Analysis of tropospheric effects on spaceborne single-pass SAR interferometry

Abstract

It is often considered that spaceborne single-pass interferometric synthetic aperture radar (InSAR) is not affected by tropospheric propagation effects, since the master and slave images are obtained almost simultaneously and needn't to resolve the problem of temporal decorrelation. However, due to the fact that slightly different incidence angles cause different propagation paths, the troposphere may result in a notable height error for single-pass InSAR systems. In this paper, the tropospheric propagation delay is divided into the common delay and the differential delay, and the corresponding height errors caused by the two delays are presented. Then, the absolute and relative height errors caused by troposphere for the flat and rough terrains are analysed using the proposed theoretical framework. Theoretical analysis shows that, when the swath width is 100km, the relative height and plane errors caused by the troposphere are 1.07m and 1.07m for the flat terrain, and 1.07m and 1.87m for the rough terrain. Moreover, comparisons between the results obtained under the two-dimensional baseline model and the three-dimensional one show that the two-dimensional baseline model is accurate enough for real data analysis with less complexity. This paper can provide some theoretical basis for the correction of the tropospheric effects in spaceborne single-pass SAR interferometry.