Yong Fang 
  
DEM GENERATION FROM MULTI_SENSOR SAR IMAGES 
Fang Yong, Chang Benyi, Hu Wensong, Chen Hong 
Xi'an Institute of Surveying and Mapping, China 
heyfgl6@public.xa.sn.cn 
KEY WORDS: Multi Sensor Images, Radargrammetry, Radarclinometry. 
ABSTRACT 
In order to realize mapping the areas that are covered by clouds all the year round, it is an efficient way 
to combine multi sensor images to do stereocopy. The paper discusses the theoretical basis of using 
different sensor SAR images to extract DEM, which key point lies in space intersection and image 
match. For the sake of improving the quality of DEM acquired by using radar stereo 
photogrammetrical method, radarclinometry is adopted to do further refinement. The experiment 
results show that using same side ERS-1 and RADARSAT-1 data with 20^ intersection angle: to 
acquire DEM, the accuracy of plane is 70m and that of height is 28m. 
1 INTRODUCTION 
Synthetic Aperture Radar (SAR) is a kind of microwave sensor developed in the later 1950s, and is one 
of most effective and fastest developed earth-observation system in the field of microwave sensor. It 
has such features: 
(1)all-weather and all-day work ability, which can remedy the imaging blind areas caused by the 
restriction of optical sensors in work time and weather; 
(2) having a certain ability of penetration, which can penetrate the earth surface cover and gain 
the underground information; 
(3) providing more abundant earth surface information, which can remedy the defect of other 
sensors’ not getting enough information. 
For these outstanding advantages, SAR is applied widely. It has more superiority especially in the field 
of mapping the areas covered by clouds all year round. In the respect of extracting DEM from SAR, 
current main technique ways include radargrammetry, InSAR and radarclinometry. Comparatively 
speaking, InSAR sets strict demands on initial data, and it suffers much limitation and always cause the 
coherent results can't meet the needs of practical requirement for data difficult to meet the interference 
conditions. Similarly, applying stereo photogrammetry theory to extract DEM from SAR images will 
  
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B1. Amsterdam 2000.