Research On Extraction Of High-Precision DEM Based On InSAR Baseline Correction

Synthetic Aperture Radar Interferometry (InSAR) is a high precision earth observation technology developed since 1960's. InSAR was widely noted by International Mapping Community for its advantages such as high-speed, high accuracy, full time, full weather and large area observations, etc. Currently, the use of InSAR to extract digital elevation model (DEM) has become one important direction of national remote sensing research field. This article aims to explore a method of using external ground control points to accurately correct baseline, thus to improve the accuracy of DEM.Baseline is key parameters in InSAR. It determines whether the interference measurement is able to carry out, and it also determines the accuracy of final results. The accuracy of baseline has a great impact on DEM. As baseline is the leading cause of coherence loss, we need to accurately estimate baseline.This article systematically illustrated the basic theory of InSAR/D-InSAR and the concept of baseline, analyzed the impact of baseline on the accuracy of measuring heights, summarized several baseline estimation methods that currently common used, and compared the advantages and disadvantages of these methods and their application conditions.In this article, I commenced my study combined with the research project of country 863 project "Application Research on Earthquake Monitoring and Disaster Assessment Using Multi-Source Space-time Remote Sensing Combined with Surface Seismic Observation Data". For the direction of microwave remote sensing, according to the basic principle of Repeat-track Interferometry, taking the spatial geometric relationship into account, systematically studied the accuracy of measuring heights caused by baseline, and analyzed the theory models of different baseline estimation algorithms and their advantages and disadvantages. Emphasis has been placed on researching the InSAR baseline estimation algorithms using additional ground control points, and writing a program of "InSAR Baseline Fine Correction Algorithm using Ground Control Points (InSAR-BLFCA)". In this study, take the ENVISAT ASAR data of Dujiangyan region that was serious damaged in Wenchuan Earthquake as research area, using the program to calculate baseline. The results show that, in the condition of enough ground control points, DEM generated after baseline correction can basically meet the accuracy index requirements of national 1:50 000 DEM level three products.