Global Positioning Systems

Part I of Essay
The new Avionics Modernization Program (AMP) systems installed in the F-111E and EF-111A have raised their share of questions, so I have decided to continue my series of "Everything You Always Wanted To Know" handouts to you pilots, navigators, and maintenance technicians o ....

Part II of Essay
.... whose lines intersected at two points. Even a vague guess of your whereabouts would be enough to discard the bogus point, and you'd be left with a pretty good idea of your position. Better yet, take a cut from a third DME transmitter and draw a third circle on your chart. Now you'd have three intersecting circles and your position would be inside the little triangle formed by the intersection of the three circles. Got the picture? This is basically how GPS triangulates, except that instead of circles, we're dealing with intersecting sphe ....