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: Still on LOP's (mea culpa)
    From: Michael Wescott
    Date: 2002 Apr 26, 00:48 -0400

    I wrote:
    
    > Sorry, but Steven Tripp's calculations don't find the MPP. They find
    > the least squares point, a computationally more tractable exercise and
    > in this case, they aren't the same.
    
    And I was wrong.
    
    So much for my credentials ...
    
    Given that each observation comes from the same Gaussian distribution
    the joint probability density is proportional to
    
            exp( -(d1**2 + d2**2 + d3**2 ... ))
    
    where dn is the distance from a point to LOP number n. So it's
    a matter of minimizing d1**2 + d2**2 + d3**2 ...  to get maximum
    joint prob density or MPP. In other words it's a least squares problem.
    
    So Steven Tripp, Trevor Kenchington et al. were correct that the MPP is
    not the center of the inscribed circle.
    
    I still wonder what the Nautical Almanac meant in that article ...
    --
            Mike Wescott
            Wescott_Mike{at}EMC.COM
    
    
    

       
    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