| Within a decade, synthetic aperture radar interferometry(InSAR) has matured to a widely used geodetic technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristics of the surface. The main objectives addressed in this article are to introduce the product of three years dedicated to the methods and applications of Differential SAR interferometry (D-InSAR) and Polarimetric SAR interferometry (POLinSAR). Key methodologies are listed.1. The article reviews the basic concepts of InSAR, the processing procedure for obtaining interferometric products such as a digital elevation model or a deformation map, and geodetic applications.2. A new three-step sub-pixel registration algorithm is introduced and implemented. The coregistration of SAR images is a strict requirement for interferometric processing. Based on the orbits of slave image and master image, the offset is first computed with an accuracy of about 30 pixels (precise orbits). Then, the offset between image pair is computed with an accuracy of about 1 pixel by maximum coherence estimation and "consistency test". At last, over the total image, for a large number of searching and matching windows, the offset between master and slave is estimated at a sub-pixel level.3. The surface seismic deformation of Zhangbei-Shangyi earthquake ( Ms 6.2) was measured using the three-pass ERS-1/2 SAR differential interferometric technology (D-InSAR). The focal mechanism of Zhangbei-Shangyi earthquake is estimated from the D-InSAR measurement of surface deformation based on a standard elastic dislocation model for seismic displacement. The inversion procedure is an iterative, linear least-squares algorithm. Through the relation between the focal parameters and displacement in the line of sight direction measured in the radar interferogram, the optimum focal parameter set is derived. The results show that the seismic fault of Zhangbei-Shangyi earthquake is a thrust fault dipping SW with a large right-lateral displacement component. The strike and dip are 95? and 30?respectively on a fault patch of 12 km long by 14 km wide. Its hypocenter is located at N40?8', E114?1', and 7.5km in depth. The estimated slip vector is 0.728m with a rake of 105.95? the trend of slip isNW13.26, and M0is 2.69N-m.4. Based on horizontal and vertical phase profiles, the atmospheric phase signal is analyzed between the high correlation region and low correlation region. Phase stacking method is applied to minimize atmospheric additional phase, and the results are validated by GCP.5. The potential of ERS-1/2 SAR interferometry for mapping subtle land subsidence has been investigated. A time series of ERS-1/2 SAR data from February 1993 to February 2000 is collected from measurements taken on Suzhou city, Jiangsu province, China; three differential interferograms were produced using three-pass method; which clearly show the spatial extent of land subsidence. The deformation maps are validated by leveling surveys, the correlation coefficient and standard deviation between them are 0.943 and 0.1706 respectively. Based on seven benchmarks, the subsidence rates are estimated, the overall trends are in close agreement with InSAR results. The results of study shows that for the mapping of land subsidence in urban environments InSAR has a strong potential with regard to cost effectiveness, resolution and accuracy.6. The basic concepts of POLinSAR are described. Combining optimum scattering mechanisms and Treuhaft's scattering model, the vegetation heights are retrieved. The performance of the inversion algorithm is demonstrated.7. A new classification scheme for single frequency polarimetric SAR data sets. A coherency matrix is constructed using single look complex data from single frequency images. Data sets are processed through a k-mean classifier after aninitialization step consisting of applying the Hlaly classification procedure.Compared with...
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