Contents I. Introduction
Miss distance (MD) is defined as the minimum distance between a guided flying object and its intended target site during their intersection [1], [2]. MD estimation is one of the significant performance tests for guided flying objects. In order to measure MD, the intended target site is substituted by a measuring radar, and from the received signals by the radar, MD can be estimated by signal processing and parameter estimating. The traditional MD estimation method is based on the Doppler effect induced by the relative motion between the object and the measuring radar. Doppler frequencies in every time bin are extracted from time-frequency representations (TFRs) of the received signals through peak searching or centroid extracting [3], then MD is estimated through the curve fitting of the extracted Doppler frequencies with a parametric model based on an ideal scatterer. Considering that wild values always arise due to the noise, additional smoothing processes [4] are commonly combined with the fitting process to eliminate the influence of wild values.
