RU2810525C1 - Method for determining planned coordinates of air target using multi-position radar system built into spatially distributed radio interference system - Google Patents

Abstract

FIELD: radars.

SUBSTANCE: invention relates to a method for determining the planned coordinates of an air target in a multi-position radar system (MPRS) built into a spatially distributed radio interference system, based on an analysis of the response received in a single bistatic link “transmitter-target-receiver”. In the claimed method, an MPRS is used, built into a spatially distributed radio interference system and using the interference signal of an automated jamming station (AJS) transmitter to illuminate targets. The K-channel MPRS receiving device consists of K antennas (k =1, 2, ..., K) forming an antenna array with one central antenna and K-1 peripheral antennas, K receivers, K analogue-to-digital converters (ADC), K-channel digital computer and frequency synthesizer. In the claimed method, independent correlation processing of the transmitter signal reflected from the target is carried out in each channel of the receiving device with the determination of estimates of the delay and phase of the target responses at the points of maximum of the correlation function, the formation of a column vector of estimates of the delay of the responses of the air target registered in each channel of the receiving device, and a column vector of coefficients caused by the phase shift of the responses recorded in the central and in each peripheral channel of the receiving device. A directivity matrix of the antenna array is formed, depending on its geometric parameters and determining the phase shifts of the signals in each peripheral antenna relative to the signal in the central antenna. The direction of arrival of the signal reflected from the air target is assessed, estimation of the target-central antenna distance, and using these values an estimate of the target's rectangular coordinates is obtained.

EFFECT: determining the coordinates of an air target in the MPRS based on an analysis of the response received in a single bistatic link “transmitter-target-receiver”.

1 cl, 10 dwg

Description

The invention relates to a method for determining the planned coordinates of an air target in a multi-position radar system (MPRS), built into a spatially distributed radio interference system, based on an analysis of the response received in a single bistatic link “transmitter-target-receiver”.

MPRLS are known [1-8], which, for the purpose of multifunctional use of radio systems, are created on the basis of a spatially distributed radio suppression system for consumer navigation equipment (CNA) of the global navigation satellite system (GNSS) [5-8]. Such MPRLS consist of N radio interference transmitters and M receivers of signals reflected from targets. The transmitters emit phase-code-manipulated pseudo-random sequence (PSKP) jamming signals, which, in addition to the main function of radio suppression of GNSS NAP, additionally perform the function of target illumination. Receivers of signals reflected from targets are synchronized with each other and with jammers and are connected by communication lines with the control point. In this case, at the control point, to determine the coordinates of an air target, the total-rangefinder or difference-rangefinder positioning method is used.

However, to implement these methods, it is required that at the stage of primary processing in the MPRLS, the target response is detected in at least two (for 2D positioning) or three (for 3D positioning) signal processing channels (bistatic links “transmitter-target-receiver”) . This is the main disadvantage of such an MPRLS, since in conditions of low power transmitter-receiver radio links and the use of small-sized air targets with a small effective scattering surface, the signal-to-noise ratio in the channels of primary signal processing will be small and the signal at their outputs will exceed the established detection threshold in one channel, for which the total “transmitter-target-receiver” range will be minimal. In this case, determining the coordinates of an air target using sum-rangefinder or difference-rangefinder positioning methods becomes impossible.

In addition, the disadvantage of such an MPRLS is the need to implement high-capacity data lines to transmit signals from different receiving positions to the control point to determine the coordinates of the target using one of the specified methods.

The technical solution is aimed at determining the coordinates of an air target in an MPRLS built into a spatially distributed radio interference system, based on an analysis of the response received in a single bistatic link “transmitter-target-receiver”.

The technical result is achieved by the fact that in a multi-position radar system built into a spatially distributed radio interference system and using the interference signal of an automated jamming station (ASP) transmitter to illuminate targets, a K -channel receiving device consisting of K antennas ( k = 1, 2 , ..., K ), forming an antenna array with one central antenna and K -1 peripheral antennas, K receivers, K analog-to-digital converters (ADC), K -channel digital computer, frequency synthesizer and providing:

- independent correlation processing of the transmitter signal reflected from the air target in each channel of the receiving device with determination of estimates of the delay and response phase of the air target at the maximum points of the correlation function;

- formation of a column vector of estimates of the delay of responses of an air target, registered in each channel of the receiving device, and a column vector of coefficients due to the phase shift of responses recorded in the central and in each peripheral channel of the receiving device;

- formation of the antenna array directivity matrix, which depends on its geometric parameters and determines the phase shifts of the signals in each peripheral antenna relative to the signal in the central antenna when a signal arrives from a given direction;

- assessment of the direction of arrival of the signal reflected from the air target, based on the maximum of the spatial spectrum, obtained by multiplying the directional matrix of the antenna array and the phase shift vector of the received signal;

- estimation of the “target-central antenna” distance, obtained using the known value of the direction to the ASP transmitter, the estimated value of the direction to the air target from the location of the central antenna of the receiving device, the known value of the “transmitter-central antenna” range and the estimated value of the total “transmitter” range -target-central antenna”, obtained on the basis of the estimated value of the response delay of the air target, registered in the central channel of the receiving device;

- assessment of the rectangular coordinates of the air target based on the estimated value of the “target-central antenna” distance and the estimated value of the direction to the air target from the location of the central antenna of the receiving device.

