Iterative angle-and-time-domain gating technique for time-reversal MUSIC imaging

• Angle-and-time-domain gating for time-reversal (TR) MUSIC imaging is proposed.
• The two-dimensional technique works iteratively and complementarily.
• The technique reduces the number of targets to be detected at one time.
• The technique also decreases the effect of noise.
• It improves the imaging performance of TR-MUSIC.

This study develops the preprocessing theory for time-reversal multiple signal classification (TR-MUSIC) imaging from the one-dimensional (time-domain) gating proposed in earlier papers to a two-dimensional one. Although the one-dimensional gating technique for TR-MUSIC mitigates the effect of noise as well as reduces the required number of antenna elements, the resulting image is subject to focusing errors when there are many targets in the gated region. In this paper, we propose a two-dimensional (angle-and-time-domain) gating technique based on the fast Fourier transform (FFT) and spatial FFT processing. By using these transforms and gating iteratively, we can reduce the number of targets to be detected at one time. The TR-MUSIC technique for the gated data provides more reliable images and precisely estimated coordinates compared with the previous work.