A Study Of The CRInSAR Atmospheric Correction Model And Its Preliminary Application

Our country have a vast territory and complicated natural conditions. The observationsal stations for crustal deformation are very sparse, hence acquiring the auspice of seismic deformation field and fault activity information is severely limited. The Spaceborne InSAR(Synthetic Aaperture Radar Interferometry) technology developed in recent ten years is not limited by regional factors, which can work under all weather during day and night. So it possesses irreplaceable advantage to obtain continuous surface deformation field of areas with complex natural conditions. Although InSAR make up for the lack of many former measuring methods(such as leveling, GPS etc), and can monitor large-scale surface deformation, possessing immense mercantile, its limition of application can not be neglected. At present, the orbit model of InSAR usually adopts the repeat-pass model. Its imaging mechanism brings about some uncertainties of results, such as temporal unrelated, spatial unrelated and delay caused by atmospheric effect. All these influential factors can affect deformation interferometry. Especially in vegetative cover areas, temporal uncorrelated is very serious. For the temporal change in the complex reflectivity of the ground surface during the period between radar acquisitions, the coherence of SAR images become very bad, even unrelated, make phase unwrapping be very difficult, affecting accuracy of interferometry directly. Moreover, atmospheric effect on InSAR is very great. For C band interferometric images, relative atmospheric change 20% will result in errors of two or three fringes (per fringe means 2.8cm deformation in slant direction), and the total error reaches 6~9cm.From the mid 1990s, some foreign scholars began to apply some new technology to solve limitations of conventional InSAR. In these technology, the appearance of CRInSAR(Corner Reflector InSAR)and PSInSAR(Permanent Scatteres, InSAR) enhances effectively temporal coherence and spatial coherence of these repeat-pass image series, making those interferometric image pairs covering the same area near critical baseline or at intervals of 5~6 years be applied , realizing observations of small deformation of vegetative cover areas. Moreover, accuracy of CRInSAR monitoring is better than accuracy of conventional InSAR, which attracts much attention of scholars at home and abroad. They have studied these new technologies deeply and achieved some results.Because CR reflects radar waves very strongly with uniform size and specification, obvious star-like bright spots appear on SAR images and are esay to be recognized. So CRInSAR gets more concerns. Though repeat-pass CRInSAR makes up for some limitations of conventional InSAR and enhances accuracy of monitoring,...