Beamwidth analysis for SAR processing of airborne depth-sounder data over ice sheets

Information on the bedrock topography below the Greenland and Antarctic ice sheets is vital to developing models of future sea-level rise. To measure the topography, advanced data acquisition and processing techniques, including Synthetic Aperture Radar (SAR), are required. This work investigates the optimal beamwidth that would enable SAR processing to maximize the signal to noise ratio of the target. Platform height above the ice surface and bedrock roughness determine the optimal beamwidth. We found that for data collected at a “typical” altitude of 867 m, the optimal beamwidth is about 8°. In the high-altitude case, we found that beamwidth did not have a significant effect on the signal-to-noise ratio. This is probably related to scattering from the ice surface.