Abstract:

In inverse synthetic aperture radar (ISAR) imaging, when targets have nonuniform rotation even threedimensional rotation, the high order phase term which influences azimuth focusing badly can not be neglected. In this condition, the rangeDoppler (RD) algorithm is not a very effective way for ISAR imaging. A new imaging method based on product highorder phase function (PHPF) is presented. By searching the position of maximum magnitude of PHPF, the chirp rate and quadratic chip rate are gotten. Furthermore, fast Fourier transform (FFT) is performed after compensating the high order phase term to acquire the information about the center frequency and magnitude of these scatters according to the criterion of maximum magnitude. Thus the high quality rangeinstantaneous Doppler (RID) and rangeinstantaneous chirp rate (RIC) ISAR images of the target are obtained, so more information of targets can be gotten. Finally, the imaging results of real data prove the effectiveness of the proposed method.