Years ago, I was visiting my friends Jim and Jamie in their new home in the Edna Valley, just outside of San Luis Obispo. They had moved up here from Orange County and built a home that overlooked the sprawling vineyards.
That Saturday, Jim told me we were going to dinner at Giuseppe's in Pismo Beach, and we'd be joined by their neighbors Brad and Ginny Parkinson. Jim warned me that Brad was a genius who was the father of GPS and I might have trouble keeping up with him. But I was intrigued and ready to be wowed.
When I inquired, Brad dove right into an in-depth explanation of the GPS system. I knew the basics - it relies on satellites in geosynchronous orbits. But Brad went way deeper, laying out the mind-bending complexities involved.
He explained how each satellite is constantly drifting from its ideal position or orbit, with servos occasionally firing to nudge it back. And this was happening with all 24 GPS satellites simultaneously, while the entire Earth was ever-so-slightly wobbling on its axis as the whole lot was hurtling through space.
On top of that, Brad said they had to account for Einstein's two theories of relativity to account for other errors. "It's not the measured accuracy, but the prediction forward that's the real challenge," he said, his eyes burning with intensity.
I was captivated as Brad described the herculean efforts required to develop GPS in the early 70s - the government, military, aerospace companies, and private contractors all working together. Brad, a graduate of the Naval Academy with a MS from MIT and a PhD from Stanford, assembled and ran the team. He was the one who kept it from spiraling out of control. It was deemed successful when they got the accuracy down to 3 meters (10 feet). Nowadays it's accurate to millimeters.
When GPS first launched, the receivers cost a staggering $219,000 (approx. 1.7 million in today's dollars). Now a GPS chip costs about $1.50. The global GPS market has exploded, now worth $76 billion and projected to hit $146 billion by 2030. It's embedded in everything from cars to smartphones and watches to precision farming equipment.
As Brad talked, I was struck by the sheer scale and complexity of this invisible infrastructure that underpins so much of modern life. It was humbling and awe-inspiring to get a glimpse behind the curtain.
But what really fascinated me was finding out Brad was also the father of a system every combat veteran appreciates. Before the GPS project, Brad was in Vietnam developing the AC-130 “Spooky” gunship. Take a huge transport aircraft that's usually delivering supplies and ammunition and convert it into a flying platform with 25mm Gatling guns firing as many as 6,000 rounds a minute – putting a round into each square foot of a football field in mere seconds.
Today's AC-130U is controlled by GPS.
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