Unmanned Aircraft System for Radar Sounding and Imaging of Ice Sheets

News

By Tyler Wieland
Winter 2014

A team of researchers from the National Science Foundation (NSF) funded Center for Remote Sensing of Ice Sheets (CReSIS) at the University of Kansas has developed an Unmanned Aircraft System (UAS) integrated with a compact radar depth sounder that operates in both the HF and lower VHF ranges for sounding ice and imaging the ice-bed interface in Antarctica and Greenland.

UAV

CReSIS UAS on approach to land at the SLW field camp, Antarctica. (Courtesy of Shawn Keshmiri)

The UAS is designed to perform surveys over a two-dimensional grid, synthesizing a large 2-D aperture and generating fine resolution both in the along and cross-track directions. Low-frequency high-sensitivity radars with 2-D aperture synthesis capability are needed to overcome the surface and volume scattering that masks weak echoes from the ice-bed interface of fast-flowing glaciers. The complete system weighs about 37 kg when fully instrumented and has a range of 225 km on slightly less than one gallon of fuel.

The radar system on the UAS weighs about 2 kg and operates at 14 and 35 MHz with 1 and 5 MHz of bandwidth, respectively. The radar system transmits up to 100 W of peak power at a pulse repetition frequency of 10 kHz and consumes about 20 W of DC power. Command and status are accomplished through a serial connection to the on-board autopilot for wireless communication with the ground station, while science data are streamed to an on-board high-capacity SD card.

Radar

A photograph of the radar electronics (left) and two radar echograms generated from 35 MHz (middle) and 14 MHz (right) data collected over the 800 m-thick ice during approximately 15 repeat passes over the ice. (Courtesy of Carl Leuschen)

This radar-equipped UAS is being flight tested at the Sub-glacial Lake Whillans (SLW) field camp on the Whillans Ice Stream in Antarctica, and the first successful demonstration of sounding ice with a radar on a UAS has been achieved. The flight test data and radar data will be processed and analyzed after the team returns to Kansas. CReSIS is planning to build multiple radar-equipped UASs for collecting fine-resolution data near the grounding lines of fast-flowing glaciers and will be also be reducing the weight of the radar to approximately 1 kg.