Monitoring The Active Fissure Based On CRInSAR

InSAR(Synthetic Aperture Radar Interferometry),as a new technology to monitor the large scope surface deformation,has been developed rapidly in recent twenty years.It has the advantage of all-weather, large-scale, high accuracy and has become a very promising technology in the field of monitoring geological disaster. However, due to the temporal and spatial decorrelation and the delay of atmosphere, especially the resolution limit, InSAR is limited to monitor these small-scale area deformation or large magnitude deformation such as ground fissure, structural fracture and mine collapsed areas. Inversely, CRInSAR can overcome the traditional decorrelation and atmosphere delay and can solve the problems of small-scale area deformation or large magnitude deformation when uses the full-resolution, so it has a bright future and becomes a hot topic. Therefore, it has strong realistic meaning and research value to monitor the ground fissure activities based on CRInSAR.In this paper, the two fissures of Xi'an are the research objects. Based on the principle of InSAR, the mathematical model and data processing cycle of CRInSAR are deduced. Trihedral angle corner reflector is designed by the reflection characteristic and the paper presents a new CR identifying idea-intensity deviation method. About the unwrapped methods which are the key problem for CRInSAR, the LAMBDA method (one of the method of the GPS integer ambiguity search) is introduced to solve the phase wrapped problem. As to the error control, the theory of integration GPS and CRInSAR to correct the DInSAR is studied. On the whole, the main works and contributions are summarized as follows:1:The research of CRInSAR's phase observation model and stochastic model.The paper analyses the component of InSAR and the error source, then proposes the idea of CRInSAR and presents the functional model and stochastic model.2:A new CR identifying method based on intensity deviation. Pitch angel must been designed to obtain the maximum Radar Cross Section (RSC). It is difficult to identify real CR point in the city because of much scatterer around. However, it is convenient to detect the CR by comparing with the intensity information before and after the CR installations.3:CRInSAR phase unwrapped based on LAMBDA. It is feasible to unwrap the CRInSAR by analyzing the principle of LAMBDA. Using the LAMBDA method, CRInSAR phase unwrapped formula is deduced. At the same time, virtual observation values are adopted to solve the rank defect of model.4:DInSAR error analysis based on integration the GPS and CRInSAR. About the atmosphere delay, CR/MODIS methods are discussed. Geocoded error is very common and affine transformation model is presented to correct it. In the end, fissure surface profile is explored by correcting the DInSAR's topographical phase, filtering phase and unwrapped phase.5:Monitoring the fissure of Xi'an based on CRInSAR. Taking the f3 and f11 ground fissure as the example, the relative deformation beside the fissure is calculated by CRInSAR. Comparing with the leveling result, the difference is 1.6mm which proves the reliability of monitoring the fissure using CRInSAR. The back calculation results of atmosphere delays of eight interference pairs demonstrate that the influence of atmosphere delay can reach centimeters and is related to the range of reference point. The surface profile of f3 and f11 explored by corrected DInSAR is coincident with the geological information.