from the because-life-just-isn't-worth-living-otherwise dept.
Zothecula writes "The Global Positioning System (GPS) has proved a boon for those with a bad sense of direction, but the satellite-based system isn't without its shortcomings. Something as simple as going indoors or entering a tunnel can render the system useless. That might be inconvenient for civilians, but it's potentially disastrous to military users, for whom the system was originally built. DARPA is addressing such concerns with the development of a self-sufficient navigation system that can aid navigation when GPS is temporarily unavailable."
"Don't worry about people stealing your ideas. If your ideas are any good,
you'll have to ram them down people's throats."
-- Howard Aiken