Re: gps

On Jun 26, 10:58 am, "John Campbell" <spaml...@[EMAIL PROTECTED]
> wrote:
> "STUARTe" <jabluvs...@[EMAIL PROTECTED]
> wrote in message
>
> news:1182860948.881504.125610@[EMAIL PROTECTED]
>
> > if you know the time/date and the frequency of the broadcast signal
> > from a gps satellite, could you determine your position by using the
> > doppler ****ft of the recieved signal?
>
> > you also have a fix on north.
>
> > it might be acceptable to approximate the earths surface under the
> > satellite as a flat plane?
>
> write out the equations
>
> There is a system that uses two equatorial sats and alitude map. (not
gps)

aren't GPS satellites geosynchronous, geo stationary?
ones going parallel over the equator would only reveal lattitude,
but if they are evenly spaced you get no longitude info

if you have some that operate on a polar tilt orbit,
they are just going to appear to move north & south over a given range

unless the north south oscillation/range is identifiably different for
individual satellites
that wouldn't really give you any clues other than your span between
them
or if they had eccentric individual timing relation****ps
ie. satellite a & b had north south timings closer in synchronicity
than either with c
or their position in relation****p to equatorial satellites wasn't
perfectly equidistant,
you might calculate something from that.

the only dopler effect would be the north south oscillations.
even if you are in motion on the ground i don't think the dopler
effect will give any additional info
only oddities of satellite relation****ps would give you any clues
where you were

the weakness of signal [distance dependent] might give you one of a
couple of potential positions on the earth
divided into however many intervals created by satellites there were
over the planet.

It is all very dependent on detailed information about the satellite
orbits before hand.