RU2602072C1 - Passive coherent radar system of decametre range - Google Patents

Abstract

FIELD: radar ranging and radio navigation.

SUBSTANCE: invention relates to passive radar systems. Technical result is achieved by using, including, n-channel antenna amplifier with switched subbands of subassembly 1, channel-forming unit of subassembly 2, n-element phased antenna array of subassembly 2, n-channel receiver of subassembly 2, n-channel unit of adaptive filters of subassembly.

EFFECT: technical result is improved target detection range and accuracy.

1 cl, 3 dwg

Description

The first passive radar was created in 1937 in the UK (N.J. Willis. Bistatic Radar, volume 8. Sci Tech Publishing, 2005). The Air Force broadcast transmitter was used as a backlight source. Between the broadcast transmitter and the passive radar was a ridge screening the direct signal of the transmitter. The broadcast transmitter signal was reflected from the aircraft and received by a passive radar antenna. A passive radar device (NJ Willis. Bistatic Radar, volume 8. Sci Tech Publishing, 2005), which is a superheterodyne receiver, contained an antenna, a radio frequency filter, a radio frequency amplifier, a mixer, an intermediate frequency filter, an intermediate frequency amplifier, a radar detector and indicator - in in this case, headphones. The block diagram of a passive radar is shown in FIG. 1, on which the following notation is used: 1 - antenna, 2 - radio frequency filter, 3 - radio frequency amplifier, 4 - mixer, 5 - intermediate frequency filter, 6 - intermediate frequency amplifier, 7 - detector, 8 - headphones, 9 - local oscillator .

The successful results of these experiments marked the beginning of the development of radar.

Closest to the claimed device is "Passive radar system" - Patent RU No. 71781, IPC classes: G01S 17/00, G01V 5/12.

The device "Passive radar complex" - Patent RU No. 71781, IPC classes: G01S 17/00, G01V 5/12, the structural diagram of which is shown in FIG. 2, consists of an antenna system 10, a multi-channel receiver 11, a beamforming unit 12, an adaptive filter unit 13, a moving target selection unit 14, a path tracking unit 15, an indicator 16, a first coupler 17, a discrete frequency generator 18, a clock generator 19, a second coupler 20 , an operating frequency selection unit 21, an antenna control unit 22.

The device "Passive radar complex" - Patent RU No. 71781, IPC classes: G01S 17/00, G01V 5/12, relates to the field of passive radar systems. Passive decameter range radars are not inferior in effectiveness to space-based surveillance and monitoring equipment, and by the criterion "Efficiency / Cost" they are tens of thousands of times superior.

Passive radar system is designed to determine the coordinates of the location of objects, in particular marine vessels. The passive radar complex can use any broadcasting signals with and without modulation of the KB range to illuminate objects. Passive radars do not emit a signal on the air, so they are invisible to electronic intelligence equipment. Receiving antennas are made in the form of a linear array of compact antenna elements forming the system of the desired configuration.

Passive radar system works as follows. The antenna system (10) is made in the form of a linear array of compact antenna elements forming the system of the desired configuration.

The signals from the outputs of the antenna system (10) are fed to the inputs of a multi-channel receiver (11), all channels of which are tuned to one operating frequency. Received signals are amplified, converted to a low intermediate frequency.

The output signals of the multichannel receiver (11) enter the beamforming unit (12), which forms a multi-beam radiation pattern. Block (12) is a matrix of digital phase shifters.

The signals from the outputs of the beamforming unit (12) are fed to the inputs of the adaptive filter unit (13), in which they undergo narrow-band frequency filtering in the Doppler frequency band, determined by the range of target speeds and the operating frequency.

Adaptive filter blocks (13) in the channel of each of the beams carry out angular rejection - suppression of the probing broadcasting signal. Moving targets are highlighted by a block of moving targets selection (14). At this processing stage, targets are selected with an estimate of their current coordinates based on interpolation in the azimuth-range space using smoothing by the type of processing path in the path tracking block (15). The display of radar information is provided on the indicator (16).

In the device "Passive radar complex" - Patent RU No. 71781, IPC classes: G01S 17/00, G01V 5/12, using the selection of the operating frequency (21), the optimal operating frequency is selected. Using the antenna control unit (22), the antenna system (10) is controlled.

