Application of InSAR Monitoring Large Deformation of Landslides Using Lutan-1 Constellation
Objectives:Lutan-1(LT-1)satellites are the first scientific research satellite constellation with interferometric synthetic aperture radar(InSAR)measurement of surface deformation as its main features and focusing on long-term natural disaster monitoring and warning in complex areas.It consists of two L-band synthetic aperture radar(SAR)satellites with the same hardware parameters,and has high resolu-tion,high revisit,and full polarization imaging capabilities.The constellation uses the bi-satellites"sin-gle-pass in close formation"mode to map terrain,and the bi-satellites"repeat-track"mode to measure surface deformation.Taking the Xieliupo landslide in Zhouqu County,Gansu Province,China as a demonstra-tion example,the ability to monitor large deformation was tested using 4 d and 8 d high revisit observation data.Methods:The interferometric point target analysis(IPTA)method was used to perform InSAR defor-mation time-series analysis on the Xieliupo landslide.The artificial corner reflector(CR)and global naviga-tion satellite system(GNSS)were installed at the same location of the landslide,and the position of GNSS ground equipment was identified and confirmed by the CR on LT-1 data.The observation results of GNSS were used to verify the accuracy of InSAR results.Results:The annual cumulative maximum deformation of the landslide body exceeds 3.4 m.The accuracy of InSAR deformation time-series obtained from LT-1 satellites reaches 7.5 mm in line of sight.The maximum deformation rates of the tail,middle,and foreside of the landslide exceed 25 mm/d,11 mm/d,and 2 mm/d,respectively,which indicates the landslide is in the stage from slow sliding to very slow sliding.Conclusions:Through the comprehensive analysis of imaging mode,repeated observation interval,coherence change,baseline control range,and deformation detection ability,it can be found that the comprehensive efficiency of LT-1 satellite has reached the design indica-tors,and LT-1 satellite has good ability in regularized wide area surface deformation and monitoring.The high-frequency,strict regression,and consistent observation mode of LT-1 will play an important role in geological hazards identifying and monitoring on large-scale.
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