NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Fluxgate compass
From: Brian Whatcott
Date: 2002 Jan 29, 5:06 PM
From: Brian Whatcott
Date: 2002 Jan 29, 5:06 PM
At 12:17 PM 1/29/02, you wrote: >On my boat the installer of the fluxgate compasses spent quite some >time looking for places in the boat which were as far away from >metal as possible in which to install them, but no extra compensating >magnets were used. Of course my boat was fiberglass hulled so it >was not too big of a problem... > >Dan Some more thoughts on fluxgates. Autocorrection firmware cannot deal with two pathological cases: 1) no change in magnetic field vector while the ship's head changes. 2) an opposite change in magnetic field for some change in ship's head. While both of these conditions must be rare, and perhaps 2) never occurs in practise, it's easy to see that a diminished change in magnetic field direction for some particular heading change leads to a loss of precision in the indication. Purely a theoretical speculation: three axes of measurement would provide a definitive value for the field. I suppose that commercial fluxgates measure in two horizontal axes - which still leaves room for some deviation with roll and pitch where the magnetic field dips, as it does in many waters of marine interest, I imagine. Brian Whatcott Altus OK Eureka!