which are caused by the high-speed fluctuations of the flight of each aircraft of the group and the radar carrier;

- дисперсия флюктуаций радиального ускорения каждого самолета группы относительно носителя РЛС;

- dispersion of fluctuations in the radial acceleration of each group aircraft relative to the radar carrier;

n (t) - forming a white Gaussian noise with zero mean values and unit intensities;

V _o is a constant component of the flight speed of each group aircraft;

- величина, обратная времени корреляции и характеризующая расширение спектра сигнала.

- the reciprocal of the correlation time and characterizing the expansion of the signal spectrum.

будет иметь размерность 3×1 и вид |ΔV, a, V₀|^T.According to model (12), the matrix of estimates

will have a dimension of 3 × 1 and the form | ΔV, a, V ₀ | ^T.

The observation matrix H (k + 1), dimension 1 × 3, will have the following non-zero elements: h ₁₁ = h ₁₃ = 1.

,

, доплеровских частот, которые поступают на вход второго коммутатора 10. В результате на его выходе будут сформированы оценки доплеровских частот

,

на основе наблюдения Y(k) в соответствии с процедурой фильтрации (1)-(6) и которые не идентифицированы, как уводящие по скорости помехи (рисунок 2в, временные участки [t₀;t₁] и [t₂;t₃]), а также оценки доплеровских частот

,

, только на основе переходных матриц,

,

, которые были идентифицированы, как уводящие по скорости помехи (рисунок 2в, временной участок [t₁;t₂]). При этом общее количество оценок будет равно J=M+N.As a result, when exposed to speed-guiding interference (Figure 2c, time section [t ₁ , t ₂ ]), evaluations will be generated at the output of calculator 13

,

, Doppler frequencies that are fed to the input of the second switch 10. As a result, estimates of Doppler frequencies will be generated at its output

,

based on the observation of Y (k) in accordance with the filtering procedure (1) - (6) and which are not identified as speed-leading disturbances (Figure 2c, temporary sections [t ₀ ; t ₁ ] and [t ₂ ; t ₃ ] ), as well as estimates of Doppler frequencies

,

, based only on transition matrices,

,

that have been identified as speed-guiding interference (Figure 2c, time section [t ₁ ; t ₂ ]). Moreover, the total number of ratings will be equal to J = M + N.

To assess the performance of the proposed method, its simulation was carried out. At the same time, radar signals were used, reflected from a group of 4 aircraft from the class “aircraft with turbojet engines”, which during flight experimental studies were recorded at an intermediate frequency from the output of the linear part of the receiver of the onboard radar with a phased antenna array built by the pulse-Doppler principle of signal processing in the centimeter wavelength range.

In the narrow-band spectral analysis of recorded real radar signals in the FFT procedure, the equivalent bandwidth of its one bin was taken to be 10 Hz.

The numerical values of the parameters of dynamic models included in the optimal filters 4 and 5, as well as in the computer 13, were taken from the example given in [3].

In the time interval (Fig. 2c) [t ₁ ; t ₂ ], a Doppler frequency-leading noise was simulated at a speed of 575 Hz / s.

The threshold value for all threshold devices of the threshold block 8 was ε = 0.01.

As a result of simulation using real signals, the following generalized characteristics were obtained with a signal-to-noise ratio of 14-24 dB:

standard error of the estimate of the Doppler frequency:

without impact of speed-leading (Doppler frequency)

interference - 0.9-2.2 Hz;

when exposed to speed-leading (Doppler frequency)

interference - 1.6-3.7 Hz,

which is acceptable in practice.

Thus, the application of the present invention will allow us to identify the impact or absence of speed-leading interference when tracking targets in the radar and, depending on the identification result, generate reliable estimates of Doppler frequencies due to the speed of approach of each aircraft of the group with the carrier of the radar.

Information sources

1. Farina A., Studer F. Digital processing of radar information. Tracking goals. / Per. from English - M .: Radio and communications, 1993, p. 246-248 (analogue).

2. A method of tracking a group of air targets from the class "aircraft with turbojet engines". Patent for invention No. 2456633, 2011 (prototype).

3. Bogdanov A.V., Vasiliev O.V., Golubenko V.A., Manyashin S.M., Filonov A.A. A technique for constructing dynamic models of radial speeds and accelerations of a pair of air targets flying in a closed combat order // Theory and Control Systems, 2007 - No. 4 (pages 139, 142, 145, 146 - formulas (2.1), (2.2), (3.2) - (3.5), (5.3), (5.4) and (5.11), an example of subsections 2, 3, 4, 7).

