Studying Methods Of INSAR-DEM Geocoding

INSAR technology has great advantages: without limited to weather, high resolution and high precision. Because of it's wide application, INSAR has became a popular topic today. It obtains images of the same area at least two times from different satellite position and calculates the relative height from the phase difference. By reason of geometric distortion, the INSAR data has distortion. In the process of generating the DEMs which accord with the relief map, the effect of distortion must be removed. This is the geocoding process, which is discussed in this paper.In this paper, the author introduces the development of INSAR technology , analyzes the principle of INSAR technology and discusses the theory of geocoding, the Significance , the common flow and some models and methods used often.. Range-Doppler model not only makes full use of satellite ephemeris data, but also considers that the reflected wave is not perpendicular to the aspect of the satellite track. This model can avoid errors brought in the process of slant to ground range transform, so the author focuses on the Range-Doppler model, works out the iteration formulas for SAR allocation and SAR geocoding. What is more, the detailed process of SAR allocation and SAR geocoding is interpreted, as same as the principle DEM generation and orthoimage generation.The calculation of satellite orbit is the precondition of Range-Doppler model, so two methods of orbit calculation are explicated . They are Doppler parameters method and polynomial-fitting method , further more, the validity and precision is tested by experiment.Finally, some experiments on Range-Doppler model are carried out. DEMs and orthoimages are obtained from raw image and raw DEM data.