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    Re: Need help writing a slope-fit excel sheet
    From: Greg Licfi
    Date: 2014 Jan 25, 00:19 -0500
    Thanks Peter,
    FYI: I attached the article I was referring to.
    ~Greg

    On 01/24/2014 10:58 PM, Peter Hakel wrote:

    Hello Greg,

    Please take a look at these links:

    http://www.navigation-spreadsheets.com/alt_corr.html#average1
    http://www.navigation-spreadsheets.com/alt_corr.html#average2

    What I describe there is different, because in my spreadsheets the fits are computed rather than guided by eye looking at a plot.  Nevertheless, it is related to what you are trying to do, so you may find it useful.

    A few years ago we had extensive discussions on NavList about precisely this topic.  You may use NavList's search engine (thanks, Frank!) to look for threads named "Kurtosis", "Weighted least squares", and "Rejecting outliers" which started around December 2010.


    Peter Hakel


    From: Greg Licfi <cfi{at}licfi.com>
    To: pmh099---.com
    Sent: Friday, January 24, 2014 6:03 PM
    Subject: [NavList] Need help writing a slope-fit excel sheet


    Hi all,
          I read a article by David Burch concerning sight averaging with (I
    believe) the intent on improving
    the sights taken with plastic sextants. Mr. Burch believes that this
    technique should be applied to metal
    sextants to improve overall accuracy. One of the things he suggested is
    doing a slope-fit of the multiple
    sight data to kick out not-so-obviously-bad data points. It all makes
    sense to me. I started to write a slope-fit
    excel sheet (which eventually I can use on my smart phone) There are two
    plots: one is the sight data
    in BLUE, the second is a Hc for the start & stop times of the sights it
    is in RED. ultimately you will be able to
    slide the RED Hc plot up or down to see if the sight data points fit the
    slope. I'm stuck getting the buttons
    to work. I would ask if there are any excel mavens on the list if they
    could look at my attached sheet and
    help me activate the cursor up/down buttons; I'm not super knowledgeable
    on macros. Once that is figured
    out it should be quite handy for isolating bad sights.
    Many Thanks In Advance!
    ~Greg
    
    P.S.
    Typically how many sights on average should one take, and over what time
    span?
    
    
    Attached File:

    (img/126689.slope fit.xls: Open and save or View online)

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=126689


    View and reply to this message: http://fer3.com/arc/m2.aspx?i=126691


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