The application of time-frequency analysis for extracting radar target in chaff-interference

The problem of extracting radar target from chaff-interference is investigated in this paper. The need for analysis of time varying signals has led to the formulation of a class of joint time-frequency distributions (TFDs). One of these TFDs, the Wigner-Ville distribution (WVD), has useful properties which can be applied to represent a linear signal space. The WVD of a signal space can be expressed in a simple way in terms of the space´s projection operator and bases. The analysis of time-frequency properties for both interference and target is discussed at first and then based on the theory of time-frequency (TF) filter and expansion. The method of designing TF pass region and its corresponding TF projection filter are pointed out to act on the radar return sampled in each pulse cycle. Computer simulation results show that this method has better performance in suppressing chaff-interference and can reconstruct the target signal in its original domain