NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: digital compass, etc
From: Patrick McVey
Date: 2000 Sep 07, 9:40 AM
From: Patrick McVey
Date: 2000 Sep 07, 9:40 AM
I don't mind though slightly off subject. You're doing what's called, "swinging the compass." The sensor (fluxgate I believe) and microprocessor are testing the sensitivity of all 360 degrees and making a correction table for each point of the compass (probably all 360 points). The sensitivity varies due to large pieces of magnetic material on your vessel and their ability to influence the compass sensor. The guy called the compass adjuster does this as a service for a boat owner. He can move some axially located magnets inside the compass housing to compensate for errors around the circle. And because reality is analog, one gets different readings going clockwise and counterclockwise. So he does both and averages. But he can't compensate all of it so he gives you a correction table. Then, when you use your compass for a reading you have to plus or minus the correction depending on which bearing you are making. I usually blow off the small error and make a note to myself to ve! rify course by some other means. But hey, your chip is doing all that. We're all just a dead battery from the stone age. >>> s.ellis11@GTE.NET 9/7/2000 12:57:35 PM >>> Hi I am new here, and I was wondering if anyone here has experience using a digital or analog compasses. You see I just installed a digital compass in my car; a Ford Escort station wagon. The instructions say to calibrate the compass, you have to press a button, then drive around in a circle twice, stop, then do another 2 circles. I did that and the readings seem accurate. The compass is so-called "V1000 Copilot" How do I know the readings I receive are exactly correct? Of course I know generally which way I'm going (NSEW)and as I turn my car the readout seems to turn accordingly (if I turn 5 degrees left the readout should show that) I realize this may not be the right list to post this question, but if you could refer me to another list or answer this question I would appreciate it. Thank you. Stephen