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Synthetic Aperture Radar (SAR) Interferometry, usually referred to as InSAR or IFSAR, is the synthesis of conventional SAR.techniques and interferometry techniques in radio astronomy.It has enabled fine spatial resolution, wide coverage, and competitive accuracy measurements of ground deformations related to, e.g.,earthquake, volcano, and underground work.Such measurements are however affected by the atmosphere and the decorrelation noise.With an aim to improve the accuracy of InSAR measurements, this report investigates the ways to mitigate the effects from the atmosphere and the de correlation noise. Firstly, using Shanghai as an example, this report analyze the characteristics of atmospheric effects in SAR interferogram.The results show that atmospheric effects in SAR interferograms are anisotropic, non-Gaussian and following approximately a power law distribution.The scaling exponents estimated show that the atmospheric signatures in all the interferograms are non-stationary but with stationary increments.It is estimated based on the estimated scaling exponents that external data with spatial resolutions as high as about 0.3 km, are required to determine and correct for over 90％ of the atmospheric effects in the SAR interferograms.Based on the results, an elevation-dependent InSAR atmospheric correction model is developed.Test results over Mount Etna with data from 16 continuous GPS stations show that an improvement of about 27％ can be achieved when applying the model. Secondly, this report investigate the ways to mitigate the decorrelation noise with post-filtering.Two filters have been developed in this part.The first one is an improved version of the commonly used Goldstein filter, where a new noise-dependent filtering parameter is defined to replace the original constant filtering parameters.Very consistent results can be achieved when the improved Goldstein filter is applied to interferograms with different noise level.The second one is an extension of the one dimensional Vondrak filter, i.e., a two dimensional (2D) Vondrak filter.Test results show that the 2D Vondrak filter outperform some existing filters.