The essence of the invention is illustrated by drawings.

In fig. 1 shows a diagram of a goniometric-elliptical MPRLS; Fig. 2 shows the signal $$S_k\left(t\right)$$ transmitter 1 of the automated jamming station, reflected from an air target and received by antenna 2.1.k of the antenna array 2.1 of the receiving device 2, in FIG. 3 showing the spectrum of the signal reflected from an air target $$S_k\left(t\right)$$ at zero frequency, Fig. Figure 4 shows the real part of a complex digital signal at zero frequency , in fig. Figure 5 shows the real (a), imaginary (b) components and envelope (c) of the correlation function , in fig. 6 shows the spatial spectrum P of the signal reflected from an air target and received by the antenna array 2.1; FIG. 7 shows an illustration of the process of estimating the coordinates of an air target using the goniometric-elliptical method; FIG. 8 shows Table 1 containing the antenna array parameters used for numerical simulation; FIG. 9 shows Table 2 containing the initial data and results of numerical simulation modeling; FIG. Figure 10 graphically shows the results of numerical simulation modeling.

A method for determining the planned coordinates of an air target using a multi-position radar system built into a spatially distributed radio interference system is implemented in an MPRLS, which consists of an automated jamming station (ASP) transmitter 1, a K -channel receiver 2, consisting of K antennas 2.1. k ( k =1, 2, …, K ), forming an antenna array 2.1 with one central antenna 2.1.1 and K -1 peripheral antennas 2.1. k ( k =2, 3, …, K ), located at the nodes of a regular ( K -1)-gon, K receivers 2.2. k ( k =1, 2, …, K ), K analog-to-digital converters (ADC) 2.3. k ( k =1, 2, …, K ), K -channel digital computer 2.4, frequency synthesizer 2.5 (Fig. 1).

The geometric center of the central antenna 2.1.1 is the origin of the rectangular horizontal Cartesian coordinate system XOY , and the polar coordinates of the peripheral antennas 2.1.k ( r,φ _k ) are given, where r=λ/2 is the radius of the antenna array (the distance between the central antenna 2.1.1 and peripheral antennas 2.1.k), equal to half the wavelength λ of the interference signal, and the angle φ _k is counted counterclockwise from the OX axis and is determined based on the expression

. (1)

The rectangular coordinates of the 2.1.k peripheral antennas are determined from the expressions

, (2)

. (3)

The rectangular coordinates ( xP _, yP ₎ of the transmitter 1 ASP are known, and _the polar coordinates ( rP _, φP ) are determined based on the expressions

$$r_{\text{P}}={\left(x_{\text{P}}^2+y_{\text{P}}^2\right)}^{\frac{1}{2}}$$ , (4)

$${\phi }_{\text{P}}=arctg\left(\frac{y_{\text{P}}}{x_{\text{P}}}\right)$$ .(5)

The method for determining the planned coordinates of an air target using a multi-position radar system built into a spatially distributed radio interference system is carried out as follows.

1. Transmitter 1 ASP generates and emits an interference PCM signal

$$S\left(t\right)=AG\left(t\right)\cos \left(2\pi f_{0}t+\psi \right)$$ , (6)

where A is the signal amplitude, G(t) is the pseudo-random sequence (PSR), f ₀ is the carrier frequency of the signal, ψ is the initial phase of the signal.

2. The emitted signal of the ASP transmitter 1 is reflected from the air target 3 with coordinates ( x, y ), located in the radio visibility zone of the MPRLS, and is received at the input of the K- channel receiving device 2 (Fig. 1).

3. In each k -th channel of the receiving device 2 the following operations are carried out:

- the signal reflected from the air target 3 is received by antenna 2.1. k of the antenna array 2.1 and without taking into account the Doppler frequency shift has the form (Fig. 2)

, (7)

WhereA _k - amplitude of the signal reflected from the target, - signal delay, determined by the relative position of the transmitter, receiver and target

, (8)

Where - distance “transmitter 1-target 3”, - distance “target 3-antenna 2.1. k ", c - speed of light.

- from the antenna output 2.1. k signal goes to receiver 2.2. k , where it is selected, amplified and its spectrum is transferred to zero frequency (Fig. 3).

