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Gary LaPook wrote:
I don't know but I'm pretty happy with the performance of my Brunton
pocket transit, and the're only a couple hundred bucks new and less on
E-bay.

gl

George Huxtable wrote:

>Relating to Geoffrey Kolbe's suggestion that a laser "gyro" would make a
>suitable handheld compass-
>
>Nicolas de Hilster confirms my presumption that such systems remain
>furiously complex and expensive.
>
>But there's a more fundamental objection to their use as a simple handheld
>compass, as I see it (on second thoughts).
>
>What such instruments measure is the changes in orientation of three axes,
>in absolute space. What a handheld compass is expected to provide is a
>direction, toward true North, along the Earth's surface. But the plane of
>the Earth's surface, at the position of the navigator, is changing, all the
>time, for two reasons; because of the rotation of the Earth, and because of
>the motion of the observer with respect to the surface of the Earth. So, any
>such laser "gyro" would need to have some sort of knowledge of these
>quantities. In a similar way, a ship's gyroscopic compass needs to have some
>sensor of the local horizontal, and have correction factors applied which
>allow for the vessel's motion.
>
>I imagine that in the case of a laser "gyro", this information would be
>provided by an interface with some form of GPS receiver, with a sensor of
>the direction of gravity. But it takes us a long way from the simple
>hand-held device of Geoffrey's concept. How does he propose it will work, in
>more detail?
>
>George.
>
>contact George Huxtable at george@huxtable.u-net.com
>or at +44 1865 820222 (from UK, 01865 820222)
>or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
>
>
>>
>
>
>


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