Influence of migratory scattering phenomenon on micro-motion characteristics contained in radar signals

The micro-motion characteristics of radar target are useful features for target recognition. Extended targets (as opposed to point target) have various scattering centres, such as the familiar point, localised and distributed scattering centres, as well as the rarely discussed but often encountered migratory scattering centres. The migratory scattering phenomenon of smooth surface is particularly concerned in this study. The motion information recoded in radar signals are actually that of migratory scattering centres rather than the real motions of the rigid target. Therefore the misleading motion information will bring unpredictable error to the radar application of target discrimination or recognition. To tackle this problem, the influence of migratory scattering phenomena of extended targets on micro-motion characteristics contained in radar signal is analysed in detail. Some meaningful conclusions are reached. The backscattered signals of extended targets are computed by the well-validated fullwave numerical method, hybrid finite element-boundary integral-multilevel fast multipole algorithm. The numerical results agree well with the analytical conclusions given in this study.