NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: GPS and Great Circle
From: Pierre Boucher
Date: 2002 Oct 8, 22:26 -0400
From: Pierre Boucher
Date: 2002 Oct 8, 22:26 -0400
Hi Jo, Try this: Simulate a route from 45dN, 179d 59.999W (or E) to 45dN, 000 00.000E or W (probably E by your GPS default setting) and you should get a 000T course and 5400 nautical miles distance proving that GPS are computing Great Circles. This will work with any points 180d apart in lalitude North or South of the equator but it is obvious at higher latitude. If you wonder why not 180dW or E, try it on your machine (GPS). There is a chance that the unit won't take it. Pierre Boucher >I am a lurker in this group and actually know only a smidge celestial >navigation. I hope my question is not out of place here. I am curious >whether my GPS follows the great circle route or Mercator rumb line when >plotting long distance courses? >Thanks for patience with the dummy, >Joe...