In uk.transport.london message ,
Wed, 13 Feb 2008 00:21:44, John Rowland
n.co.uk posted:
and if all the satellites were exactly in a plane, there
would be no information to calculate the height.

Not so. Consider two satellites at the same height above a flat earth,
for high and low satellites, and emitting pulses simultaneously.


S1 S2









s1 s2
_____JR______________ - You X -


The delay between hearing S1 & S2 is clearly less than that between
hearing s1 & s2. JR can therefore tell, if the X-positions of the
satellites are known, how far below the satellite line he is.

--
(c) John Stockton, nr London UK.
Web URL:http://www.merlyn.demon.co.uk/ - FAQish topics, acronyms, & links.
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