RU2765873C1 - Method for viewing the space - Google Patents

Abstract

FIELD: radar technology.

SUBSTANCE: invention relates to radar technology and can be used to survey space. A directional pattern scans according to azimuth, sequential data processing is performed in discrete time, a fan-shaped transmitting directional pattern is formed in each azimuthal position in transmission mode, a receiving directional pattern is formed in reception mode, each beam of which has a needle shape, and neighboring beams overlap at half power level, while the width of the receiving and transmitting directional patterns corresponds to the angular size of the detection zone, objects are detected, their speed, the range and angular coordinates are measured using the monopulse signal processing method. If, according to the measured values of the range and speed of the detected object, according to a pre-accepted criterion, a decision is made on the need to clarify the coordinates of the object, then the transmitting and receiving directional patterns are moved by electronic scanning to one of the previous azimuthal positions, the range and angular coordinates of the selected object are measured, after moving the transmitting and receiving directional patterns space survey is continued.

EFFECT: reduction in the time required to trace the selected objects.

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Description

The invention relates to radar technology, and in particular to methods for surveying space, and is intended for use in radar systems (RLS) with digital antenna arrays (DAR).

A known way to view the space [1 - p. 39 - Signal processing in multi-channel radar / Ed. A.P. Lukoshkin. M.; Radio and communication. 1983 - 328 S.] by parallel review of all measured coordinates using a multi-beam radar, while forming overlapping beams of the radiation pattern (DN), covering the entire viewing area.

The disadvantages of the known method are the redundant resources required for the formation of parallel beams in all measured coordinates.

There is a known way of viewing space [2 - p. 233 - Belotserkovsky G.B. Fundamentals of radar and radar devices. M.; Owls. radio. 1975 - 336 p.], in which a multibeam DN is formed in the elevation plane due to the irradiation of the reflector antenna with several emitters (horns), while the line of emitters is located in the elevation plane and is fixed relative to the axis of the mirror, each emitter is connected to its transceiver by a separate feeder and forms a partial beam at its carrier frequency. Reception of the reflected signals by each emitter is also carried out at its own frequency. Scanning in azimuth is carried out by mechanical rotation of the antenna.

The disadvantages of the known method of viewing space are:

- low efficiency of the transmitting part of the device due to large losses of the emitted and received signal in the feeders connecting the emitters (horns) and the receiving-transmitting channels, since they are significantly separated in space;

- insufficiently high reliability, since if one transceiver fails, the view of space becomes impossible in the sector of the elevation view that this transceiver provided.

A known method of viewing space [3 - Method of viewing space and tracking surface objects during low-altitude flight - RF Patent 2211459, publ. 08/27/2003], which consists in the fact that the detection of objects includes sequential processing of data in discrete time with reference to each current cycle t _n of processing obtained during the survey of space using a fan-shaped radiation pattern and occupying M horizontal positions and a radiation pattern with a needle shape , probing separate selected sections of the view area with a short survey period, while both radiation patterns are formed by one antenna system with electronic beam control.

The disadvantages of the known method of viewing space are:

- long survey time, since the measurement of the object's coordinates is carried out in two stages: first, a fan-shaped RP is used in the receive and transmit mode, while a rough measurement of the object's coordinates is performed, and to clarify the coordinates, an RP with a needle shape is additionally used, which significantly lengthens the survey time at increasing the number of objects;

- insufficient accuracy of measuring the coordinates of the object, since a single DN with a needle shape is used for measurement, and the maximum method [2 - p. 87].

