Micro-doppler signal estimation for vibrating and rotating targets

Abstract

Vibrations or rotations of a target or structures on a target give rise to the micro-Doppler effect of the reflected waveforms. In this paper, we analyze micro- Doppler signals in the joint time-frequency plane using commonly applied distributions and time-frequency transforms. Performance is evaluated based on achieved resolution and reduced artifacts. The latter is significant in microDoppler analysis, as the signals have sinusoidal timefrequency (TF) signatures. This presents a challenge for the already established distributions, as they have to suppress the cross as well as the auto artifacts. We propose a new decomposition of basis functions, given the apriori knowledge of the time varying nature of the radar returns. This approach can be cast as an application of waveform diversity. The new decomposition is free from any artifacts and provides improved estimates of the target micro-Doppler signature.