Ultrahigh Range Resolution ISAR Processing by Using KT–TCS Algorithm

Nowadays, the slant-range resolution of inverse synthetic aperture radar (ISAR) can be improved to 1.5 cm by the application of microwave photonics technology. With the great improvement in range resolution, the ISAR images may contain more information on targets. However, ultrahigh resolution also induces severer space-variant range cell migration (RCM). In this paper, we propose an algorithm based on Keystone transform (KT) and time-domain chirp scaling (TCS) to deal with the space-variant RCM in ISAR imaging with ultrahigh range resolution. The algorithm consists of two steps. In the first step, the azimuth-variant linear components in the space-variant RCM are compensated for by KT. In the second step, the TCS is performed to remove the range-variant quadratic RCM. The results acquired from the processing of both the simulation and the real data validate the effectiveness of the proposed algorithm.