Well the most likely explanation would seem to be related to your GPS display routine. If you are getting accurate position information the timing from the satellites must be within a few nanoseconds. The satellite time currently differs from UTC by plus 15 seconds because UTC is retarded by one leap second on a regular basis but the satellite time is not altered. The satellites broadcast this offset from UTC but only every 12.5 minutes. It is not unusual for a GPS display to have a relatively low priority compared to the intensive position calculations and give a time display that differs by a second or two from UTC.
73 Alan ZL2BX -----Original Message----- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Dave Guimont Sent: Thursday, 2 February 2012 18:29 To: Vince Fiscus, KB7ADL Cc: amsat-bb@amsat.org Subject: [amsat-bb] Re: GPS Time observation Interesting question, Vince...am sure someone on here will be able to answer it. I know at one time the civilian population was restricted from the most accurate location, and as I also remember the military accuracy was within a centimeter if several observations were taken...Nice to see your smiling face on here, my friend... Anyone? 73 Dave >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 > >_______________________________________________ >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 73, Dave, WB6LLO dguim...@san.rr.com Disagree: I learn.... Pulling for P3E... _______________________________________________ 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 _______________________________________________ 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
