Interferometric Phase Error Analysis and Compensation in GNSS-InSAR: A Case Study of Structural Monitoring

Abstract

Global navigation satellite system (GNSS)-based synthetic aperture radar interferometry (InSAR) employs GNSS satellites as transmitters of opportunity and a fixed receiver with two channels, i.e., direct wave and echo, on the ground. The repeat-pass concept is adopted in GNSS-based InSAR to retrieve the deformation of the target area, and it has inherited advantages from the GNSS system, such as a short repeat-pass period and multi-angle retrieval. However, several interferometric phase errors, such as inter-channel and atmospheric errors, are introduced into GNSS-based InSAR, which seriously decreases the accuracy of the retrieved deformation. In this paper, a deformation retrieval algorithm is presented to assess the compensation of the interferometric phase errors in GNSS-based InSAR. Firstly, the topological phase error was eliminated based on accurate digital elevation model (DEM) information from a light detection and ranging (lidar) system. Secondly, the inter-channel phase error was compensated, using direct wave in the echo channel, i.e., a back lobe signal. Finally, by modeling the atmospheric phase, the residual atmospheric phase error was compensated for. This is the first realization of the deformation detection of urban scenes using a GNSS-based system, and the results suggest the effectiveness of the phase error compensation algorithm.

Data Acquisition of GNSS-Based InSAR: Joint Accuracy-Efficiency Optimization of 3-D Deformation Retrieval

“…Based on the algorithm proposed in [53], the PS points can be selected. The algorithm proposed in [15] is selected to obtain the deformation retrieval results. The number of PS points and 3D deformation retrieval accuracy are shown in Table VI.…”

“…The phase of the resolution cell is contributed by the PS point and other weak targets in the resolution cell around the PS point. The spatial coherence of the PS point can be disregarded, but the spatial coherence of other targets must be considered [15]. The lower the spatial coherence coefficient is, the greater the influence of the weak targets on the interferometric phase of the PS point.…”

“…Based on GNSS-based SAR, GNSS-based SAR Interferometry (InSAR) was introduced [12], [13]. The greatest potential application of such a system is surface deformation monitoring by using repeat-pass interferometry [14], [15].…”