A root-music algorithm for high resolution ISAR imaging

Inverse Synthetic Aperture Radar (ISAR) is used to image objects such as aircrafts and ships by the virtue of their rotation. The high resolution in range is obtained by large bandwidth pulses and similarly in the azimuth, by the rotational motion of the object. The rotational motion produces a Doppler shift, measured by the phase shift produced on a sequence of coherent pulses. Hence the azimuth resolution is determined by the Doppler discrimination using spectral analysis. In this paper, we propose an analysis technique for classification of ships, based on root-Multiple Signal Classification (MUSIC) algorithm, which betters the performance provided by the conventional Fast Fourier Transform (FFT) technique for ISAR imaging. This technique belongs to a class of super-resolution algorithms which also provides a resolution improved target classification.