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    Re: Interesting challenge
    From: Antoine Couëtte
    Date: 2012 Aug 6, 20:32 -0700

    To Andrew Nikitin,

    Dear Andrew,


    So ... you too have devised on your own a way to get a reliable CelNav fix without any preliminary knowledge of some DR position ...

    WELCOME TO THE CLUB, ANDREW THEN ... altogether with Andrés, Peter and (probably) a few others

    Kermit


    ******************************

    Lu,

    Solution to this problem does not require knowledge of spherical trigonomtry,
    just some linear algebra and the ability to convert between rectangular and
    spherical coordinates.

    You need to find point of intersection of 3 circles on a sphere.
    You know the centers of circles (defined by GP of bodies, or coordinates of the cities in your case) and the distance along the surface fromthe center to the edge of the circle. If you notice that each circle lies on a plane, which is perpendicular to the radius-vector connecting center of the sphere and GP, the point of intersection of the circles is the point of intersection of the planes.
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