CN101231339A - Method for implementing uniform period repetition phase encoding continuous-wave radar diversity impulse - Google Patents

Abstract

The invention relates to a method for phase encoding in uniform repetition period of continuous-wave radar with staggered pulse. By utilizing the periodic cycle feature of phase encoded continuous-wave radar signals, multi-pass matched filter banks with different phase offsets can finish pulse compression, and the multi-path output signals after pulse compression can be selected by a selector to form a signal sequence with staggered periodic repetition. The phase encoded continuous-wave radar signals with uniform repetition period of T received by a receiver (1) are sent to N-path matched filters (2) for N-path matched filtering, the N-path pulse compression signals after N-path matched filtering sequentially select the outputs of the matched filters via a selector (3) to form a signal sequence output with staggered periodic repetition. The staggered periodic repetition sequence can increase the first blind speed via a MTI filter and improve the clutter suppression performance of the phase encoded continuous-wave radar.

Description

The uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method

Technical field

The present invention relates to the moving target display technique in the target detection field, be specifically related to the phase encoding continuous wave radar and utilize diversity impulse to postpone the implementation method of blind speed.

Background technology

Low probability of intercept probability radar is one of development trend of modern radar, the phase encoding continuous wave radar is exactly wherein a kind of, and it has minimum peak power and power spectrum density, in conjunction with the phase encoding pulse compress technique, can realize the target detection of long-distance, and be difficult for being found by investigation.

Find that under strong clutter environment moving target is one of function of modern radar indispensability, and clutter to suppress one of effective method be exactly that moving-target shows (MTI) technology.For the phase encoding continuous wave radar, in order to cover bigger scope, usually adopt low repetition period phase-coded signal, first blind speed of MTI is very low, therefore covering requirement can not be satisfied, just the MTI reliably working can be made more than must taking measures first blind speed raised the possible speed of target velocity to moving target.

The method that raises blind speed mainly contains two kinds, and a kind of is the repetition period of improving detectable signal, but this and raising detection range contradiction.Another adopts irregular repetition period method exactly, promptly adopts the different phase encoding repetition periods.But also there are contradiction in this and pulse compression and MTI, because each repetition period difference can not utilize the cycle auto-correlation to finish pulse compression, and each periodic signal energy difference can not directly use MTI to handle.

Summary of the invention

Technical matters: the object of the invention is to provide a kind of uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method, makes even repetition period phase encoding continuous wave signal produce the irregular cycle repetition methods of equivalence, thereby raises first blind speed.

Technical scheme: for realizing above-mentioned target, uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method of the present invention adopts following technical scheme: the even repetition period that receiver is received is that the phase encoding continuous wave radar signal of T is sent into N road matched filter and carried out the matched filtering of N road, N road pulse compression signal after the matched filtering of N road is selected the output of matched filter successively through a selector switch, constitutes to have the burst output that the irregular cycle repeats.

Codeword sequence behind described matched filter and the phase encoding continuous wave radar signal code word sequence cyclic shift is complementary, and phase encoding continuous wave radar signal codeword sequence is through ring shift P _iObtaining phase deviation after the individual code element is P _iThe ring shift codeword sequence, the corresponding displaced time dt of institute _i, N road matched filter is matched with different ring shift codeword sequences.

Behind the matched filter of same phase encoding continuous wave radar signal process N road, the N road pulse compression signal peak value of output does not overlap in time, and the time interval that peak value occurs is shift time dt _i

Beneficial effect: uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method disclosed by the invention, can produce the irregular effect of equivalent pulse, solve first blind speed and raised problem, improved the phase encoding continuous wave radar detects moving target in strong clutter environment ability.

Description of drawings

Fig. 1 is a uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method block diagram.

Fig. 2 is the irregular cycle repeating signal sequence of the pulse compression output and the selector switch output of out of phase skew matched filter.

Fig. 3 repeats the example of pulse pressure burst for the three irregular cycles of realizing.

Have among the above figure: receiver 1, matched filter 2, selector switch 3.

Embodiment

Fig. 1 is the adoptable theory diagram of realization the present invention, and receiver 1 export target echo is to be phase encoding baseband I/Q signal of T the repetition period among the figure, and this signal is divided into the N road, finishes the pulse compression of target echo in the matched filter 21～2N of N road.Matched filter 21～2N be designed to the phase-coded signal ring shift after codeword sequence be complementary, N road matched filter is matched with different codeword sequences, phase deviation is P between the codeword sequence of the relative i of i+1 road matched filter road matched filter _i(i=1,2 ..., N-1), phase deviation is P between the codeword sequence of the relative N of the No. 1 matched filter road matched filter _N, phase deviation P _iCorresponding shift time is dt _iBehind same phase encoding echoed signal process matched filter 21～2N, the N road pulse compression signal peak value of output does not overlap in time, and its time interval is shift time dt _iShift time dt _iCan be that positive number can be a negative also, satisfy constraint condition: $\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{dt}}_i=0,$ As shown in Figure 2.Selector switch 3 selects one method selection N road pulse compression output signal according to N, promptly constitutes to have the burst that the irregular cycle repeats, and its irregular ratio is (T+dt ₁): (T+dt ₂): ...: (T+dt _N).

Embodiment of the invention signal waveform as shown in Figure 3, this obtains at N=3, it has realized that even repetition period phase encoding continuous wave signal produces equivalence three irregular cycle repetitive sequences.The same repetition period is that the relative matched filter 21 of pulse compression signal peak value that the phase encoding continuous wave signal of T is exported through matched filter 22 has time-delay dt ₁(being negative in this example), the relative matched filter 22 of pulse compression signal peak value of matched filter 23 outputs has time-delay dt ₂(in this example for just), the relative matched filter 23 of pulse compression signal peak value of matched filter 21 outputs has time-delay dt ₃(in this example for negative) observes for convenience, and the output of three matched filters is drawn on same the figure.Selector switch 3 selects one method selection matched filter output according to three, promptly constitutes the diversity impulse sequence, and its irregular ratio is (T+dt ₁): (T+dt ₂): (T+dt ₃), as shown in Figure 3.

Claims (3)

1. uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method, it is characterized in that to the even repetition period that receiver (1) receives being that the phase encoding continuous wave radar signal of T is sent into N road matched filter (2) and carried out the matched filtering of N road, N road pulse compression signal after the matched filtering of N road is selected the output of matched filter successively through a selector switch (3), constitutes to have the burst output that the irregular cycle repeats.

2. uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method as claimed in claim 1, it is characterized in that the codeword sequence behind described matched filter (2) and the phase encoding continuous wave radar signal code word sequence cyclic shift is complementary, phase encoding continuous wave radar signal codeword sequence is through ring shift P _iObtaining phase deviation after the individual code element is P _iThe ring shift codeword sequence, the corresponding displaced time dt of institute _i, N road matched filter (2) is matched with different ring shift codeword sequences.

3. uniform period repetition phase encoding continuous-wave radar diversity impulse implementation method as claimed in claim 1, after it is characterized in that same phase encoding continuous wave radar signal is through N road matched filter (2), the N road pulse compression signal peak value of output does not overlap in time, and the time interval that peak value occurs is shift time dt _i

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