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December 31, 2018

"Getting There" - The Story of GPS

Why is it that men have a reputation for never asking for directions, even when they’re lost?  Is it because they’re macho, or just don’t like maps?  Why do we enjoy the hunt over finding the prize?

Well, that debate has been made moot by technology thanks to the invention of GPS… the Global Positioning System.  You probably have one in your car and on your phone and depend on it exclusively to get where you’re going.

The history of GPS isn’t that old, but it is fascinating.

Back in 1973 the US Department of Defense launched the first of what would become a fleet of 31 satellites circling 12,550 miles above the globe.  Each satellite has a built-in atomic clock, synchronized with the ground station and the other satellites. The satellites constantly transmit data about their time and location, and GPS “receivers” (in your car and smart-phone) pick up the signals from at least four satellites to compute your location.

Initially the GPS system was only for military use.  But after Korean Airlines flight 007 was shot down for straying into Russian airspace, President Reagan issued an order making the system available for civilians.

In 2000 President Clinton enhanced the order, making GPS even more sensitive to your exact location.  Today the most accurate GPS receivers (used on aircraft) can tell you where you are to an accuracy of 3.5 meters.

That’s when commercialization took off, though the first portable GPS receivers weighed 1.5 pounds, could only run on batteries for two hours and cost $3000.

Cellphone manufacturers started offering built-in GPS starting in the late 1990’s and in 2002 the FCC mandated the system be built into cell-towers to be able to triangulate a user calling 911. 

The US military relies on built-in GPS to guide weapons to their targets. But the civilian benefits of this technology range from mapping to disaster relief.  And, of course, self-driving cars.

Another popular commercial application of GPS is “fleet management”.  GPS-equipped cars and trucks can constantly be monitored at the head office so dispatchers can tell who’s on the job and who’s taking an extended break.

Law enforcement also uses GPS.  A commercial device called Stingray can ping any phone and get it to transmit its location.  According to the ACLU, 75 law enforcement agencies in 27 states use Stingray.  But in Connecticut, they first need a warrant.

Not to be outdone, the Russians, EU, India and Japan also have their own GPS systems.  Adding the Russian GLONASS system to our GPS can increase its accuracy to 2 meters. A separate Chinese GPS system, Beidou, will be operational globally by 2020.

But all of this tech is not foolproof.  Homeland Security worries about GPS spoofing and jamming.  Though prohibited by law, a $33 GPS jamming device has been used to interfere with location tracking at such sensitive locations as US airports.

And in an era when killer satellites can blast a GPS bird in outer space, one worries how vulnerable we are in a time of war when zapping just four US GPS satellites could cripple our system.

So as you wend your way over hill and dale to Grandma’s house for the holidays, you might just want to keep an old-school paper map in your glove compartment.

Posted with permission of Hearst CT Media


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