| According to the latest 2013 China Land Resources Communique:a total of 15403 geological disasters occurred in China, in which there are 9849 from landslides, accounting for 64% of all types of geological disasters, landslides seems to have become the most serious natural disasters in China. Now days, how to implement an effective monitoring and early warning become particularly important for protecting people’s livelihood. Traditional landslide monitoring, which can’t response the overall landslide deformation trend very well because of the sparse monitoring point. Thanks to the development of Synthetic aperture radar (SAR) technology recently years, which can make up for the deficiency of the traditional monitoring methods and have the advantage of monitoring the ground surface with all weather and high precision.This study is focused on the approach of Shuping landslide in Three Gorges Reservoir Area using D-InSAR and Offset tracking methods and extracted the landslide deformation field throughout the year. Then an algorithm is proposed based on least square for Atmospheric phase removal problems in D-InSAR technology. Finally, using the GPS measurements result to verify the accuracy of the two methods.In this paper, results and conclusions are as follows:(1) Using 10 views TerraSAR-X 3m resolution strip mode datas and D-InSAR method acquired a total of eight images of shuping landslide deformation field in 2012 from January to March and December. Analysis showed that. D-InSAR can accurately extract the landslide field in a slow deformation, the maximum deformation rate of Shuping landslide in this time was about 1cm/month.(2) Using 3 views TerraSAR-X 1m resolution fine mode datas and using Offset tracking method acquired two pair of shuping landslide deformation field in 2012 from April to November. The results showed that, the maximum deformation rate of shuping landslide in the mutant phase reached 15cm/months.(3) Improved the algorithm of atmospheric phase removal in D-InSAR. Based on the least square method, this paper extracted the stable regional atmospheric delay phase and the corresponding elevation values to fitting the quadratic polynomial curve, then, simulation the atmospheric of delays deformation area with fitting polynomial, finally remove the atmospheric phase form the interferometer phase.(4) Using the measured data and the existed data, qualitative and quantitative analysis the accuracy of the D-InSAR and Offset tracking methods. The results is showed that the overall Shuping landslide moving northward, at the same time, two small local landslide with larger deformation development on it. In comparison with the ground measured truth data is showed that:D-InSAR technical monitoring accuracy within the lcm, Offset tracking accuracy is about5-10cm.(5) Analysis the applicability and advantages of the two extraction methods. D-InSAR technique have the accuracy with sub-cm, and it’s very sensitive to the change of terrain, it’s easily to extract a landslide deformation field with slow deformation, but it requires two images with a good coherence, so for, it’s useless in the areas with serious loss of coherence. Offset tracking technology has a low requirement of coherence because of it’s rely on the strength information of image. So, it can be a good complement with D-InSAR technology. However, the accuracy of extracted results by Offset tracking method is limited by the serious noise interference and its theory. |
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