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    Re: Dip-meter again
    From: Lu Abel
    Date: 2012 Apr 11, 13:54 -0700
    If you read the history of GPS, soon after Sputnik's launch American scientists figured one could get positional data (maybe only a line-of-position, not a fix) from the Doppler shift in a satellite's signals.   This resulted in a very hush-hush project that resulted in the Transit system.   Multiple US defense projects then looked for a next-generation follow-up.   Fortunately (at least for the modern world) the projects were merged with the best ideas from each being selected as the projects consolidated and moved forward.   One specific I remember is that one of the projects proposed that the receivers contain an atomic clock!   For 1960s or early 1970s technology, not unreasonable -- we had not seen the dramatic effects of shrinking semiconductor technology.   Fortunately, that got changed.   There's a wonderful picture of a soldier wearing a full backpack with a large antenna sticking out of it.   It's a single-channel GPS receiver!   (wish I could find a copy to attach, but I can't)


    From: Alexandre E Eremenko <eremenko@math.purdue.edu>
    To: NavList@fer3.com
    Sent: Tuesday, April 10, 2012 11:14 AM
    Subject: [NavList] Re: Dip-meter again


    Richard,
    Thanks.
    Do you know how accurate it was?

    > The first TRANSIT satellite was launched in 1961. The system was
    > declared operational in 1964 and became classified. In 1967 it was
    > declassified and became available for civilian use.

    Alex.






       
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