Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Why Not To Teach Running Fixes
    From: Andrés Ruiz
    Date: 2009 Dec 16, 09:06 +0100

    In celestial navigation two motions are involved:

    • The relative motion of the observed celestial body
    • The motion of the observer

     

    At sea there are some uncertainties, in navigation –coastal or celestial– in order to get a fix:

    • Initial position of the observer
    • Course and speed

    and are interrelated.  In CelestialFix.exe the process for obtaining a running fix is iterative and based in two rotations to move the CoP. But when using Kaplan’s method the motion of the observer is part of the calculation, like in a lot of engineering models.

     

    The traditional Running Fix treatment is an approximation of the whole problem, but enough for practical purposes. Is the one a navigator always must know. “RFix animation.ppt” by Lu Abel is very didactical. Thanks. Yes, I say: “Teach Running Fixes”

    In an astronomy course, the speaker comparing the stars with lighthouses in the sky and this gave me the idea to write the article: “Fundamentos de la Navegacion Astronomica.pdf” to explain what is a celestial fix.

     

    A good review is available online http://aa.usno.navy.mil/publications/docs/reports: "The Motion of the Observer in Celestial Navigation". Kaplan, G. H. (1996), Navigator's Newsletter, Issue 51 (Spring 1996), pp. 10-14. Acrobat logoPDF (113K) or PostScript (100K).

     

    Andrés Ruiz

    Navigational Algorithms

    http://www.geocities.com/andresruizgonzalez

     

     

     

    -----Mensaje original-----
    De: navlist@fer3.com [mailto:navlist@fer3.com] En nombre de John Karl
    Enviado el: domingo, 13 de diciembre de 2009 17:25
    Para: NavList@fer3.com
    Asunto: [NavList 11116] Why Not To Teach Running Fixes

     

    Ah, the traditions of the sea.

     

    For all the talk on how to teach running fixes, here's my 2 cents 

    worth on why to not teach them at all -- they make no sense whatsoever.

     

    The figure below shows that they operate under extremely ridiculous 

    assumptions: They assume that the estimated DR track perpendicular to 

    LOP1 is completely accurate and that the DR component parallel to LOP1 

    is completely without value.  Can anyone on the List justify these two 

    assumptions??

     

    I recommend using the Estimated Position (EP) concept shown in the 

    figure.  It fully honors the new LOP2 while retaining the information 

    in the DR that is not contradicted by LOP2.

     

    JK

     

    --
    NavList message boards: www.fer3.com/arc
    Or post by email to: NavList@fer3.com
    To unsubscribe, email NavList+unsubscribe@fer3.com

    --
    NavList message boards: www.fer3.com/arc
    Or post by email to: NavList@fer3.com
    To unsubscribe, email NavList+unsubscribe@fer3.com

    File:


    File:

      
       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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