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Nashua;82.0;;2014-07-28 14:25:36
Wednesday, April 7, 2010

N.H. brain behind GPS in hall of fame

David Brooks

If you think that inventors have keen insight into the direction their work is headed, may I present counterpoint evidence No. 1: New Hampshire’s Roger Easton, one of the fathers of GPS satellite navigation.

“I thought it would be useful for camel trains and things like that – the Silk Road,” said Easton, looking back on his pioneering satellite-navigation work at the Naval Research Laboratory a half-century ago. “I never thought it would be used the way it has.”

Camel trains on the Silk Road! Wow, that’s a long way from dashboard-mounted satellite maps for your car.

I talked to Easton last week, while he was in the Washington, D.C., area to be inducted into the National Inventors Hall of Fame.

Easton was honored along with Manchester’s Ralph Baer, who developed the first home video game while working at Sanders Associates in Nashua (now BAE Systems) in the early 1970s.

This isn’t the first time those two have gone to D.C. together to be honored for their work. They were both awarded a national Medal of Technology by President George W. Bush in 2006. (If you’re wondering about Dean Kamen, he got the “twofer” ahead of them: Hall of Fame and Medal of Technology.)

Baer is pretty well-known, has been lionized by computer gamers, mentioned in or has helped write books about the history of this multibillion- dollar field, and the Smithsonian Institution is among several museums that have his papers or early models in their collection.

I’ve written about Baer many times over the past decade, in this column and the GraniteGeek blog. But I had never noticed our link to Easton, who as a father of GPS is definitely an inventor extraordinaire, so I jumped at the chance to talk to him.

Easton, who is 89, developed the essence of global positioning system in a time- honored way: As part of a military contract that was trying to do something else.

He was in the Naval Reserve, working for the Naval Research Laboratory near Washington, D.C., in 1955, when the U.S. was trying to launch satellites into orbit. He and a couple of other engineers were given the task of keeping track of them once they were aloft.

The system was called Minitrack, and after Sputnik scared us silly, Easton extending it to find and follow unknown satellites orbiting Earth. It used interferometry, or patterns made when different signals overlap. Interferometry requires exact knowledge of the time when various signals are sent and a way to communicate that time among various locations. This last point is harder than it sounds, and perfecting it proved crucial to the development of GPS more than a decade later.

“We were not making a navigation system when we started, we were just transmitting the time between transmitter and receiver by way of a satellite,” said Easton.

This led to the realization, he said, that “time would be the fundamental of (a navigation) system.”

“So you solve for four things: for the x, y z (three physical dimensions) and the time, and the time was the essential thing,” he said.

A time-based navigational system with passive ranging, circular orbits, and space-borne clocks synchronized to a master clock – that was his 1970 patent and the heart of GPS, which he spent the rest of his military career expanding and improving.

Speaking as the son of a Marine who grew up amid the friendly (sort of) rivalry among military services, I was tickled at Easton’s response when I asked whether development was prodded by Cold War competition.

“No, the Soviets weren’t working on it, as far as we knew,” he said. “The Air Force was working on it, but they were confused and had it all goofed up. It only worked when they took over the Navy way of doing it.”

It took decades for enough satellites to be launched, technology to be improved, notably through the development of mobile telephones, and the system to be unleashed for civilian use, but as we all know, GPS has become one of the basic technologies of modern society, used for everything from surveying to geo-tagging Flickr photos.

The technology has pretty much grown right out of the original R&D, even if its various uses leave camel trains in the dust.

“We didn’t have the integrated circuits then, and they had as much to do with the development of GPS as did GPS,” he said. “We had no idea that cell phones would take off and would have GPS in them.

“When you figure that’s close to a billion user equipments, that’s kind of mind boggling,” he said.

Indeed it is: Not many inventors can say their work is in so many hands. Easton relocated to Canaan, near where his mother lived, after retiring in 1980.

New Hampshire political watchers may know him from his run for governor in 1986 and his two terms in the state House of Representatives. But the rest of us can think of him every time our dashboard scolds us for turning left instead of right.

David Brooks can be reached at 594-5831 or