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    Re: Running Fix vs Estimated Position -- Monte Carlo assessment
    From: Joe Schultz
    Date: 2010 Jan 11, 21:16 -0800

    waldendand, thank you. Here's something we can debate - the last series of "just believe me" didn't cut it, in my opinion.

    First the questions:
    1) please define "estimated position" and how you obtain it.
    2) what is jkarl-001.jpg? Is this your "Next, is a scatter plot showing error in nautical miles as a function of crossing angle between LOP's."??
    3) Are the two plots in jkarl-002.jpg the same plot with a different longitude scaling? I'm assuming the axes are LAT/LON.
    4) please define your LOP Zn. The plots don't make sense with your first and second LOP Zn, as compared to the 77.3 and 125.0 listed.
    5) what is your "Error in initial DR postion: +/- 3 nautical miles along LOP1, uniformly distributed randomly."??

    Then my initial observations/conflicts:
    1) relationship between ship's course and LOPs will affect the conclusions. I think your assumption isn't quite correct.
    2) I'm not so sure of the validity of your result when you start the exercise with a "true starting position" that lies on the first LOP. It looks like you're running from a FIX - we normally run a LOP when we don't know where we are on the LOP.

    Give me a couple days after you respond - I think you'll then have enough information for me to play with. In the meantime (after your response), why don't you give the exercise I posted a try (post 11436 on 05Jan2010)? Not knowing where we are on the first LOP is more realistic, in my opinion.

    In the meantime I'll do a short write-up on the uncertainty in a DR or EP (using my definition of an EP). May give you some additional thinking to do.


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