Joint estimation of moving target reflectivity and velocity via AT-InSAR systems based on complex interferometric data

In this paper a technique for the joint estimation of the complex reflectivity and of the radial velocity of ground moving targets, by means of Along-Track Interferometric Synthetic Aperture Radar (AT-InSAR) systems, is presented. It is essentially based on statistical estimation techniques and exploits the complex interferometric SAR images, contrarily to other conventional AT-InSAR methods, which estimate the target radial velocity exploiting only the interferometric phases. The performances of the method are evaluated both for single baseline and for dual-baseline satellite systems, in terms of Cramer Rao Lower Bounds and of Root Mean Square Errors obtained in numerical experiments, with reference to all the target parameters to be estimated, which are the amplitude and phase of the target reflectivity and the target radial velocity. It is shown that for single baseline systems the obtained radial velocity estimation accuracy is comparable with the one achievable with AT-InSAR methods exploiting phase-only data, and is very high for high values of signal to clutter ratio. For dual-baseline systems, instead, the use of amplitude and phase data allows a performance significantly better than the one achievable exploiting phase-only data. Moreover, in the dual baseline case, high velocity estimation accuracy can be obtained also with lower signal to clutter ratios.