- from the receiver output 2.2. k signal at zero frequency is supplied to ADC 2.3. k , where its analog-to-digital conversion is carried out with the formation of complex samples of the digital signal at zero frequency , Where $$\Delta t$$ - sampling interval, i - number of discrete sample (real part shown in Fig. 4).

4. From the outputs of the ADC 2.3.k digital signals at zero frequency , enter the K -channel digital computer 2.4, where the following operations are carried out in each k -th channel:

- treatment in a filter matched with the PSP of transmitter 1 ASP, with the formation of a complex correlation function (Fig. 5 a, b)

, (9)

, (10)

, (eleven)

where L is the length of the PSP in discrete samples, $$m=\frac{\tau }{\Delta t}$$ - time shift (delay) of the signal in the matched filter in discrete samples (varies within the limits of the PSP length m =1, ..., L );

- calculation of the envelope of the correlation function (Fig. 5c)

$$X_k\left(m\Delta t\right)=\sqrt{I_k^2\left(m\Delta t\right)+Q_k^2\left(m\Delta t\right)}$$ . (12)

- calculation of the standard deviation (RMS) of the correlation function samples $${\sigma }_X$$ , on the basis of which the threshold for detecting an air target 3 is calculated for a given false alarm probability P _lt under the assumption of the Rayleigh nature of the noise distribution of the envelope of the correlation function

$$H={\sigma }_X\sqrt{-\ln P_{\text{lt}}}$$ ; (13)

- determination of the maximum value correlation function envelope, which is compared with the detection threshold, while air target 3 is considered detected if the value of the correlation function envelope exceeds the detection threshold

$$X_{k,\max }>H$$ , (14)

- in case of detection of an air target 3, the corresponding reference number of the envelope of the correlation function is determined

, (15)

- an estimate of the target response delay in the kth channel is determined

, (16)

- the signal phase estimate is determined at the moment of recording the response in the kth channel

$${\widehat{\psi }}_k=arctg\left\{\frac{Q_k\left(\widehat{m}\Delta t\right)}{I_k\left(\widehat{m}\Delta t\right)}\right\}$$ . (17)

The primary signal processing operations listed in paragraphs 3 and 4 independently carried out in each channel of the receiving device 2, provided that all clock and reference frequencies in all K channels are generated from one frequency synthesizer 2.5.

5. As a result of primary signal processing in all K channels of the receiving device 2 in the digital computer 2.4, a column vector of size K x1 estimates the response delay of the air target 3 is formed

(18)

and a column vector of size K x1 of estimates of the phase of the signal reflected from the air target 3

, (19)

which serve as input data for the following secondary processing operations carried out in digital computer 2.4:

- vector is converted into a column vector (size ( K -1)x1) of coefficients caused by the phase shift of the signals reflected from the air target 3 and registered in the central and in each peripheral channel of the receiving device 2,

, (20)

Where . Vector $$\Delta \Psi$$ contains the necessary information about the direction of arrival of the signal reflected from the air target 3;

- for the entire 2.1 K -element antenna array in the angular range $$\phi =0\mathrm{...}2\pi$$ in increments $$\Delta \phi$$ The directivity matrix A is determined, depending on the geometric parameters of the antenna array 2.1. The matrix size will be ( N x( K -1)), where $$N=\frac{2\pi }{\Delta \phi }$$ -number of directions (directional matrix rows). Element a ( n,k ) of the directivity matrix determines the phase shift of the signal in the central antenna 2.1.1 and the k -th peripheral antenna 2.1. k with angular coordinate when a signal arrives from the nth direction $${\phi }_n=n\Delta \phi$$

;(21)

- the spatial spectrum P of the signal reflected from the air target 3 and received by the antenna array 2.1 is formed by multiplying the directionality matrix and the phase shift vector of the received signal

. (22)

The spatial spectrum P is a column vector of size ( N x1) (Fig. 6);

- the assessment is determined direction of arrival of the signal reflected from the air target 3 and received by the antenna array 2.1, as the direction corresponding to the maximum value of the received spatial spectrum

; (23)

- distance is estimated “target 3-central antenna 2.1.1”, based on the expression

,(24)

Where - the angle between the direction to the ASP transmitter 1 and the estimated direction to the air target 3 from the location of the central antenna 2.1.1, - assessment of the total range “transmitter 1-target 3-central antenna 2.1.1”, -range “transmitter 1-central antenna 2.1.1”, equal to the polar coordinate location points of the transmitter 1 ASP (Fig. 7);

- using the estimated values of the distance “target 3-central antenna 2.1.1” and the direction to the air target 3 from the location of the central antenna 2.1.1, the rectangular coordinates of the air target 3 are estimated

, (25)

. (26)

The parameters of the antenna array 2.1 used for numerical simulation are presented in Table 1 in Fig. 8.

