DOA estimation for low angle targets using time reversal in frequency domain model
Published in 2018 IEEE Radar Conference (RadarConf), 2018
Xiaolu Zeng, Baixiao Chen, Minglei Yang., RadarConf., Oklahoma City, OK, Apr. 2018.
Abstract
Multipath distortion has been a challenge problem for low angle target localization problem using very high frequency (VHF) radar. In particular, under complex terrain, part of the multipath lies in the same beamwidth of the direct path signal, which makes it difficult to be distinguished in the spatial, temporal and Doppler domains. This paper uses time reversal (TR) technique to adjust the transmitting signal waveform by exploring the channel information contained in multipath clutters. According to TR principle, this specially designed signal can refocus at the original target position, which not only mitigates the multipath distortion but also equally increases the signal-to noise ratio (SNR) of the TR receiving signal. Next, we analyzes the independence between the noise subspace and the sampling frequency bin in our TR wideband signal model. A novel direction of arrival (DOA) estimation method is then investigated in frequency domain. Compared with conventional methods, its superiority in DOA estimation accuracy for low angle targets is validated by numerical simulations.
Key Words: Time Reversal, DOA Estimations, Frequency Domain, Multipath