Positive and negative slope LFM waveform orthogonal polarization radar-based anti-shift frequency interference method

Abstract

The invention discloses a positive and negative slope LFM waveform orthogonal polarization radar-based anti-shift frequency interference method. The method includes the following steps that: (1) an orthogonal dual-polarization radar transmits signals in a positive and negative slope LFM waveform form, receives echo sequences, carries out matched filtering and normalization on the sequences so as to obtain the output sequences of an HH channel, an HV channel, a VH channel and a VV channel, and carries out time-domain reversal on the output sequence of the HV channel and the output sequence of the VV channel; (2) the output sequences of the four channels are processed, so that a sequence 1 can be obtained; (3) target detection is carried out on the sequence 1, so that target positions to be determined are obtained, a sequence 2 is extracted from the sequence 1; (4) the output sequences of the four channels are processed according to the target positions to be determined, so that a sequence 3 can be obtained through extraction; (5) the ratio of the sequence 3 to the sequence 2 is calculated and is adopted as an identification quantity; and (6) the identification quantity is compared with a threshold value, so that a target and frequency shift interference can be judged. According to the method of the invention, processing of signals which have been subjected to matched filtering does not involve complex operation, and therefore, the method has high real-time performance.

Description

technical field [0001] The invention belongs to the field of electronic investigation and relates to an anti-frequency shifting interference method based on positive and negative slope LFM waveform orthogonal polarization radar. Background technique [0002] Frequency shift jamming is an effective means to deal with linear frequency modulation (LFM) pulse compression radar at present. Due to the range-Doppler frequency shift coupling phenomenon in the ambiguity function of the chirp pulse compression radar signal, the interaction between the range and the Doppler frequency shift will make the Doppler mismatch between the target and the matched filter , the estimation of the distance will also produce a certain error. The research on anti-frequency shift interference is currently mainly focused on the use of time-varying transmission signals, such as changing the frequency modulation slope and initial phase of the transmission signal, but this method will increase the diffic...

AI Technical Summary

Problems solved by technology

Due to the range-Doppler frequency shift coupling phenomenon in the ambiguity function of the LFM pulse compression radar signal, the interaction between the range and the Doppler frequency shift will make the Doppler mismatch between the target and the matched filter , there will be some error in the estimation of the distance

The research on anti-frequency shift interference is currently mainly focused on the use of time-varying transmission signals, such as changing the frequency modulation slope and initial phase of the transmission signal, but this method will increase the difficulty of the transmitter

In addition, the time-frequency analysis method can also be used, but the requirements for the signal-to-noise ratio are relatively high, and signal aliasing may occur

The above methods require a considerable amount of calculation, and cannot guarantee the real-time performance of target detection.

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