It’s Time for GPS Accuracy (give or take 15 seconds)
While working with one of our technical “geeks” here at the TrackerSystems.net Tech Bench and Gambling Casino (just kidding about the casino) I was offered what I thought was a sucker’s bet. I said that the GPS time clocks in the GPS Satellites are so accurate that they are within a nano-second of UTC time as measured by the National Bureau of Standards. These satellite clocks then adjust the clocks in our GPS Vehicle Tracking Devices. To my surprise, the Captain offered that the GPS time was over TEN SECONDS off from UTC time. I said that was impossible – I had read that they were atomic clocks matched up to a land-based reference clock. So, I took the bet… and lost. Here’s why: GPS Time does not “honor” leap seconds – the adjustment added to “human” UTC time every so often to account for the earth’s rotation slowing down. So, in the years since the GPS clock was started, UTC time has slowed down so that it lags GPS time by 15 seconds today. What’s more, the LORAN-C (the maritime radio-navigation system that preceeded GPS) clock, started years before GPS, is 24 seconds ahead of UTC time.
Here’s a neat link to a comparison clock: http://leapsecond.com/java/gpsclock.htm