The closest in technical essence to the invention is a way to view space [4 - Way to view space - RF Patent 2610833, publ. February 16, 2017], taken as a prototype, in which they scan the radiation pattern in azimuth, while sequential data processing is performed in discrete time with reference to each azimuth position of the radiation pattern, a multi-element digital antenna array is used to form the transmitting and receiving radiation patterns, at the same time, in each azimuth position of the radiation pattern in the transmission mode, a transmitting fan-shaped radiation pattern is formed in the elevation plane, in the reception mode, the received reflected signals are presented in the form of digital readings, from which, by weighted summation, a receiving multipath radiation pattern is formed in the elevation plane, each beam of which has a needle shape, and adjacent beams overlap at the half power level, while the width of the receiving and transmitting radiation patterns corresponds to the angular size of the detection zone in the elevation plane, detection is performed objects, measuring their range and elevation coordinates by a monopulse signal processing method for each of the adjacent pairs of receiving beams.

The disadvantage of the prototype is a long space scanning period, which can be several seconds, while from review to review, the coordinates of an object with a high speed of movement can change significantly.

The technical problem to be solved by the invention is to reduce the period of measurement of the coordinates of the selected objects.

To solve this technical problem, a method for surveying space is proposed, in which they scan the radiation pattern in azimuth, while sequential data processing is performed in discrete time with reference to each azimuth position of the radiation pattern, a digital antenna array is used to form the transmitting and receiving radiation patterns, while in each azimuthal position of the radiation pattern in the transmission mode, a transmitting fan-shaped radiation pattern is formed in the elevation plane; in the reception mode, the received reflected signals are presented in the form of digital readings, from which, by weighted summation, a receiving multipath radiation pattern in the elevation plane is formed, each beam of which has a needle-shaped shape, and adjacent beams overlap at the half power level, while the width of the receiving and transmitting radiation patterns corresponds to the angular size of the detection zone in the elevation plane axis, detect objects, measure their speed, range and elevation coordinates by a monopulse signal processing method for each of the neighboring pairs of receiving beams having the same azimuth coordinate.

According to the invention, in the event that, according to the measured values of the range and speed of the detected object, according to a predetermined criterion, a decision is made on the need to clarify the coordinates of the object, then from the m-th azimuthal position, the transmitting and receiving radiation patterns are moved by electronically scanning them to one of the k previous azimuth positions corresponding to the expected direction to the selected detected object, where k can take a value from 1 to m-1, the range and elevation coordinates of the selected object are measured, after which the transmitting and receiving radiation patterns are moved by electronically scanning them to the azimuthal position m + 1 and continue the survey of space by scanning the radiation pattern in azimuth.

The technical result is to reduce the time of tying the route of the selected objects due to the more frequent measurement of their coordinates.

The comparative analysis of the claimed method and the prototype shows that their difference is as follows:

- in the prototype, the object coordinates are measured with a space scanning period, which can be several seconds, while the coordinates of an object moving at a high speed during this time can change greatly. In the proposed method, the period of measurement of the coordinates of the selected objects, the parameters of which correspond to a predetermined criterion, for example, with a high speed of movement, is reduced, which provides more accurate tracking of objects than in the prototype;

- in the prototype, the object trace is tied after several space scanning periods, which can be several seconds. In the proposed method, the period of tying the route of the selected objects is reduced due to the more frequent measurement of their coordinates.

The combination of distinguishing features and properties of the proposed method of viewing space from the literature is not known, so it meets the criteria of novelty and inventive step.

In FIG. 1 shows a block diagram of a device that provides the implementation of the proposed method.

In FIG. 2 shows a block diagram of the control system and digital diagramming.

In FIG. 3 shows a block diagram of the frequency converter.

In FIG. 4 shows a block diagram of the control module and digital signal processing.