Rectangular coordinates of the receiving device 2 (the geometric center of the central antenna 2.1.1 of the antenna array 2.1), the ASP transmitter 1 and the true coordinates of the air target 3, used in the modeling as initial data, as well as an estimate of the direction to the air target 3 and estimates of the coordinates of the air target 3 , obtained during numerical simulation, are presented in Table 2 in Fig. 9.

Graphically, the results of numerical simulation of determining the coordinates of air target 3 in the MPRLS are shown in Fig. 10, where the ASP transmitter 1 is shown as a diamond, the receiver 2 is indicated by a square, the true position of the air target 3 is shown by a cross, and the estimated position of the air target 3 is indicated by a star.

Analysis of Fig. 9 and fig. 10 shows that the proposed angular-elliptical MPRLS, built into a spatially distributed radio interference system and implementing the proposed method for determining the coordinates of an air target 3, provides high accuracy measurement of the coordinates of an air target 3, the response of which is recorded in a single bistatic link “transmitter-target-receiver” "

Thus, the proposed method for determining the planned coordinates of an air target using a multi-position radar system built into a spatially distributed radio interference system provides determination of the coordinates of an air target based on an analysis of the response registered in a single bistatic link “transmitter-target-receiver” in the MPRLS built-in into a spatially distributed radio interference system, the receiving position of which is equipped with a 2.1 antenna array.

The developed method provides an air target positioning accuracy of 30-50 m with a total range of the bistatic link “transmitter-target-receiver” of 15-20 km and a direction finding error of no more than 1.

A source of information

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4. Kiryushkin V.V., Cherepanov D.A. Coordinates estimation of the air target in the multiitem observation system “navigation satellites -the air target -the ground receiver” J. Sib. Fed. Univ. Eng. technol., 2016, 9(8), 1172-1182. DOI: 10.17516/1999-494X-2016-9-8-1172-1182.

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6. Zhuravlev A.V., Kiryushkin V.V., Babusenko S.I., Markin V.G. Simulation modeling of the process of primary signal processing in the receiver of a multi-position radar system based on special emitters // Radiotekhnika.2020. T. 84. No. 6(12). pp. 58-66. DOI: 10.18127/j00338486-202006(12)-10.

7. Shuvaev V.A., Zhuravlev A.V., Kiryushkin V.V., Babusenko S.I. Experimental verification of the possibility of recording responses from air targets in a multi-position radar system based on special emitters // Radio engineering. 2020. T. 84. No. 6(12). pp. 121-130. DOI: 1018127/j00338486-202006(12)-19.

8. Patent No. 2734690 RF, IPC G01S 5/02, G01C 21/04. Method for determining the coordinates of an air target in a multi-position ground surveillance system Radio transmitters-air target-receiver / A.V. Zhuravlev, A.F. Ivanov, V.V. Kiryushkin and others (RF); Open joint-stock research and development enterprise PROTEK (RF). - No. 2019143788; Declared 12/23/2019; Publ. 10/22/2020, Bulletin. 30. - 12 p.: 1 ill.

Claims (7)

A method for determining the planned coordinates of an air target using a multi-position radar system (MPRS), built into a spatially distributed radio interference system and using the interference signal of an automated jamming station (ASP) transmitter to illuminate air targets, characterized in that the MPRLS uses a K -channel receiving a device consisting of K antennas ( k =1, 2, ..., K ) forming an antenna array with one central antenna and K -1 peripheral antennas, K receivers, K analog-to-digital converters (ADC), K -channel digital computer, frequency synthesizer and providing: - independent correlation processing of the transmitter signal reflected from the air target in each channel of the receiving device with determination of estimates of the delay and response phase of the air target at the maximum points of the correlation function; - formation of a column vector of estimates of the delay of responses of an air target, registered in each channel of the receiving device, and a column vector of coefficients due to the phase shift of responses recorded in the central and in each peripheral channel of the receiving device; - formation of the antenna array directivity matrix, which depends on its geometric parameters and determines the phase shifts of the signals in each peripheral antenna relative to the signal in the central antenna when a signal arrives from a given direction; - assessment of the direction of arrival of the signal reflected from the air target, based on the maximum of the spatial spectrum, obtained by multiplying the directional matrix of the antenna array and the phase shift vector of the received signal; - estimation of the “target - central antenna” distance, obtained using the known value of the direction to the ASP transmitter, the estimated value of the direction to the air target from the location of the central antenna of the receiving device, the known value of the “transmitter - central antenna” range and the estimated value of the total “transmitter” range - target - central antenna”, obtained on the basis of the estimated value of the response delay of the air target, registered in the central channel of the receiving device; - assessment of the rectangular coordinates of the air target based on the estimated value of the distance “target - central antenna” and the estimated value of the direction to the air target from the location of the central antenna of the receiving device.