RU2007104325A - METHOD OF ACCOMPANYING THE PURPOSE AND DEVICE OF MONOPULSE RADAR REALIZING THE METHOD - Google Patents

Claims (5)

1. A method of tracking a target in a monopulse radar, including setting the RSN axis of a monopulse antenna in the direction of the intended target according to a previous review; emission of pulsed coherent signals in a given direction; receiving high-frequency signals in the interval between probing; sum-difference conversion of received signals, their superheterodyne conversion to an intermediate frequency; amplification of the sum and difference signals at an intermediate frequency; the conversion of signal spectra into the region of video frequencies by means of quadrature-phase detection using reference oscillations f _o , the frequency of which is equal to the intermediate frequency; consistent filtering of total and difference signals to obtain M-point time realizations of the analytical total v _∑ij and difference v _Δij signals for each j-th repetition period

in range

, multichannel Doppler filtering of the complex envelope of the pulse sequence of the total signal for each range element in a given interval in the Doppler frequency range from minus 1 / 2T _p to 1 / 2T _p with a band ΔF and the number of channels N = 1 / T _p ΔF, where T _p - probe pulse repetition period, ΔF is the width of the spectrum of inter-period fluctuations of signals from true targets Z _∑in = F (v _∑ij ), where i is the number of the range element, j is the number of the repetition period, n is the number of the Doppler filter,

, F is the Fourier transform operator; calculation of the amplitude of the spectral components of the total signal

; detection of signals for which P _∑in exceeds the detection threshold in the a priori range range,

, M _A ≤ M; search for the target signal with the spectrum width ΔF _D less than the threshold Δ _threshold , including the calculation of the spectral width ΔF _{D of the} total signal in decreasing order of their amplitudes in range, comparing the current calculated value of the spectral width ΔF _D with a given threshold value Δ _threshold , when it is exceeded, a decision is made about detection of a false target, cyclic repetition of the calculation of the spectrum width of the signal following the amplitude, until the target signal with the spectrum width is less than the threshold; determination of the number of the Doppler filter n _c with the maximum amplitude of the target spectrum; determining a frequency mismatch signal, closing the frequency tracking loop, adjusting the frequency mismatch signal to position n _{c the} tracking strobe in frequency; narrow-band filtering with a bandwidth ΔF = 1 / NT _{n of the} complex envelope of the pulse sequences of signals in the total and difference channels at the tracked n _C Doppler frequency with obtaining complex spectral components of the total Z _∑ (i, n _c ) and difference Z _Δ (i, n _c ) signals, the selection of the amplitude envelope of the signals in the total channel

, isolating the error signal by range in the total channel, closing the range tracking loop and adjusting the position (i _c ) of the range tracking gate with this signal, calculating the angular mismatch signal γ (i _c , n _c ) of the RSN relative to the direction to the target according to the calculation of the spectral components the total Z _∑ (i _c , n _c ) and differential Z _Δ (i _c , n _c ) signals at the tracked point in the scene, the range is the Doppler frequency (i _c , n _c ), the angle of the tracking contour is closed according to the angular error signal γ (i _c , n _c ) with correct by adjusting the position of the PCN of a single-pulse antenna, characterized in that, after quadrature-phase detection, the band of specular video frequencies is suppressed, where the target signal a priori there is no target signal shifted by the Doppler frequency, the actual total difference signals are digitized with a sampling frequency F _B exceeding the frequency band occupied by the modulating signal ΔF _c more than twice; before starting the search for the target signal after the threshold detection, the number of detected signals w is determined; if during the cyclic search of the target signal for w cycles the target signal is not detected, multichannel Doppler filtering of the total signals is performed in the frequency range from zero to 1 / 2T _p at ranges

where there are no reflected signals to obtain complex spectra of the total signals Z _∑in and the amplitudes of the spectral components of the total signal

