Frequency Agile LFMCW Radar Signal Design And Analysis

The electromagnetic environment of modern battlefield is complex,which requires high anti-jamming performance of detection system.Frequency agility is a technology with strong anti-jamming ability.In this thesis,aiming at the anti-jamming requirement of short-range detection application,the frequency agility sequence generation,signal processing method and anti-jamming performance of frequency agility LFMCW radar are studied.The contents are summarized as follows:1)Because of the problem of radar anti-enemy jamming and mutual jamming between our radars,the chaotic frequency hopping sequence is proposed as the frequency agile sequence used in frequency agile LFMCW radar.Chaotic sequence is not easy to be decoded,which makes frequency agile LFMCW have a strong anti-jamming ability.However,the chaotic sequence generated by FPGA will reduce the linear complexity,balance and Hamming correlation of chaotic sequence due to the limitation of limited precision.Considering the generation time of frequency agile sequence,a variety of performance is selected.The better chaotic frequency hopping sequence is applied to frequency agile LFMCW radar.2)Based on the problem that Doppler frequency is not fixed value caused by frequency agile LFMCW radar because of frequency hopping of FM center frequency,and the need of ranging detection with high anti-jamming performance,a signal processing method of multi-frequency information shunting-fusion is proposed to ranging targets;and based on the need of ranging and velocity detection with high real-time requirement,a signal processing method based on differential-frequency-dimension FFT-Doppler correlation accumulation is proposed for target ranging and velocity measurement,and a signal processing method based on differential-frequency-dimension CZT-Doppler compensation correlation accumulation is proposed for target ranging and velocity measurement.3)According to the research of anti-active jamming performance of frequency-agile LFMCW and several typical active jamming models,the simulation results show that the anti-active performance of frequency-agile LFMCW radar is better than that of general LFMCW radar,especially against range deception false target jamming,compared with the anti-active performance of general LFMCW radar.