ther, competing satellite navigation efforts abroad are threatening to compromise the de facto monopoly GPS has afforded the US these past three decades.
Policy decisions past and present pertaining to GPS must be considered, criticized and amended. The decision process utilized by the Department of Defense on these matters must not hinder the trajectory of the GPS project. These issues, and others, will be considered in turn. First, however, it is prudent to explore the history of GPS and probe the some of the basic ideas that comprise this technology.
Looking back, it was the launch of Sputnik by the Soviets in 1957 that first shook the American defense agenda and forced a swift re-evaluation of the merits of space-based navigation; originally, this idea had been passed over by the US military.3 Years later, after developing many satellite navigation projects throughout the various military agencies, the Department of Defense consolidated what were believed to be the most promising elements in each of these extant projects and, over a holiday weekend in 1973, hatched the general concept for GPS.4 Today, 28 satellites comprise the basis of the GPS constellation. Orbiting nearly 11,000 nautical miles over the earth, these satellites communicate with a network of ground stations that in turn update and monitor the positions and time signals of their counterparts above.5
The basic theory behind GPS is, in essence, a geometric theory of triangulation. A basic idea, GPS is elegant in its simplicity: calculable distances between precise points will reveal exact locations, provided that the measurements taken reveal the distance between an object and three satellites (however actual GPS measurements incorporate readings from as many satellites as possible when determining global positions). Measurements taken between a man, X, on the ground and any three satellites A, B and C in orbit will allow X to triangulate ...