SAR Interferometry for Improved Terrain Corrections in Surface and Airborne Gravimetry

Abstract

Derivation of Digital Elevation Models (DEM’s) by ERS SAR interferometry is a promising method for obtaining the necessary elevations for computing accurate terrain corrections in remote, poorly surveyed areas. InSAR DEM’s are especially useful due to the inherent high spatial resolution. In the poster the quality of a SAR derived DEM of an East Greenland area is evaluated based on comparisons to geodetic control points and airborne laser altimetry.

The impact on terrain corrections for both surface and airborne gravity surveys is evaluated by comparison to computations based on previous DEM’s. Results show that effects can often be 10 mGal (1∙0^–4 ms^-2) or more and especially affecting airborne gravimetry. Derivation of SAR DEM’s are, however, not without problems since atmospheric effects, phase unwrapping errors, shadowing and foreshortening/lay-over may produce systematic errors and data voids especially in areas with very steep slopes.