On Mon, 15 Jul 2002, Alan B. Pearce wrote:

>>So the general idea is
>>1) they need an unrestricted view of the sky
>>2) you have to leave them for a while to get a fix on
>>the satellites- 5mins? 10 mins? longer?
>
>Well these two factors are common to any and all GPS units. Typically thay
>will not work inside a building because the building materials have too high
>an absorption at the 1.5something GHz they use, and it takes a while for the
>receiver correlator to lock onto enough satellites in view to obtain an
>accurate position fix.

The funny part being that they won't work even inside the attic of a wood
thatched house, even less in a tile hatched one. I don't know if it's the
nails, or the humidity and treatment chemicals in the wood. Trees stop it
pretty well (ONE tree should be enough). Of course I think that the
military have means to get better signal. I don't think that they need to
poke a hand out of a trench under fire to get a fix ;-).

Peter

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