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    Re: Rejecting outliers: was: Kurtosis.
    From: Antoine Couëtte
    Date: 2011 Jan 1, 12:08 -0800

    RE : http://www.fer3.com/arc/m2.aspx?i=115097
    [NavList] Re: Rejecting outliers: was: Kurtosis.
    From: glapook---net
    Date: 1 Jan 2011 10:24

    Hello Gary,


    Happy New Year 2011 to yourself and to your Spouse !

    *******

    I got general mathematical training at the French Naval Academy (1972-1975) about Least Square Methods. As I can recall this was part of our general Engineer's Statistics Course and not any specific part of our Navigation Program. Therefore : NO mention then whatsoever in my Naval Academy Navigation Course about any "Symmedian point". Now things have changed obviously regarding the practical interest and use of Statistics as directly applicable to Navigation, but I doubt whether we could find there a specific mention of our now dear "Symmedian point", although it is computed nowadays by Least Square Methods.

    *******

    During my exchange tour in the US Navy (1980-1983) as an Aircraft Carrier Pilot, I read a wonderful Book "Calculator Navigation" (ISBN # 0-393-03192-6 , NORTON 5-79) by M. Mortimer Rogoff - whom I congratulate if he ever happens to read these lines - which CONVINCED me about the exceptional interest of using such previously learnt and practiced "general" atistical methods to get the most of a set of CelNav observations.

    I purchased a HP41CX in late 1980(see the whole "story" here : http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv016.cgi?read=91719). Therefore in early 1981 I established for my own use the LOP's Least Square equations - with some help at the beginning from Dr. Jerry Alderman for the LOP's (thanks again Jerry if your read me!) - as well as the full (7th order) LAN's Least Square equations which I both programmed on my HP41. Although "starting" from a quite different mathematical view-point, LAN's data processing yields exactly the same end results than conventional LOP's if and when - just for fun - I am to treat a full LAN data set just like any conventional set of LOP's.

    (As a most recent example see :

    [NavList] Re: Ex-Meridian Exercise
    From: antoine.m.couette---fr
    Date: 28 Dec 2010 00:29
    http://www.fer3.com/arc/m2.aspx?i=115000&y=201012)

    *******

    Now , as regards such Least Square Methods as applied to LOP's, I totally ignored - until a few weeks ago - that the CelNav Fixes I have been using and which I had been computing and submitting to my Aircraft Carrier Skippers ( "heavy" USN and FN Captains then of course ... ) were such "magic" points as nowadays called "Symmedian Points".

    We never stop learning , don't we ?

    See you again in 2011 ?


    Best Regards

    Kermit

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