garymortimer writes "This technology, developed in the Autonomous Systems Laboratory at ETH Zurich, has two weighty advantages compared with GPS-based flying robots. First, it works both in the open air and in enclosed spaces. The second is that the flying robots can navigate where GPS fails; for example, due to the density of buildings. The camera-based technology allows for a more accurate positioning of the aircraft than is possible with GPS, explains the project coordinator, Davide Scaramuzza. Depending on the environment, GPS errors can be as great as 70 metres — much too imprecise when several flying robots are in close proximity to each other in the air." Link to Original Source
Economists state their GNP growth projections to the nearest tenth of a
percentage point to prove they have a sense of humor.
-- Edgar R. Fiedler