ScienceDaily (Feb. 5, 2008) -- A space-based technology may provide an inexpensive and more reliable way to gauge the walking capacity in many patients with peripheral artery disease (PAD), whose clogged leg arteries cause them severe pain when they walk, according to a report in Circulation: Journal of the American Heart Association. A Global Positioning System (GPS) uses a constellation of at least 24 medium earth orbit satellites that transmit precise microwave signals. This enables a GPS receiver to determine its location, speed, direction and time.
