2-D DOA estimation of LFM signal based on FRFT

Linear frequency modulation (LFM or chirp) signals are widely used in information systems, how to detect and estimate LFM signals is an important problem. However, using traditional array signal process couldn't commendably estimate DOA of LFM signal, because which is a nonstationary signal. Aim at this problem, the paper combined array signal process and fractional Fourier transform (FRFT), proposed extracting signal from the mixture of sources and noise using time-frequency revolving characteristic of FRFT. Then obtained unambiguous initial frequency and frequency modulation slope estimates from the output of the reference element, while combining music arithmetic to estimate 2-D DOA. This paper puts forward a new technique for LFM signal process, which has practical applied importance.