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: Advancing LOPs for precision fixes
    From: Andrés Ruiz
    Date: 2010 Feb 18, 12:01 +0100

    At my web page my article:
    "Celestial Fix Nautical Almanac Sight Reduction algorithm for n LoPs", gives a 
    detailed information of the algorithm.
    
    Originally the references are:
    * Optimal Estimation of a Multi-Star Fix, C. De Wit. NAVIGATION, Vol.21 , No. 4, Winter 1974-
    75, pp 320-325
    * Compact Data for Navigation and Astronomy for the Years 1991-1995, Cambridge University
    Press ISBN 0-521-38731-0. Yallop B. D. and Hohenkerk C. Y. (1991).
    * The Nautical Almanac. USNO
    
    Also the free program "CelestialFix.exe" implements the method, see pic.
    
    Regards,
    
    Andrés Ruiz
    Navigational Algorithms
    https://sites.google.com/site/navigationalalgorithms/
    
    
    -----Mensaje original-----
    De: navlist-bounce@fer3.com [mailto:navlist-bounce@fer3.com] En nombre de Gary LaPook
    Enviado el: jueves, 18 de febrero de 2010 11:41
    Para: NavList@fer3.com
    Asunto: [NavList] Re: Advancing LOPs for precision fixes
    
    Have you tried using the method in the N.A. to which you refer? I may be 
    missing something but I don't see anywhere in the given formulas where 
    you input course and speed which would be necessary if the method was 
    allowing for advancing the LOPs to a common time.
    
    gl
    
    
    P H wrote:
    > As John Karl writes in his book:
    > "The Nautical Almanac gives an iterative procedure for calculating a 
    > fix from several intercepts and azimuths determined from their St. 
    > Hilaire sight reductions."
    >
    > I would add that this procedure does take the vessel motion (assumed 
    > to be constant during the round of observations) into account.  I am 
    > confident that I am simply restating a fact that is well-known among 
    > NavList members.  Also, I think it is not unreasonable to assume that 
    > the content of the Nautical Almanac reflects common (standard, 
    > recommended, accepted, etc.) practice.
    >
    >
    > Peter Hakel
    >
    >
    > ------------------------------------------------------------------------
    > *From:* hch 
    > *To:* NavList@fer3.com
    > *Sent:* Tue, February 16, 2010 8:20:41 AM
    > *Subject:* [NavList] Re: Advancing LOPs for precision fixes
    >
    > Gary,
    >  
    > You said ... "It is common practice to ignore the movement of the ship 
    > during the time period needed to take a round of sights ...", and I 
    > am unable to dispute this assertion in the light of today's "it's good 
    > enough" approach to Celestial Navigation. I can, however, state in no 
    > uncertain terms that this was not the traditional approach - LOPs 
    > generated in a round of sights were always advanced or retarted to a 
    > common time, so long as the distance run between individual sights was 
    > measurable, if for no other reason than professional pride.
    >  
    > Regards,
    >  
    > Henry
    >
    >
    
    
    
    
    
    
    
    

    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