, threshold detection of noise interference source signals by amplitudes P _{∑in of} spectral components that exceed the detection threshold of the noise source, finding N _e extreme points (i _e , n _e ) with a maximum amplitude of spectral component P _∑in , with the calculation of the difference spectral components for them signal Z _Δ (i, n), calculation of the RSN mismatch signal relative to the direction of the noise interference source γ _un as the average value of the angular mismatches γ _e for N _e extreme points (i _e , n _e ) by quadrature spec the sweeping components of the total Z _∑ (i _e , n _e ) and differential Z _Δ (i _e , n _e ) signals; short circuit of the tracking system in the angle with pointing the axis of the antenna according to the signal of the angular mismatch of the RSN antenna to the source of noise interference. 2. The method according to claim 1, characterized in that the suppression of the mirror video frequencies of the input signal is performed by converting the quadrature components of the input video signal to a new pair of signals, further shifted 90 ° relative to each other in the frequency band occupied by the modulation of the probe signal, and their subsequent addition . 3. The method according to claim 1, characterized in that the matched filtering in each repetition period is performed by a sequence of operations including the M-point Fourier transform of the sequences of complex numbers x _ij = u _{∑ij +} ju _Δij , the real part of which is equal to the digitized samples of the total signal u _{∑ ij} , and imaginary - to samples of the difference signal u _Δij , with obtaining M-point spectra Xmj = F (x _ij ),

, m is the frequency number of the spectral component, reconstruction of the spectra of the analytical total S _Σmj and difference S _Δmj , signals from the spectra X _mj , multiplication of the spectra of the analytical total and difference signals with the complex conjugate spectrum of the probe signal S * _m to obtain the spectra of the compressed signals V _∑mj = S _∑mj S * _m and V _Δmj = S _Δmj S * _m , the inverse M-point Fourier transform with obtaining for each j-th repetition period M-point analytical time realizations of the compressed total v _∑ij and difference v _Δij signals; 4. Monopulse radar that implements the method according to claim 1, contains a monopulse antenna system, the first input-output of which is connected to the second input-output of the antenna switch, a pathogen, quadrature-phase detectors of the total and difference channel, a synchronizer, characterized in that it is introduced transmitter, switch, serially connected modulated signal shaper, reference signal shaper and on-board computer (BTsVM), high-frequency receivers of total and difference signals, the first the odes of which are connected to the third output of the antenna switch and the output of the switch, respectively, the block for suppressing the mirror channel in the total channel, connected through the video amplifier of the total channel with the fourth input of the digital computer, the block for suppressing the mirror channel in the difference channel, connected through the video amplifier of the differential channel with the fifth input of the digital computer, this high-frequency receiver of the total signal through a quadrature-phase detector of the total signal is connected to the first input of the block suppression mirror channel in ummar channel, a high-frequency difference signal receiver through a quadrature-phase difference signal detector is connected to the first input of the mirror channel suppression unit in the difference channel, the first output of the exciter is connected to the second inputs of the high-frequency receivers of the total and difference signals, the first input of the transmitter, the third output of the exciter is connected to the first inputs of the driver of the reference signal, quadrature-phase detectors of the total and difference signals, the second outputs of which are connected with the same name the input inputs of the block suppression mirror channels of the total and differential channels, respectively, the first input-output of the BCMC is connected to the third inputs of the high-frequency receivers of the total and differential channels, the third input of the switch, the fourth input-output of the monopulse antenna system, the fourth input of the transmitter, the input of the exciter and the first input of the synchronizer , the second and third outputs of the monopulse antenna system are connected to the first and second inputs of the switch, the output of the driver of the modulated signal is connected inen with the third input of the transmitter, the second output of the synchronizer is connected to the inputs of the modulator and transmitter of the same name, the third output of the synchronizer is connected to the second inputs of the video amplifiers of the sum and difference channels, the second output of the driver is connected to the input of the synchronizer, the first output of which is connected to the same input of the modulator signal, the fourth output of the synchronizer is connected to the sixth input of the digital computer, the second input-output of which is the radar input-output. 5. Monopulse radar according to claim 4, characterized in that the mirror channel suppression unit contains two phase-shifting chains and an adder, the inputs of which are connected to the outputs of phase-shifting chains, the inputs of phase-shifting chains are quadrature inputs of the mirror-channel suppression unit, the adder output is the output of the mirror-suppression unit signal.