Multi-cycle Integration of Weak Target Signals in LFMCW Radar

This paper presents a new way for integration and detection of weak signals with large Doppler frequency in linear frequency-modulated continuous wave (LFMCW) radar systems. With secondary mixing of up-sweep beat signal and down-sweep beat signal, the range-Doppler coupling can be resolved effectively, and a new signal with only Doppler frequency information is brought out. By two-dimensional FFT (Fast Fourier Transform), multi-cycle weak signals can be integrated to get high signal-to-noise ratio (SNR) for target detection and parameters estimation. Using peak detection, target velocity is estimated first. Motion compensation then follows according to the velocity estimated, and target range can be found out also through two-dimensional FFT. And performance analysis is carried out finally. The efficiency of the method is proved by the simulation results.