Research on Key Technologies of Precise In SAR Surveying and Mapping Applications Using Automatic SAR Imaging

Precise interferometric synthetic aperture radar( In SAR) is a new intelligent photogrammetric technology that uses automatic imaging and processing means. Precise In SAR has become the most efficient satellite surveying and mapping( SASM)method that uses the interferometric phase to create a global digital elevation model( DEM) with high precision. In this paper,we propose the application of systematic In SAR technologies to SASM. Three key technologies are proposed: calibration technology,data processing technology and post-processing technology. First, we need to calibrate the geometric and interferometric parameters including the azimuth time delay,range time delay,and atmospheric delay,as well as baseline errors. Second,we use the calibrated parameters to create a precise DEM. One of the important procedures in data processing is the determination of phase ambiguities. Finally,we improve the DEM quality through the joint use of the block adjustment method,long and short baseline combination method and descending and ascending data merge method. We use 6 sets of Tan DEM-X data covering Shanxi to conduct the experiment. The root mean square error of the final DEM is 5.07 m in the mountainous regions. In addition,the low coherence area is 0.8 km2. The result meets the China domestic SASM accuracy standard at both the 1 ∶ 50 000 and 1 ∶ 25 000 measurement scales.