DOA estimation of multi-component LFM in complex environment using ESPRIT based on FRFT

Linear frequency modulation (LFM) signals are widely used in information systems. However, using traditional array signal process couldn't commendably estimate DOA of LFM signal, because which is a non-stationary signal. In this paper, the proposed method firstly applied the fractional Fourier Transform (FRFT) to construct the LFM signals array model, in which time-variant steering vector is changed into time-invariant one and wideband LFM signals are converted to narrowband stationary ones. Afterwards, a new improved ESPRIT method was proposed of DOA estimation which sufficiently made use of correlation and cross correlation information of covariance matrix to construct the new matrix. Then, the DOAs of coherent and non-coherent LFM signals are estimated by the signal parameters via a new improved rotation invariance technique (ESPRIT). Simulation results can not only demonstrate the effectiveness of this method, but also achieve high estimation accuracy.