Thus, the prototype — a passive radar system — contains an antenna system (10) made of antenna elements whose outputs are connected to the inputs of the corresponding channels of the multi-channel receiver (11), the outputs of which are connected to the inputs of the beam forming unit (12), the outputs of the beam forming unit are connected to the corresponding inputs of the adaptive filter unit (13), the outputs of the adaptive filter unit (13) are connected to the inputs of the moving targets selection unit (14), the first output of which is connected to the unit input path tracking (15), and the second to the first input of the indicator (16), the second input of which is connected to the first output of the trajectory tracking unit, and the second output of the trajectory tracking unit (15) is connected to the control input of the antenna control unit (22), the first output which is connected to the antenna system (10), and the second output is connected to the input of the operating frequency selection unit (21), the output of the working frequency selection unit (21) is connected to the second inputs of the channels of the multi-channel receiver (11), also contains the first (17) and second (20) splitters, outputs of the second splitter (20) are connected to the second inputs of the adaptive filter unit (13), and the input is connected to the output of the discrete frequency generator (18), the outputs of which are connected to the input of the synchronizer (19), the outputs of which are connected to the inputs of the second splitter (20) and the first splitter ( 17).

The disadvantages of this device is the insufficient range and accuracy of target detection, limited by the signal-to-noise ratio.

To overcome this drawback allows the inter-correlation reception of signals spaced in space.

To increase the range and accuracy of target detection using the inter-correlation reception of signals spaced in space, the following device is proposed, the structural diagram of which is shown in FIG. 3, comprising a serially connected n-element phased antenna array of half-set 1 (23), an n-channel antenna amplifier with switchable subbands of half-set 1 (24), an n-channel receiver of half-set 1 (25), a diagram-forming block of half-set 1 (26), n-channel block of adaptive filters of half-set 1 (27), n × n-matrix of correlators (28), target detection block (37), tracing block (38) and indication block (39), also containing a series-connected n-element phased antenna half-set grating 2 (29), n-channel antenna amplifier with switchable subbands of half-set 2 (30), n-channel receiver of half-set 2 (31), diagram-forming block of half-set 2 (32), n-channel block of adaptive filters of half-set 2 (33), channel-forming block of half-set 2 (34), a communication channel (35), a channel-forming unit of the half-set 1 (36), as well as a series-connected control antenna (40) and an operating frequency selection unit (41), while the sub-band switching output of the operating frequency selection unit (41) is connected to sub-band switching inputs n -channel an antenna amplifier with switchable subbands of the half-set 2 (30) and the channel-forming block of the half-set 2 (34), the tuning control output is connected by the tuning control codes of the n-channel receiver of the half-set 2 (31) and the channel-forming block of the half-set 2 (34), the outputs of the signals received by the half-set 2 the half-set unit 1 (36) are connected to the corresponding inputs of the n × n-matrix of correlators (28), the subband switching output of the channel-forming block of the half-set 1 (36) is connected to the corresponding n-channel input antenna amplifier with switchable subbands of half-set 1 (24), and the control output of the channel-forming unit of half-set 1 (36) is connected to the corresponding input of the n-channel receiver of half-set 1 (25).

Moreover, the cross-correlation reception of more than 3 dB improves the signal-to-noise ratio. Thus, the following device is proposed.

A device is proposed (Fig. 3) - a decameter range passive coherent radar system containing a serially connected n-element phased antenna array of half-set 1 (23), an n-channel antenna amplifier with switchable subbands of half-set 1 (24), an n-channel half-set receiver 1 (25), diagram-forming block of half-set 1 (26), n-channel block of adaptive filters of half-set 1 (27), n × n-matrix of correlators (28), target detection block (37), tracing block (38) and indication block (39), also holding a serially connected n-element phased antenna array of half-set 2 (29), an n-channel antenna amplifier with switchable subbands of half-set 2 (30), an n-channel receiver of half-set 2 (31), a beam-forming block of half-set 2 (32), n- channel block adaptive filters of the half-set 2 (33), channel-forming block of the half-set 2 (34), a communication channel (35), channel-forming block of the half-set 1 (36), as well as a series-connected control antenna (40) and the operating frequency selection unit (41), at the same time switching output sub-bands of the operating frequency selection block (41) is connected to the switching inputs of the subbands of the n-channel antenna amplifier with switchable subbands of the half-set 2 (30) and the channel-forming block of the half-set 2 (34), the tuning control output of the working frequency selection block (41) is connected to the tuning control inputs of the n-channel receiver of the half-set 2 (25) and the channel-forming block of the half-set 2 (34), the outputs of the signals received by the half-set of 2 signals of the channel-forming block of the half-set 1 (36) are connected to the corresponding n × n inputs correlators (28), the sub-band switching output of the channel-forming block of half-set 1 (36) is connected to the corresponding input of the n-channel antenna amplifier with the switched sub-bands of half-set 1 (24), and the control output of the channel-forming block of half-set 1 (36) is connected to the corresponding input n channel receiver half-set 1 (25).

The principal feature of the proposed device from the prototype is the presence of two half-sets of passive coherent radar complex decameter range, spaced in space.

