[time-nuts] gravity controlled pendulumn clock?

bg at lysator.liu.se bg at lysator.liu.se
Mon Dec 12 18:46:12 EST 2011

> Folks,
>      Actually, the USGS goes around measuring the local gravitational
> constant in various places.  There was a gravimeter set up in the
> basement of one of the local universities a few years back doing just
> that.  And some time ago, the U.S. spent a fair amount of time, money
> and effort (presumably as did the Soviet Union and others) mapping
> the Earth's external gravitational field to correct for its effect on
> ballistic missile trajectory.  Probably still do.
>              Francis

Your intertial naviation systems accelerometers will always sense gravity.
The INS computations will need to substract the local gravity vector
before integrating acceleration to velocity and then position. This
becomes very critical for high accuracy applications where GPS is either
not available (submarines) or ICBMs which should work even with GPS
knocked down.

This is a reason to map gravity anomalies.



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