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    Re: flabbergasted by gps
    From: Richard B. Langley
    Date: 2011 Feb 22, 14:59 -0400

    GPS receivers can compute position and velocity updates at rates of 1
    Hz or more. Velocity is determined from Doppler-shift measurements and
    so are quite precise (and accurate).
    -- Richard Langley
    On 22-Feb-11, at 2:45 PM, Patrick Goold wrote:
    > I put down my calculator and my almanac on Sunday and went sailing.
    > I had spent spent several hours that morning reducing and plotting a
    > series of sunsights taken the day before,  preparing to ease myself
    > into the arcana of running fixes.
    > Just past the coal dock in Norfolk harbor, I was tinkering with the
    > sail trim. I asked my wife to watch the handheld gps to see if my
    > adjustments made any difference in our speed.  We were loping along
    > at 4 knots.  She was at the stern, I was in the front of the
    > cockpit.  I asked her to hand me the unit.   When she did, just for
    > a second, it registered our speed over the ground as 6 knots.  I
    > could not believe that satellite info was refreshed so frequently
    > that the unit would detect the increased velocity northward as it
    > was passed from hand to hand.  I stepped onto the side deck and
    > walked to the bow, carrying the gps.  Sure enough the speed reading
    > increased to 6.4 knots while I walked and returned to 4 the moment I
    > stopped.  Oddly, while my first reaction was to laugh with delight,
    > my second was to throw the thing overboard.  Damned creepy, these
    > machines!
    > If nothing else, they sap a man's motivation to learn about running
    > fixes.
    > Best,
    > Patrick
    > --
    > Dr. Patrick Goold
    > Department of Philosophy
    > Virginia Wesleyan College
    > Norfolk, VA 23502
    > 757 455 3357
    > Charles Olson: "Love the World -- and stay inside it."
    | Richard B. Langley                            E-mail:
    lang@unb.ca         |
    | Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/
    | Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506
    453-5142   |
    | University of New Brunswick                   Fax:      +1 506
    453-4943   |
    | Fredericton, N.B., Canada  E3B
    5A3                                        |
    |        Fredericton?  Where's that?  See: http://
    www.fredericton.ca/       |

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