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: Systematic Error (LOPs revisited)
    From: Peter Fogg
    Date: 2003 May 29, 10:27 +1000

    Bill's on the money! It seems to me that this is the key to understanding
    the whole process. Any number of intersecting LOPs are a succession of
    intersections involving 2 lines. With a triangle there are 3 bisectors of
    these 3 intersections, when extended they meet at a point. Keep going ...
    
    Sorry about the "quadrant" error. My understanding was that this means an
    area divided into 4 parts but it seems that it only refers to 4 equal parts.
    You live and (hopefully) learn ...
    
    George Bennett has flown the coop, flying out today. By co-incidence, I
    shall soon be following in the same general direction, off to France for
    most of June to visit family, although I am also looking forward to renewing
    my aquaintance with the northern celestial sphere. My extended family, if
    you will ...
    
    I don't think this is altogether a bad thing. Anybody interested in this
    technique needs time to draw his own diagrams and think about them. I know
    only too well from experience that learning new and unfamiliar ideas can be
    a painful, slow, and frustrating process. Just as well its worth it, apart
    from anything else it keeps our brains young.
    
    
    
    ----- Original Message -----
    From: "Noyce, Bill" 
    To: 
    Sent: Thursday, May 29, 2003 1:23 AM
    Subject: Re: Systematic Error (LOPs revisited)
    
    
    > Peter Fogg:
    > > >Lets start with those 2 intersecting LOPs. If there is a systematic
    error
    > > >then it will be either towards the direction of the 2 azimuths or away.
    >
    > George Huxtable:
    > > Sorry, but I'm lost already. Presumably Peter is discussing here LOPs
    from
    > > compass bearings of landmarks.
    >
    > I think the later discussion makes clear that Peter is discussing
    > LOP's from celestial observations.  In that case, if you draw
    > an arrow from each LOP, toward the body observed, then one "quadrant"
    > has both arrows pointing to it, one has both arrows pointing away,
    > and two "quadrants" have a mismatch.  If the errors in the two
    > observations have the same sign, then the true position must be
    > in one of the two matching quadrants; if the errors are equal,
    > the true position must be on the angle bisector that passes through
    > these two quadrants.
    >
    > Of course, in the two-observation case, there's no information to
    > estimate whether systematic errors are likely.
    >
    >         -- Bill
    >
    
    
    

       
    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