We're currently working on a project for an environment agency to determine viability / produce a proof of concept for monitoring methane levels over landfills using UAVs.
I can't really say much more than that its in the planning stages, and the software challenge I'm going to solve is principally dealing with fleet management .. 'drone is low power, return to base', 'replacement 2-of-3', &etc. The hardware guys have all the fun challenges: field-buildable/replaceable parts, autodocks for charging, etc. I'm just making a pizza app, basically. ;)