Study On Removal Of Insar The Ground Effect And Phase Noise Suppression Method

Interferometric synthetic aperture radar (InSAR) imaging technique is one of the main content of the microwave remote sensing, this is due to the fact that it has many advantages over other imaging methods, such as large coverage, high spatial resolution, high elevation accuracy, and the capability of working at all time and under all-weather conditions. It is the most effective method to acquire the three-dimensional Digital Elevation Model (DEM).This paper discusses the basic principles using InSAR technique to acquire DEM and the main steps of the InSAR data processing, analyzes the factors leading the data decorrelation and presents a more detailed discussion on the key techniques of the InSAR data processing, such as the single look complex (SLC) image registration, flat-earth effect removing and interferogram noise filtering.The paper studies the method of InSAR complex image registration. The precise registration increases the coherence of the interferogram, considerably reduces the phase noise, improves the quality of the phase unwrapping procedure and leads to a more accurate phase in the final interferogram. After the coarse registration by using Conventional techniques of cross correlation, interpolates one of the two amplitude images according to the offset of the matching position between two images and then resamples the image to accomplish the subtle registration. The emulation result validates the arithmetic of based on cross correlation of the detected amplitude images is satisfied.The effect of flat-earth remove is an important step in InSAR data processing . The flat-earth makes the main frequency of the interferogram not at the zero frequency, and can't reflect the change of the topographic altitude. The paper proposes a method of removing flat-earth effect by moving frequency to zero to remove the flat-earth effect.The interferogram without flat-earth is severely contaminated by noises and can't be directly used in phase unwrapping. The paper presents a thorough study on denoising of the interferogram. On the basis of the traditional arithmetic of noise filtering research, this paper presents a filter arithmetic based on frequency weighted. The emulation results show that the number of residues decreases, the stripes of the interferogram are more clarity and validates the denoise method is feasible and effective.