List: trawlers@lists.trawlering.com
From: tonymarshall@hargray.com
TWL: GPS & autopilots
Sat, Apr 28, 2001 4:33 PM
It seems clear to me, based on my limited understanding of
all position finding systems from celestial to GPS, that the only way I
can know (not estimate) my ship's heading is by reference to a magnetic
or gyro compass, or by measuring the relative bearing of the sun or
other celestial objects.