NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Still on LOP's
From: Peter Fogg
Date: 2002 May 23, 09:33 +1000
From: Peter Fogg
Date: 2002 May 23, 09:33 +1000
WSMurdoch@AOL.COM wrote: 'Systematic errors expand some cocked hats and contract others.' One error is built into our system, and that is that our LOPs are drawn as straight lines, whereas they are really arcs, portions of circles. The further the hat is from the intersection of the LOP and the azimuth line the more pronounced this error will be. Also, the further the fix position is from the DR the longer will be the intercepts, and the less likely it is to be accurate. The solution to both (and indeed generally helpful with regard to errors?) is to redo the sight reduction process ( its as easy as checking it carefully !) using the initial fix position as the new DR. In theory this could be done indefinitely, but the Law of Diminishing Returns means that you quickly (once or twice) exhaust its usefulness.