NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: sight reduction with GPS receiver
From: Bill B
Date: 2005 Mar 21, 23:03 -0500
From: Bill B
Date: 2005 Mar 21, 23:03 -0500
Frank Clever thinking. My Garmin 76 will not accept 90d north or south for whatever reason, but will take 89d 59!999, a scant 6.076 feet away and beyond the resolution of the unit. Hence used a difference of 89d 59!999 along the equator and to the pole from 000d 00!000. Results: 5401 nm equator to pole 5410 nm along the equator So it looks like it is calculating ellipsoidal, but not as well as Paul's unit. (2229 on mine vs. 2232 on Paul's in his example) Perhaps time for a firmware update? Would appreciate knowing what other folks obtain with the same unit and recent firmware. Bill > By the way, I should have thought of this earlier, there is a simple test for > ellipsoidal versus spherical distances. Set the device to calculate the > distance between Lat,Lon of 0,0 and 0,90 (both points on the equator). Then > calculate the distance between Lat,Lon 0,0 and 90,0 (along the Greenwich > meridian to the North Pole). If the calculation is spherical, the distances > will be the same. >
