Where on Earth?

Abstract

This article discusses how global positioning system (GPS) provides guidance for a new generation of unmanned surveillance aircraft. Traditional methods of surveying, for example, require benchmarks of known coordinates, followed by a sequential process of measuring angles and distances to calculate the coordinates of any other point. A GPS receiver uses satellites for benchmarks and rapidly processes timed signals into precise values of longitude, latitude, and elevation. GPS-based air traffic control is just beginning to be realized. GPS may also have profound consequences beyond those that can now be identified. Humans have only recently had access to portable and affordable clocks to measure time. Originally a tool for the military, the GPS now provides us with a device to extend the measurements into the three dimensions of space. More unintended consequences for the human condition are quite possible in the future.