1994

Global Positioning System (GPS)

Ivan A. Getting (1912–2003), Roger L. Easton (1912–2014), Bradford Parkinson (b. 1935)

If you were an engineer working on the Global Positioning System (GPS), you were doing something incredible. You were proposing the creation of a new sense that could become available to every human being on the planet. Humans come equipped with the normal senses: vision, hearing, smell, taste, and touch. But humans definitely do not come equipped with a sense of direction, especially at night, especially on the open oceans, especially in bad weather where clouds, fog, and rain obscure every landmark.

The GPS engineers, a team including Ivan Getting, Roger Easton, and Bradford Parkinson, who were working for the United States Department of Defense, proposed to change all of that. By 1994, they had created a ubiquitous, instantaneous, and precise system by which any human could locate his or her exact position on the planet with roughly 30-foot (10 meter) accuracy, anytime, anywhere.

One of the most audacious parts of the proposed system would be the cost—approximately $12 billion for a constellation of 24 satellites funded by the US military that went into orbit between 1989 and 1994. Another audacious part was the technology. This new GPS system demanded small, accurate atomic clocks that could operate unattended for years in orbit—two of them per satellite. These clocks are not simple devices. And then there was the technique the engineers devised to determine location. A GPS receiver would need to be able to see at least four satellites overhead, know exactly where each is in orbit, and then determine exactly how far away each one is. Using the distance and location of the four satellites, the receiver could triangulate its exact position and altitude on earth. It could also derive the exact time with atomic clock accuracy without needing to have its own atomic clock.

Here on Earth, the arrival of the cheap consumer GPS receiver combined with the arrival of the cheap, pocket cell phone to make it seem like we were living in the future. It is an amazing pair of capabilities for any human to have.

SEE ALSO Atomic Clock (1949), Space Satellite (1957), Mobile Phone (1983), Self-Driving Car (2011).

White iPhone 5 with Google Maps app on the screen.