Estimation of target circumferential size by backscattered wave

Most of target identification methods compare information of the backscattered field with an existing lookup table. Therefore, the identification of targets outside the table is impossible. However, by applying proper signal processing algorithms, some information about the target can be deduced. In this study, a new approach to estimate the circumferential size of radar targets, without their identification, is proposed on the base of a transient scattered field. Scattered transient response from the target consists of two parts: early time and late time. The early-time response corresponds to direct reflection and the late time is related to oscillation phenomena corresponding to surface-creeping waves and cavity waves. The time difference between the the start of early time and late time responses corresponds to a time interval in which creeping wave travels the geodesics surface path of the target. Therefore, by calculating the time difference between these two successive parts of response, the circumferential size of the target can be estimated. The start time of these two parts is determined by the matrix pencil method. In this study, the circumferential sizes of various simple targets such as cylinder, disc, cube, and a complex object, with an estimation error of