Review of Interferometric ISAR Imaging

Interferometric inverse synthetic aperture radar (InISAR) imaging is a recently developed radar three-dimensional (3-D) imaging method, which combines the interferometric technique and the inverse synthetic aperture radar (ISAR) processing. InISAR is able to carry out 3-D imaging of a far field moving target under all-weather condition and any required time, so it has shown a wide range of prospects and practical value in the field of military and civilian applications. The interferometric ISAR imaging requires a radar system with at least two receiving antennas spatial-separately employed to observe the target from different aspects. The echoes from the target are received by the two receivers and are processed respectively to obtain two-dimensional (2-D) images via the conventional ISAR processing. The azimuth or height information is then obtained from the phase differences of corresponding pixels in different ISAR images. This paper begins with an investigation of the InISAR imaging principle, followed by the development history and current status of InISAR imaging. The primary technique problems such as image registration, phase unwrapping, motion compensation, squint effect, baseline scheme and so on are particularly addressed. Moreover, the existing problems that need further research are pointed out. In the end, some current challenges and future trends are summed up and predicted.