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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: 3 Lop's
From: Bill Noyce
Date: 2004 Nov 15, 11:51 -0500
From: Bill Noyce
Date: 2004 Nov 15, 11:51 -0500
Frank Reed wrote: > Regarding the three LOP fix, clearly if all altitudes are > displaced by 3 minutes of arc, the vessel's most likely > position would be the center of the triangle rather than > one of the vertices. This is true if the bodies observed differ in azimuth by 120 degrees. But if the bodies' azimuths differ by 60 degrees, and you have the same systematic 3 minute error, you'll get a very similar-looking figure, but your true position would be outside the triangle. And, as discussed ad nauseum here not too long ago, if your observation has random errors (and no systematic errors), then your true position is quite likely to be outside the triangle, even though the "Most Probable Position" -- the peak of the probability density surface -- is indeed inside. -- Bill