Development of a multi-frequency airborne radar instrumentation package for ice sheet mapping and imaging

We have developed improved versions of three different radar systems and integrated them as an airborne instrumentation suite for sounding and imaging Polar ice sheets. The first instrument consists of a multi-channel, coherent, pulsed radar operating at VHF with up to 20 MHz bandwidth. This instrument is capable of sounding a few-kilometer thick ice while flying at altitudes up to 10 km above mean sea level. The second instrument is designed to operate at UHF using a burst of narrow-bandwidth signals to digitally synthesize a bandwidth of in excess of 300 MHz. This apparatus is used to measure internal layers of the ice sheet to a depth close to 100 m. The third component to the instrumentation package is based on a frequency-modulated continuous wave (FMCW) radar, which operates at microwave (Ku band) frequencies with up to 1 GHz of instantaneous bandwidth. This radar set is used to measure the ice sheet surface elevation profile with centimeter accuracy. We are presenting a description of each system, with emphasis on the VHF depth sounder. We also present sample field test results obtained during the 2009 austral summer season in Antarctica, as a validation of the performance of the instrument package.