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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Time and cel nav, a stupid question
From: Fred Hebard
Date: 2008 Apr 22, 12:54 -0400
From: Fred Hebard
Date: 2008 Apr 22, 12:54 -0400
I followed up on this when it was mentioned previously on this list, and I believe the accuracy of cell phones may vary with the network. I'm on AT&T, and my impression is that the time is not accurate. For instance, my phone now says it's 9:51:55 and my computer says it's 12:52:42. The computer is getting its time from a network time server. These may be more accurate than the USNO site, but, I don't know this one way or another. Fred Hebard On Apr 22, 2008, at 11:56 AM, Lu Abel wrote: > > Bill: > > The time difference between your Garmin and the USNO web site is > likely > due to network delays (ie, the USNO sends you a time pulse at the > correct time, but it takes almost a second to arrive at your > computer). The other web site run by USNO, www.time.gov, says it > attempts to measure network delays and compensate for them. Another > source for accurate time is your cell phone. Mine only keeps time to > the minute, but it very accurately rolls over at the 60-second mark. > > Lu Abel > > Bill wrote: >> The current discussion on time, relativity and leap seconds is, in >> many >> areas, well above my head. Noting the various flavors of UT >> (currently), an >> observation and a pragmatic question for cel nav. >> >> The seconds readout between my GPS (Garmin GPS 76) and >> http://tycho.usno.navy.mil/cgi-bin/anim >> differ by about one (1) second. >> >> The web site (dial up modem at the moment) is nominally one (1) >> second >> behind the GPS readout. >> >> Bringing it into the realm of traditional navigation, which time >> do I use to >> set my hack watch? ;-) Potentially a quarter mile intercept >> difference >> under ideal circumstances. >> >> I do not have access to a time-signal radio now. >> >> Bill >> >> >>> >> > > > --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---