The work of a computer scientist at Aberystwyth University has helped capture images of Greenland glaciers for the purpose of building digital elevation maps and gathering glaciology data for research.
Dr Neal Snooke, a lecturer at the Department of Computer Science, has been working on unmanned aerial vehicle (UAV) technology, commonly known as drones, for the past three years.
In June, six new UAVs were sent to Greenland fully equipped with Sony Alpha 14 megapixel cameras to capture high quality photographic data of Store and Lille glacier, which flows into the sea off Greenland.
Dr Snooke explains, “The mission was a great success. We were able to capture thousands of high quality digital images that can be processed to produce high resolution 3D models of the glacier. The images showed and monitored the movement and calving of the glacier on a frequent basis.
“The idea came in the spring of 2013 when talking to Professor Alun Hubbard from the Department of Geography and Earth Sciences to use inexpensive UAV technology hardware to capture high quality digital images for research purposes.”
“In the future, the UAV technology should allow investigation of the effects of large calving events, sub-glacial lake drainage or ice mélange breakup on the Store and Lille glacier.”
The aim was to create an autonomous UAV that could fly 7 kilometres along a glacier front and a couple of kilometres from the launch site. Typical missions cover a distance of around 60km at 55kph carrying 700g worth of camera equipment, and are in the air for about an hour.
Two prototype UAVs were built and taken to Greenland in 2013 to assess their potential and around 20 missions were completed. This year, the team set out to create a small fleet of UAVs to undertake a variety of missions.
Called the Skywalker X8, the airframe is a flying wing design, large enough to allow a high quality camera to be fitted inside and to accommodate the electronics and batteries. It has a 2 meter wingspan, weighs around than 2.5Kg, and is constructed from expanded polypropylene foam, making the frame quite robust and easy to repair.
Improvements were made to the new UAVs which went to Greenland. These included electric brushless motors and modifications to the airframes to reduce the potential for damage caused by the need to land on rough terrain or ice.
Software improvements allow the camera to be triggered directly from the autopilot allowing capture of the GPS position and flight attitude data associated with every photograph.
Dr Snooke and his team are currently integrating additional sensors such as a pyranometer to enhance the scientific value of the data captured. In the future, they would like to increase mission endurance as this will provide a number of opportunities to routinely collect data from more inaccessible areas.
The team is also working to make the system more adaptable, for example by allowing the UAV to automatically shorten its pre-programmed mission if strong crosswinds are encountered to avoid any danger of running out of power.
He adds, “Johnny Ryan, a PhD student at the Department is currently undertaking the day-to-day flying and research work in Greenland.
“This work is another excellent example of good collaboration work between the Department of Computer Science and other departments and disciplines. The glaciologists have the science application and the computer scientists have the expertise in robotics and software needed to build the systems to make it happen.”
Repeat UAV photogrammetry to assess calving front dynamics at a large outlet glacier draining the Greenland Ice Sheet, a paper published on the research by Professor Alun Hubbard and Johnny Ryan’s in the journal of the European Geosciences Union, The Cryosphere, can be viewed online at http://www.the-cryosphere-discuss.net/8/2243/2014/tcd-8-2243-2014.html.
