NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: GPS vs WWV time.
From: Paul Hirose
Date: 2001 Sep 03, 6:38 PM
From: Paul Hirose
Date: 2001 Sep 03, 6:38 PM
Yes, there can be an obvious (to the eye) inaccuracy in the time displayed on a GPS receiver. My Magellan Trailblazer is sometimes a full second off compared to WWV time ticks. I've heard of others being several seconds off. After all, the receiver's main job is computing position, so updating the time display has low priority. There's also the offset between UTC and GPS time to consider. GPS time never has leap seconds, so the two time scales have diverged by a few seconds by now. However, the offset is encoded in the GPS signal, and as far as I know all but the really obsolete receivers make the correction. My old Magellan is a '94 model and it keeps up with the leap seconds. I guess all you can do is repeatedly test your receiver against WWV until you get its behavior pinned down. You may want to ask on the sci.geo.satellite-nav newsgroup. -- paulhirose@earthlink.net (Paul Hirose)