Claims (28)

A method of escorting in a radar station a group air target from the class “aircraft with turbojet engines” when exposed to speed-guiding interference, the signal being reflected from the group air target at an intermediate frequency from the output of the radar station receiver is subjected to narrow-band Doppler filtering based on The fast Fourier transform procedure is also converted into the amplitude-frequency spectrum, the components of which are caused by signal reflections from airframes of the group and rotating blades of the impeller of the low pressure compressor of their power plants, the Doppler frequency count is determined, which corresponds to the maximum amplitude of the spectral component of the signal spectrum, which is caused by its reflection from the glider of one of the group’s planes, left and right in the frequency band ± ΔF, where ΔF is a priori a given Doppler frequency band occupied by spectral components due to signal reflections from the gliders of the group’s airplanes, relative to the frequency of the spectral component the spectrum of the signal with the maximum amplitude, the samples of the Doppler frequencies of the local maxima of the signal spectrum and their number that exceed the set threshold are determined, the samples of the Doppler frequencies of the local maxima having the largest amplitudes are determined, the number of which is equal to the number of local maxima located in the Doppler frequency band ± ΔF relative to spectral component with a maximum amplitude corresponding to the reflection of the signal from the glider of one of the group’s planes, and on the right, at frequencies exceeding the ΔF value, relative to the frequency of the spectral component having the maximum amplitude, which are caused by signal reflections from the impeller blades of the first stages of the low-pressure compressor of the group aircraft engine, characterized in that the optimal multidimensional linear discrete Kalman filtering procedure is calculated in accordance with the expressions

Where

- filter cycle number; K is the total number of clock cycles of the filter; P ^- (k + 1) and P (k + 1) are the covariance matrices of extrapolation and filtering errors, respectively; Ф (k) - transition state matrix; Q (k + 1) and R (k + 1) are the covariance matrices of excitation and observation noise, respectively; S (k + 1) is the matrix of weights; I is the identity matrix;

and

- respectively, the state vector of current and extrapolated estimates containing estimates of Doppler frequencies due to the approximation rates of each j-th,

A group aircraft with a radar carrier; J is the number of aircraft in the group; H (k) is the observation matrix; Y (k) is the observation vector of samples of Doppler frequencies; Z (k + 1) - matrix of measurement residuals; Ψ (k + 1) is the matrix of a priori filtering errors; "-1" - inverse matrix calculation operation; "t" is the transpose of the matrix, accompanied by the Doppler frequency of each j-th,

, the glider component of the signal spectrum, due to the approach speed of each j-th,

, of an aircraft of a group with a carrier of a radar station, and the dimension of the matrices included in procedure (1) - (6) is determined by the number of local maxima of the spectral components of the signal in the frequency band ± ΔF relative to the spectral component with a maximum amplitude corresponding to the reflection of the signal from the glider one of the aircraft of the group, according to the detected samples of the Doppler frequencies of local maxima located on the right at frequencies exceeding the ΔF value and corresponding to the signal reflections from the blades of the wheels of the first stages of the low-pressure compressor of the engines of the group’s aircraft, the Doppler frequency of the centroid is calculated as the average value of the samples of the Doppler frequencies of the local maxima, which is fed to the input of the optimal filter of the centroid tracking of the Doppler frequencies caused by the reflection of the signal from the blades of the impeller of the first stages of the low-pressure compressor of the engines planes of a group operating in the same way as the optimal filter for tracking glider components with ektra signal in accordance with the procedure (1) - (6) for each k-th clock cycle of operation both optimal tracking filters calculated difference evaluation

between the estimated Doppler frequencies corresponding to the centroid of the Doppler frequency

due to reflections of the signal from the blades of the impeller of the first stages of the low-pressure compressor of the aircraft engines of the group, and reflections of the signal from the glider

every j-th plane of the group,

, the modules of the derived estimates of the differences are calculated

between estimated Doppler frequencies

due to the reflections of the signal from the glider of each j-th group aircraft and the centroid of the Doppler frequency

due to reflections of the signal from the impeller blades of the first stages of the low-pressure compressor of the group's aircraft engines, which are compared with a threshold value ε close to zero, when the condition

for all j's,

, estimates of the glider components of the spectrum of the signal, which corresponds to the absence of the effect of noise leading away in speed, all estimates are used as output information

,

Doppler frequencies calculated in accordance with procedure (1) - (6) based on the observation of Y (k), if the condition

for all

which corresponds to the effect of noise leading away in speed at the output, along with estimates of Doppler frequencies

where

; M - the number of estimates of Doppler frequencies that are not identified as speed-leading noise, estimates of Doppler frequencies are formed

where

; N is the number of estimates of Doppler frequencies that are identified as speed-leading interference; J = M + N calculated according to the procedure

Where

,

- a transition state matrix, the numerical values of the elements of which are determined on the basis of a correlation analysis of the current values of the estimates of Doppler frequencies

,

received until the moment when the condition was met

, and subsequently identified as speed-leading interference;

- estimated state vector containing an estimate of the Doppler frequency

,

obtained after its identification as a speed-guiding interference, only on the basis of a transition state matrix

taking into account the model of mutual movement of the radar carrier and that group aircraft, the signal reflected from which was not yet initially identified as a speed-guiding interference.

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