A comparison of atmospheric disturbance correction techniques in GBInSAR

Abstract

Ground-Based Synthetic Aperture Radar interferometry (GBInSAR) has generated movement with sub-millimeter accuracy in line-of-sight(LOS) direction, and it can provide movement images with high spatial and temporal resolution. Though the fluctuation of atmospheric environment affects interferometric phases strongly, GBInSAR can be used for deformation measurement after removing the interference phase and transforming the displacement from LOS direction to radial and tangential. This paper provides a comparison of different atmospheric disturbance correction techniques. We made an experiment of deformation measurement about Geheyan Dam on Qingjiang to estimate the movement caused by atmosphere. In the experiment, displacement information of the dam was obtained by IBIS-L system and atmospheric parameters (humidity, temperature and barometric pressure) were collected from the weather station located on the dam. The collection process lasted for several days. By processing and analysis the data of a whole day without equipment malfunction, the results show an atmospheric delay of 15mm when the system located 1000m away from the target dam and atmospheric correction should be reinforced somehow for most Ground-Based InSAR applications. Then three correction algorithms are presented in order to weaken the influence from atmospheric disturbance. The techniques respectively based on the atmospheric parameters, Ground Control Points(GCP) and distribution model are quantitively compared using a reference dataset gotten by inverted perpendicular lines. And the accuracy of each method are finally drawn. It could be seen that the atmospheric disturbance be weaken by the three methods with reliable results and error of the technique based on distribution model was less than 2mm with the highest reliability. This analysis is followed by a discussion of the advantages and the limitations of each technique.