A new method for SAR interferometric baseline rectification

Abstract

Interferometric SAR is an emerging earth observation technique, especially useful in cartography and surface subsidence survey, Differential SAR Interferometry (DInSAR) provides an alternative and complementary method to investigate the land subsidence phenomena, which can provide two dimensional deformations on the line of sight (LOS) of radar on areas of thousands square kilometers. In order to obtain accurate surface subsidence, precise orbit must be provided so as to compensate the reference surface phase and topographic phase. This paper proposed a new method for SAR interferometric baseline rectification specifically for SAR satellites those have no precise orbits. The method based on the imaging geometry of interferometric SAR, during the processing we setup a coordinate system called RXA, where R is a vector directing from the scene center to the corresponding position on the orbit, A is the vector of satellite velocity, X is normal to both R and A to construct a right hand coordinate system. There are two steps in our baseline rectification process, which are perpendicular baseline rectification and parallel baseline rectification, and the singular value of phase frequency was removed by the DIA method. In our study two InSAR pairs are processed, the results show the new proposed method could compensate not only the linear part of the orbit error but also nonlinear part of the orbit error.