When implementing the proposed method, the following sequence of actions is performed:

- scan the radiation pattern in azimuth, while performing sequential data processing in discrete time with reference to each azimuth position of the radiation pattern - 1;

- to form the transmitting and receiving radiation patterns, a digital antenna array is used, while in each azimuth position of the radiation pattern in the transmission mode, a transmitting fan-shaped radiation pattern is formed in the elevation plane - 2;

- in the receiving mode, the received reflected signals are presented in the form of digital readings, from which, by weighted summation, a receiving multibeam radiation pattern is formed in the elevation plane, each beam of which has a needle shape, and neighboring beams overlap at the half power level, while the width of the receiving and transmitting diagrams directivity corresponds to the angular size of the detection zone in the elevation plane -3;

- perform the detection of objects, the measurement of their speed, range and elevation coordinates monopulse signal processing method for each of the neighboring pairs of receiving beams having the same azimuthal coordinate - 4;

- if, based on the measured values of the range and speed of the detected object, according to a predetermined criterion, a decision is made on the need to clarify the coordinates of the object, then from the m-th azimuthal position, the transmitting and receiving radiation patterns are moved by electronically scanning them to one of the k previous azimuthal positions , corresponding to the intended direction to the selected detected object, where k can take a value from 1 to m-1 - 5;

- measure the range and elevation coordinate of the selected object, then move the transmitting and receiving radiation patterns by electronically scanning them to the azimuth position m + 1 and continue viewing the space by scanning the radiation pattern in azimuth - 6.

The proposed method can work both with electronic scanning of the radiation pattern (RP) in azimuth with a fixed digital antenna array (DA) and with scanning of RP in azimuth due to the mechanical movement (rotation) of the DA.

The implementation of the proposed method for viewing space is possible, for example, using a device that includes (Fig. 1) CAR 1, a control unit (CU) 2, the first control output of which is connected to the control input of the control system and digital diagramming (SUTSDO) 7, which is control input CAR 1, the second control output - to the control input of the turntable (OPU) 3, the third control output - to the control input of the unit for detecting and measuring the coordinates of objects (BOIKO) 4, and the input - to the output BOIKO 4.

CAR 1 includes N transceiver modules (TRM) 5, a signal generation and distribution system (SFRS) 6, and a control and digital diagramming system SUTSDO 7.

SFRS 6 has N outputs of the probing signal (SS) connected to the inputs of the SS PPM 5, N sampling outputs Fd connected to the sampling inputs of the PPM 5, N outputs of the local oscillator Fget connected to the heterodyne inputs of the PPM 5.

PPM 5 contain series-connected phase shifter (PV) 8, solid-state power amplifier (PA) 9, circulator 10 and antenna element (AE) 11. Series-connected low-noise amplifier (LNA) 12, frequency converter (FR) 13 are connected to the output of circulator 10, the heterodyne input of which is the heterodyne input of the PPM 5 and the control and digital signal processing module (DSP) 14, the sampling input of which is the sampling input of the PPM 5.

The data output of the MUTsOS 14 is the data output of the MTS 5 and is connected to one of the N data inputs of the MUTs 7, the control input of the MUTsOS 14 is the control input of the MTS 5 and is connected to one of the N control outputs of the MTS 7. The first, second and third control outputs of the MUTs 14 are connected respectively with the control inputs of the frequency converter 13, PA 9 and phase shifter 8. The data output of the SUTSDO 7 is connected to the data input of the BOIKO 4.

SUTSDO 7 (Fig. 2) has K shapers 15 according to the number of formed beams, each of which contains N channels, while the inputs of the i-th channels in the shapers 15 are combined. Each channel of the shaper 15 contains a multiplier 16, the first input of which is the input of the channel, the output of read-only memory (ROM) 17 is connected to the second input, and the output of the multiplier 16 is the output of the channel and is connected to one of the N inputs of the digital adder 18, the output of which is connected to one of the K inputs of the interface (I) 19. The output of the interface 19 is the data output of the SDDS 7. The control device (CU) 20, whose input is the control input of the SDDS 7, has N + 1 control outputs, which are the control outputs of the SDDS 7. All blocks SUTSDO 7 can be performed, depending on the number of PPM 5 and the number of beams K, in the form of one or more programmable logic integrated circuits (FPGA).

PFC 13 (Fig. 3) is a series-connected mixer (SM) 21, the input of which is the input of the PFC 13, and the heterodyne input is the heterodyne input of the PFC 13 and the intermediate frequency amplifier (IF) 22, the output of which is the output of the intermediate frequency (IF) PFC 13, and the control input - the control input of the PFC 13.

