Effect of Reference Height Points, their Number and the Source on InSAR DEMs

  • Kesavarao P


Reference height points play important role in the process of InSAR DEM generation from two aspects; for conversion of relative to absolute heights and for DEM error estimation. Usually, the input reference point heights are fed by visual common feature tie up method which is time consuming especially in SAR single look large images. This tedious feature identification process is overcome by inputting an external open source DEM during intermediate stages of InSAR DEM generation. Ten InSAR DEMs are generated by each of these methods and compared. Besides, DEM error estimation is done by pixel height matching technique using accurate Carto DEMs and also by limited GPS control points. Statistical error estimates are studied by varying the number of check point height. The estimated error dependence on the number, type and accuracy of check points is reported.