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    Re: No Two-Body Fix Problems
    From: Peter Hakel
    Date: 2009 Nov 5, 17:50 -0800
    This is my thinking exactly, please see the attached spreadsheet.
    There are some highly specialized arrangements with which it can have problems,
    but it should work fine for any "normal" case.

    The preloaded case is rotated 90 degrees from W to S with respect to my original illustration example.
    Thus it has the GP1, GP2, and the ship on the same meridian, with osculating LOPs.


    Peter Hakel


    From: John Karl <jhkarl---.net>
    To: NavList <navlist@fer3.com>
    Sent: Thu, November 5, 2009 9:35:51 AM
    Subject: [NavList 10464] No Two-Body Fix Problems


    I'm starting a new thread (I think it's called) because the "Two Body
    Fix Caveat" seems to have gotten off topic.

    As I posted on the other thread, It seems to me that if the computer
    code simply calculates the answers for the two possibles fixes, using A
    +B and A-B in Eq. 7.5d, and then lets the navigator pick the closest
    fix, all possible combinations of the locations of the GPs and ship
    are covered.

    And I don't see any problem with the ship being on, or near, GP1's
    meridian.  This is a well defined problem with no ambiguity in the
    equations, and the navigator doesn't need to know his position
    relative to the meridian.

    Computing both fixes makes the program's inputs and outputs very
    logical and straightforward.  After all, there are two fixes in the
    solution and the navigator must, indeed, select the proper one.

    Those interested might want to check this out to see if I'm right,

    John


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