MUTSOS 14 (Fig. 4) is a serially connected analog-to-digital converter (ADC) 23, the input of which is the input of the IF MUTSOS 14, and the clock input is the sampling input of the MUTSOS 14 and the control and processing unit (CUO) 24. The first, second and the third control outputs of the VCU 24 are, respectively, the first, second and third control outputs of the MUCM 14. The data output and the control input of the VCU 24 are, respectively, the data output and the control input of the MUCM 14.

SFRS 6 consists of three frequency synthesizers that provide the formation of a probing signal SS, a signal of the sampling clock frequency Fd, and a local oscillator signal Fhet. This can be used, for example, synthesizers from [5 - pp. 142-143. Mini Circuits. RF & Microwave components guide. 2010]. The signals generated in the synthesizers are branched out by HaN outputs with the help of power dividers [5 - pp. 136-140].

BOYKO 4 is a computer that provides processing of signal samples according to a given algorithm.

BU 2 is a computer that controls the operation of the devices TsAR 1, OPU 3 and BOYKO 4, as well as displaying the coordinates of detected objects.

OPU 3 is a device that provides rotation of the CAR 1 in the azimuthal plane, and can be made on the basis of a slewing ring with a bearing and a worm shaft with an electric motor.

The device can operate both during electronic scanning of the RP in azimuth with a fixed CAR 1, and when scanning the RP in azimuth due to the mechanical rotation of the CAR 1 using the OPA 3. The scanning sector in azimuth in the first case is limited by the characteristics of the CAR 1, and in the second case it is equal to 360°.

In each azimuthal position of the RP in the transmission mode, a fan-shaped transmitting directional pattern is formed in the elevation plane using the CA 1. The formation of the transmitting RP is carried out by setting the required phase and amplitude ratios in the PPM 5 from the CA 1 by adjusting the phase shift of the ES probing signal in the phase shifters 8 and the coefficient amplification of power amplifiers PA 9.

For the case of a flat rectangular CAR, the aperture of which contains N _x AE 11 installed along the X coordinate at a distance d _x , and N _v AE 11 installed along the Y coordinate at a distance d _y , the radiation pattern F(ϕ,θ) is defined as [ 6 - pp. 27-28, Kuzmin S.Z. Digital radar. Introduction to theory. - CVIC. 2000]:

where A _xi ,A _yi - coefficients of the amplitude distribution in the PA 9 connected to the AE 11, which are located along the X and Y coordinates, respectively;

ψ _x1 , ψ _y1 - phase distribution coefficients, presented in the form of phase shifts in the phase shifters 8, connected through the AM 9 and the circulator 10 with the AE 11, which are located along the X and Y coordinates, respectively.

For ground-based surveillance radars, a fan pattern can have a cosecant shape [7 - fig. 5.1 b - Bakulev P.A. radar systems. Moscow: Radio engineering. 2007. - 376 p.]. This form of DN is formed by setting the appropriate amplitude and phase coefficients in power amplifiers 9 and phase shifters 8, for example, as described in [8 - Lopatenko E.V., Marusich A.A. cosec antenna pattern with low side lobes. // Radio engineering, 2006, No. 12, p. 49-53].

After amplifying the probing signal of the ES in the PA 9, it is fed to the antenna element (AE) 11 connected to this channel through the connecting circuit of the minimum length.

After the emission of the probing signal from the ES, the CAR 1 switches to the receive mode.

In the reception mode, the received reflected signals from the output of each AE 11 in each PPM 5 pass through the circulator 10, are amplified in the LNA 12, converted in frequency in the TX 13 and presented as digital samples S _mn (t) using the ADC 23.

From the received digital readings, receiving multibeam DNs in the elevation plane with needle-shaped rays are formed by weighted summation in the SUTsDO 7.

