NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: GPS as a time authority
From: C Sellars
Date: 2009 Sep 15, 13:06 -0700
From: C Sellars
Date: 2009 Sep 15, 13:06 -0700
Hi John, I wear a Casio model 3089 that recieves a time calibration signal from Fort Collins ( for the US )and updates its time setting accordingly. I have owned this watch for 6 months and am constantly checking it against my Garmin 12xl gps time. I have never seen even a second differance. I am assuming my GPS must be doing the calculations necessary to give me UTC. We also use the GPS time for racing sailboats. This watch is amasing, I have not had to manualy set it since it was purchased. Chris Sellars On Sep 14, 9:05�am,wrote: > I think this has been dicussed before, but I'd like to be refreshed on the list's opinion: > > While assisting the Race Committee at a regatta this weekend, I heard the timekeepers say that they were using "GPS time." �I noted that my $79 wristwatch, which I check monthly against the US Bureau of Standards atomic clock (ph: 303-499-7111) and which doesn't lose a second per month, was 8 seconds ahead of the Committee's time. > > I later checked the time shown on my hand-held Gartmin GPS receiver, and it agreed with my watch. �The watch was also still in sync with the Bureau's atomic clock. > > Question: �Is the time displayed by GPS receivers considered a reliable and spot-on source, up to the requirements of accurate celnav? �I would think that it would be, since the GPS network depends on accurate tracking of the satellites' position at a given time, yet there was that 8-second discrepancy. �Perhaps the Race Committee were simply careless about setting theior clockby GPS. > > Any thoughts, List Members? > > -John Parsons --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---