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Re: Definition of estimated position?
From: Joel Jacobs
Date: 2004 Sep 27, 16:40 +0000

I would like to add that the DR should be corrected for current and LEEWAY in arriving at the the EP.

Joel Jacobs

--
http://www.landandseacollection.com

-------------- Original message from "Henry C. Halboth" : --------------

> There are probably as many definitions of "Estimated Position" as
> summarizes American definitions about as well as anyone can,
> and as follows ...
>
> "Estimated Position = The most probable position of a craft
> determined from incomplete data or data of questionable accuracy.
> Such a position might be determined by applying a correction
> to the dead reckoning position, as for estimated current; by plotting
> a line of soundings; by dropping a perpendicular from a dead
> reckoning position or previously estimated position to a single line
> of position; or by plotting lines of po! sition of questionable accuracy.
> If no better information is available, a dead reckoning position is an
> estimated position, but the expression estimated position is not
> customarily used in this case. The distinction between an estimated
> position and a fix or running fix is a matter of judgement."
>
> In the context of your question, the estimated position probably sought
> is the intersection of the body's azimuth with the LOP at the intercept
> distance or, in other words, dropping a perpendicular from the DR
> position to the LOP. This was the accepted definition many years ago -
> a differentiation, however, being made to insure use of the DR position,
> as opposed to the assumed position employed in many of the short
> tabular methods. In using the time sight, the estimated position would be
>
> the intersection of the longitude calculated with the latitude used in > the
> calculation - also a point on the LOP established - remember Sumner
>
> On Sun, 26 Sep 2004 16:35:35 -0300 Jim Thompson
> writes:
> > > -----Original Message-----
> > > From: Navigation Mailing List on Behalf Of Russell Sher
> > > A navigational problem in the Jan/Febr. 2004 edition of Ocean
> > > Navigator Magazine (#135) posed a question which involved a
> > > navigator shooting the sun to obtain an LOP. Since there is only
> > > one LOP there is therefore no fix, but the one of questions asked
> > > is �What is the Estimated Position?� I imagine that it is the
> > > position plotted on the LOP as being the closest from the DR.
> > > Does anyone agree?
> >
> > That is how it is taught in the Power and Sail Squadrons' CN course
> > -- the
> > point on the L! OP perpendicular from the LOP to the DR position.
> > http://jimthompson.net/boating/CelestialNav/CelestNotes/Plotting.htm
> >
> > Jim Thompson
> >
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