The readings of the i-th beam with the direction of the maximum ϕ _i , θ _i are calculated by multiplying the digital stream from each ADC 23 in multipliers 16 by the weight factor W _mn (ϕ _i ,θ _i ) from the ROM 17 and summing in a digital adder

18. The radiation pattern for the i-th beam has the form

where

The number of beams K in each pattern is determined by the required field of view in the elevation plane and the width of one beam. The beams of the receiving multibeam RP are needle-shaped, located in the elevation plane, while the direction of their maxima ensures the overlap of adjacent beams at the level L from the maximum. The value of L can be taken as half of the maximum (half power) or another value, depending on the algorithm of the equipment. The width of the receiving radiation pattern corresponds to the angular size of the detection zone in the elevation plane.

The generated readings K of the receiving beams from the outputs of the shapers 15 are sent to the interface 19, where they are converted into a serial form and transmitted in the form of serial codes to the BOYKO 4, where in each of the neighboring pairs of the formed receiving beams, objects are detected, for example, moving, their range is measured and elevation coordinates corresponding to the elevation and azimuth position of those receiving beams in which they were detected [9, pp. 185-189 - Handbook of radar / Ed. M.I. Skolnik. Moscow: Technoserv. 2014. Vol. 1].

The measured values of the range and speed of the detected object are compared with a predetermined criterion. If, based on the measured values of the range and speed of the detected object, according to a predetermined criterion, a decision is made on the need to clarify the coordinates of the object, then from the m-th azimuthal position, the transmitting and receiving radiation patterns are moved by electronically scanning them to one of the k previous azimuthal positions, corresponding to the intended direction to the selected detected object, where k can take a value from 1 to m-1. In this position, the distance and elevation coordinates of the selected object are measured.

Next, the transmitting and receiving radiation patterns are moved by means of their electronic scanning to the azimuth position m+1 and the survey of space is continued by scanning the radiation pattern in azimuth.

The use in the proposed method of additional measurement of the coordinates of the selected object, for example, moving at high speed, allows you to perform more accurate tracking of objects than in the prototype, in which the coordinates are measured with a space scanning period, which can be several seconds, while during the review the coordinates of a high-speed object can change greatly before the review.

The use in the proposed method of more frequent measurement of the coordinates of the selected objects reduces the time of tying the route of these objects, compared with the prototype, in which the tying of the object's route is performed after several periods of space scanning.

The performance of the proposed method was tested on a mock-up device (Fig. 1). Tests showed the coincidence of the obtained characteristics with the calculated ones.

Claims (1)

A method for surveying space, in which the directional pattern is scanned in azimuth, while sequential data processing is performed in discrete time with reference to each azimuth position of the directional pattern, a digital antenna array is used to form the transmitting and receiving directional patterns, while in each azimuthal position of the directional pattern in the transmission mode, a transmitting fan-shaped radiation pattern is formed in the elevation plane; in the reception mode, the received reflected signals are presented in the form of digital readings, from which, by weighted summation, a receiving multipath radiation pattern is formed in the elevation plane, each beam of which has a needle shape, and adjacent rays overlap at the half power level, while the width of the receiving and transmitting radiation patterns corresponds to the angular size of the detection zone in the elevation plane, objects are detected, their angle is measured speed, range and elevation coordinates by a monopulse method for processing signals from each of the neighboring pairs of receiving beams having the same azimuth coordinate, characterized in that if, according to the measured values of the range and speed of the detected object, according to a predetermined criterion, a decision is made on the need to clarify the coordinates of the object, then from the m-th azimuth position, the transmitting and receiving radiation patterns are moved by electronically scanning them to one of the k previous azimuth positions corresponding to the intended direction to the selected detected object, where k can take a value from 1 to m-1, the range and elevation are measured coordinates of the selected object, after that, the transmitting and receiving radiation patterns are moved by electronically scanning them to the azimuth position m+1 and continue the survey of space by scanning the radiation pattern in azimuth.

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