Some Key Technology About Extraction Digital Elevation Model From SpaceBorne Interferometric Synthetic Aperture Radar Image

InSAR (Interferometric Synthetic Aperture radar) is currently a hot topic by the phase information from SLC data of Radar, which has achieved in various fields such as the generation of digital elevation models(DEM), the detection of small surface deformations, land subsidence. This paper goes deep into the interference imagery mechanism, from the application requirement of surveying and mapping, stresses solving InSAR Key technology on automatic generation quickly interferogram and convert of phase to height。Firstly, this paper investigates basic principle, mathematical model, data processing flows and key technology of INSAR in detail. Then goes deep into the co-registration of SLC. Based on analysis the present algorithms and the contrast between the method based on correlation coefficient and the method based on max-spectrum, an automatic approach with multi-step co-registration algorithm is present. Results indicate that algorithm and model is reasonable and it adapts to space-borne INSAR data。 The phase filtering of interferogram is also an important aspect in INSAR data processing. A gradient weighted periodic median algorithm is presented for removing the noising in the interferogram.In this paper, primary algorithms of convert of phase to height are introduce, and they are divide into three kinds. A algorithm based on the difference phase of neighbor is present. Sample experimental results indicate the algorithm based on single point INSAR model is efficient。General speaking, this paper includes the following aspects: First, introduction of InSAR. Second, the principle of InSAR. Third, an automatic algorithm for precision co-registration and enhancing the interferogram. Fourth, ,the convert of phase to height, and giving their experiment results. Finally, summarizing this paper about InSAR.