Students at MIT in the States have developed a very sophisticated piece of kit with huge survey potential especially underground where GPS signals are unable to be monitored.
The micro aerial vehicle maps its surround on the fly using a laser. It then uses the information to navigate itself around its environment, continually re-mapping as it goes.
Most definitely a must have for the mine/cave surveyor I would have thought.
See the video here:
http://blog.makezine.com/archive/2009/10/mit_uav_uses_lasers.html The base vehicle is an electrically powered microcopter so from an emissions point of view in a confined space it is friendly. Quite sure there'll be a packaged version complete with software in the future.