Research On Ionospheric Atmospheric Correction Method Of InSAR Time Series Based On TOPS

Interferometry synthetic aperture radar time series analysis is a further development of the traditional InSAR technology.It aims to analyze the temporal evolution of surface deformation.The Copernican Sentinel 1A/B satellites using the progressive scans(TOPS)mode for surface observations has brought unprecedented opportunities for measuring large-scale tectonic movements using InSAR technology.Although the Sentinel 1 satellite is equipped with a C-band sensor,its degree of impact on the ionospheric atmosphere is only one-sixteenth that of the L-band,but due to its special TOPS imaging mode,the measurement accuracy of short-wavelength signals will also be affected.With the increasing accuracy requirements of InSAR applications and the widespread use of Interferometric Wide Swath TOPS mode SAR data,the ionospheric atmospheric correction of TOPS mode interferograms has attracted more and more attention from experts and scholars.In China,the study of ionospheric atmospheric correction of InSAR of Sentinel-1 TOPS data is mainly for a interferogram,and the study of Ionospheric atmospheric correction of InSAR time series analysis is very little.This article will focus on this issue,the main research contents are as follows:1)Based on the basic properties of the ionosphere and the temporal and spatial distribution rules,this paper analyzes the effects of the ionosphere on SAR signal propagation and the impact of TOPS mode SAR image acquisition.The two effects of TOPS imaging under the background of single-layer ionosphere and the final manifestation on the interferogram are elaborated in detail.The TOPS interferogram covering the range of 250km×520km in northern Chile was used to demonstrate the influence of the ionospheric atmosphere on the TOPS interferogram.2)In this paper,the Split-spectrum method suitable for TOPS interferogram ionospheric atmospheric correction is elaborated,and the method is used to perform ionospheric atmospheric correction on the more serious interferogram of the ionospheric atmosphere,and the effect of TOPS mode interferogram ionospheric atmospheric correction is demonstrated.3)A selective ionospheric atmospheric correction method is proposed for interferograms involved in time-series InSAR inversion is proposed.the Northern Chile are used as research areas,90 scences of Sentinel-1A IW TOPS data and 52 scences of Sentinel-1B IW TOPS data were used for NSBAS-InSAR ionospheric atmospheric correction experiment respectively.Experiments show that after the ionospheric atmospheric correction,the time series analysis results have been significantly improved.The comparison of the results of the two track time series analysis results proves that the method is effective.