The fundamental difference between the proposed device and the prototype are the n-channel antenna amplifier included in the device with switchable subbands of half-set 1 (24), the n-element phased array antenna array of half-set 2 (29), the n-channel antenna amplifier with switchable subbands of half-set 2 ( 30), n-channel receiver of half-set 2 (31), diagram-forming block of half-set 2 (32), n-channel block of adaptive filters of half-set 2 (33), channel-forming block of half-set 2 (34), channel communication (35), the channel-forming unit of half-set 1 (36), as well as the n × n-matrix of correlators (28) and the control antenna (40), while the output of the switching of the subbands of the operating frequency selection unit (41) is connected to the switching inputs of the subbands n- channel antenna amplifier with switchable subbands of half-set 2 (30) and channel-forming block of half-set 2 (34), the output of the tuning control unit for selecting the operating frequency (41) is connected to the control inputs of the n-channel receiver of half-set 2 (31) and the channel-forming block half 2 (34), the signal outputs of the channel-forming block of half-set 1 (36), as well as the outputs of the n-channel block of adaptive filters of half-set 1 (27), are connected to the corresponding inputs of the n × n-matrix of correlators (28), the output of the switching of subbands the channel-forming unit of half-set 1 (36) is connected to the corresponding input of the n-channel antenna amplifier with switchable subbands of the half-set 1 (24), and the output of the tuning control channel of the channel-forming unit of half-set 1 (36) is connected to the corresponding input of the n-channel receiver and half-set 1 (25).

To increase the range and accuracy of target detection by a decameter passive coherent radar system, the device includes an n-channel antenna amplifier with switchable subbands of half-set 1 (24), a channel-forming block of half-set 2 (34), an n-element phased antenna-array of half-set 2 ( 29), an n-channel antenna amplifier with switchable sub-bands of half-set 2 (30), an n-channel receiver of half-set 2 (31), a diagram-forming block of half-set 2 (32), an n-channel adaptive block Filtering two half-sets (33), half-sets channelization block 2 (34), the communication channel (35), half-sets channelization block 1 (36), the control antenna (40) and the n × n-matrix correlators (28).

The decameter passive coherent radar system operates in the entire decameter range of 5-15 MHz. Powerful radio broadcasting stations are used to illuminate targets. However, it is practically impossible to create an antenna amplifier with such a band, flat frequency response, and linear phase response.

But this is not required, since broadcasting is carried out in narrow subbands.

Therefore, the antenna amplifier must have switchable subbands (24) and (30). Switching is controlled by the operating frequency selection unit (41), which selects radio stations with the best signal-to-noise ratio at the receiving point. The same unit controls the tuning of the receivers of the passive coherent radar complex of the decameter range (25) and (31).

The entire passive coherent radar complex of the decameter range consists of two half-sets, spaced in space by a distance much greater than the wavelength of the signal connected by a communication channel. The combination of half-sets is carried out using a series-connected communication channel (35), the channel-forming block of the half-set 1 (36) and the channel-forming block of the half-set 2 (34).

Cross-correlation of signals spaced in space is realized in the n × n-matrix of correlators (28).

The layout of the device in accordance with the patent application is assembled and tested by the authors, which proves the feasibility of the proposed device.

References

1. N.J. Willis. Bistatic Radar, volume 8. Sci Tech Publishing, 2005.

2. "Passive radar system" - Patent RU No. 71781, IPC classes: G01S 17/00, G01V 5/12.

Claims (1)

Passive coherent radar complex of decameter range, containing serially connected n-element phased antenna array of half-set 1, n-channel antenna amplifier with switchable subbands of half-set 1, n-channel receiver of half-set 1, diagram-forming block of half-set 1, n-channel block of adaptive half-set filters 1, n × n matrix of correlators, a target detection unit, a tracing unit, and an indication unit also comprising serially connected n-element phasi antenna antenna array of half-set 2, n-channel antenna amplifier with switchable subbands of half-set 2, n-channel receiver of half-set 2, diagram-forming block of half-set 2, n-channel adaptive filter block of half-set 2, channel-forming block of half-set 2, communication channel, channel-forming half-set block 1, as well as a series-connected control antenna and an operating frequency selection unit, wherein the sub-band switching output of the operating frequency selection unit is connected to sub-range switching inputs the azones of the n-channel antenna amplifier with switchable subbands of the half-set 2 and the channel-forming block of the half-set 2, the tuning control output is connected by the tuning control codes of the n-channel receiver of the half-set 2 and the channel-forming block of the half-set 2, the outputs of the signals received by the half-set 2 of the signals of the channel-forming block of the half-set 1 are connected to the corresponding inputs n × n-matrix correlators, the switching output of the subbands of the channel-forming block of the half-set 1 is connected to the corresponding input of the n-channel nogo antenna amplifier with switchable half-sets subbands 1 and the control output adjustment unit channelization half-sets 1 is connected to a corresponding input n-channel receiver 1 half-sets.

Images