The difference between GPS time and UTC is adjusted as necessary. The adjustments come in the form of leap seconds and are added when needed at the end of June or December. The difference between GPS time and UTC is currently 15 seconds. There will be a leap second added this coming June 30. What is being seen is the casual user GPS receiver software does not put a high priority on time display.
John WA4WDL
-------------------------------------------------- From: "Jim Jerzycke" kq6ea@verizon.net Sent: Thursday, February 02, 2012 3:18 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: GPS Time observation
I think this has something to do with "GPS Time" vs "Earth Time".
IIRC, GPS time doesn't take into account the Leap Seconds that have been added to Earth time since the first GPS satellites have been launched. I think some of the newer receivers can compensate for this, but I'm not sure.
It's been about 14 years since I last worked in the GPS industry, and I'm a bit rusty on all the new stuff!
73, Jim KQ6EA
On 02/02/2012 04:57 PM, George and Cheryl Abbott wrote:
I'm not sure about GPS,but I have noticed that the clock on our cable box is off by up to 4 seconds at times.Customer service was not aware or concerned when I let them know.
-----Original Message----- From: Vince Fiscus, KB7ADL Sent: Thursday, February 02, 2012 10:28 AM To: amsat-bb@amsat.org Subject: [amsat-bb] GPS Time observation
I have an old GPS unit, a Magellan explorist 210. It's fairly accurate determining position. After it has acquired about eight to ten satellites the position error averages between 20 to 35 feet. Now the question, the other day I was looking at one of the information pages the unit can display and on it, it gives the time in UTC. Just for fun I thought I would see how close the time was to WWV. I was surprised to see the unit was between one to four seconds off over various tests compared to WWV. IS this typical of all GPS units or do some display the time of day more accurately?
KB7ADL
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Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb