GPS - How it Came to Be

GPS. Something the US military created. And something that makes navigation via Google Maps possible. That’s how I thought of it. That’s so much the norm that Greg Milner writes in his book, Pinpoint:

“In the age of GPS, we don’t require the environment to locate ourselves.”

Who needs landmarks when you have GPS to tell you where you are?!

 

The idea of GPS was conceptualized when the Soviets launched the first satellite, Sputnik, in 1957. To prove they had really done it, the Russians put an on-board transmitter. Check the strength, movement and pattern of the signal, they said. It could only come from something in orbit. Two American scientists, William Guier and George Weiffenbach, flipped that point around and realized that the satellite could detect the position on land by the same principle. In theory.

 

To achieve it in practice, GPS needed multiple satellites. And to make GPS accurate at the level we take for granted, “the clocks cannot falter”:

“A timing error of just one-millionth of a second will translate into a distance error of 200 miles.”

The satellites have to adjust for Einstein’s laws of relativity: time flows at the different rates on the surface of the earth and in space. But that’s easy: just do the maths. But how to keep time with such accuracy? This was the problem that led the world to switch from its conventional sources (movement of the earth around the sun, perceived movement of the stars wrt the earth) to the clock built in nature itself: atomic clocks.

 

Now comes the inevitable politics and luck involved in any such tale. If it could be built, who would be its biggest users? The submarines and ships of the navy, out there at sea, obviously. But satellites for GPS fell under the Air Force. Why would the Air Force want to spend its budget on something that didn’t help the Air Force? Benefits like precision bombing and obviating cloud cover problems weren’t very appealing to an Air Force that, since World War II and Vietnam, used to indiscriminately and repeatedly bomb. Who needed precision bombing?

 

And so the idea never really picked up. While it moved slowly, it was always under danger of being stopped. Until the stroke of luck arrived: the first Gulf War in 1991. To push Saddam out of Kuwait, the Allied armies needed to march through desert. And a desert is featureless, with no landmarks. Suddenly, it was the Army that saw the greatest use for GPS!

 

There were major hurdles: the satellite signals had been encrypted since the US didn’t want their enemies to use the signal. Military grade GPS receivers were few and expensive since nobody really wanted them. Until now. But production could not be turned up in time for the Gulf War.

 

Some private sector players had been manufacturing cheaper GPS receivers in the US for marine navigation by civilians. Even without access to the encrypted signals, the signals still gave better positioning info than existing civilian navigation systems. If the US military wanted to use those receivers, they had to turn off the encryption so that the existing, often cheaper, civilian grade receivers would become good enough for the Army! So they turned off the encryption.

 

The Gulf War thus became a very public demonstration of the power and accuracy of GPS. The genie was out of the bottle, and while the military repeatedly turn off the (un-encryption) tap after the Gulf War, the commercial possibilities of GPS were now all too evident. And in America, the market and business prospects trump everything else…