The rotational phase component (RPC) of target’s prominent scattering centers may affect the performance of Doppler centroid tracking (DCT) seriously in the inverse synthetic aperture radar (ISAR) autofocusing.Based on a unified ISAR scattering signal model
this paper introduces the concept of induced angle to evaluate the effect of RPC
and the factors affecting the induced angle are also analyzed.It is proved that the performance of DCT may be improved with the increase of radar pulse repetition frequency
and it is also shown that two improved DCT methods
i.e.circular shifting based DCT (CS-DCT) and image equilibrium based DCT (IE-DCT) are equivalent in principle.At last
numerical experiments are also provided to verify the effectiveness of the above performance analysis.