Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    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

    Visit our website

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

    > There are probably as many definitions of "Estimated Position" as
    > there are navigational texts. The Navigation Dictionary, once
    > published by the US Navy Hydrographic Office as HO 220
    > 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
    > >
    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site