On Jun 29, 8:04 pm, STUARTe <jabluvs...@[EMAIL PROTECTED]
> wrote:
> On Jun 29, 3:31 pm, gclgour...@[EMAIL PROTECTED]
wrote:
>
>
>
> > On Jun 28, 9:16 pm, STUARTe <jabluvs...@[EMAIL PROTECTED]
> wrote:
>
> > > On Jun 28, 3:01 pm, gclgour...@[EMAIL PROTECTED]
wrote:
>
> > > > On Jun 28, 10:33 am, Gene Wagenbreth <genewxxx@[EMAIL PROTECTED]
> wrote:
>
> > > > > GPS satellites are not geosynchronous
>
> > > > You have to be able to identify individual satellites & have pre-
> > > > information about their orbits.
> > > > I will guess identity is done through frequencies, so dopler
variance
> > > > wouldn't help with that.
> > > > Unique identifiable characteristics of orbits or orbit
relation****ps
> > > > could work,
> > > > again dependent on pre-information about which satellites did
what.
>
> > > > If you can identify dopler variance, how would you do that without
> > > > getting a frequency reading?
> > > > Only something very odd like a receiver that only identified
frequency
> > > > differentials withoug identifying the actual frequency would
apply, i
> > > > think.
> > > > or maybe you are you thinking of using reflective radar on the
> > > > satellites?
> > > > As if their transmission capabilities have shut down?
> > > > I am not sure if that would exceed radar distance capabilities.
> > > > ie. the reflection wave might be too weak.
>
> > > dog days of summer?
> > > anyway. if i know the sattelite is at altitude 600 miles directly
over
> > > the wa****ngton monument and is moving southwest at 17,222 mph and
the
> > > dopler ****ft is that of 100 Hz above 1 mega Hertz, can i calculate
my
> > > position on earth?
> > > and don't say it's the basement of the alamo.
>
> > this may be totally incorrect
> > I will for simplicity at this point treat it as if the satellite is
> > traveling on the ground
>
> > 17222 mph = 4.78388 mps
> > it is broadcasting 1,000,000 waves per sec at the speed of light,
> > 186,000 mps
> > so 1,000,000 waves are spread over 186,000 miles
> > 1000000/186000 = 5.376 waves per mile per sec
> > so to get 100 waves [100hz] you have to get
> > 100/5.376 = 18.6 miles per second towards you
> > since the satellite is only traveling at 4.7839 mps this is impossible
> > unless you are moving towards it.
>
> > you will have to crank that satellite speed up or reduce the hz
> > variance.- Hide quoted text -
>
> > - Show quoted text -
>
> i confess to being lazy. if i say the Doppler ****ft is 10 hz will that
> give us a clear description of the problem with no further obstacle to
> arriving at a solution?
> also, i now propose using time of arrival as well as doppler ****ft to
> determine position.
i am totally out of my depth,
but it is engaging to attempt it
The satellite is broadcasting a sphere of waves every second with a
radius of 186000 miles
the ratio of 600 mile over 186000 is 0.0032 so i will just treat this
as working on a flat plane of broadcast
Say the satellite is traveling at 60,000 mph
that is 60000/3600 [sec/hr] = 16.67 mps
1000000 hz is spread over 186000 mile
so 1000000/186000 is again 5.376 waves per mile per sec
10 hz differential is 10/5.376 = 1.86 miles
so the satellite is moving at 16.67 miles [in a sec]
and from our angle to that line we only see 1.86 of it
so we sit at a 1.86 mile base right triangle with a hypotenuse of
16.67
we need to find the satellite's angle of travel to us
so arccos(1.86/16.67) = 83.6 degrees
if we were directly in the path of the satellite we would expect to
get 16.67 miles or 16.67 * 5.376 = 89.61792 hz increase differential
if we were directly behind the satellite we would lose 89.6 hz
perpendicular to the satellite's path we would see exactly 1mhz
frequency
so we are on a vector from the wa****ngton monument not quite
perpendicular [90 degrees] from the path of the satellite, but a
vector from the monument slightly ahead of that, or 83.6 degrees
SW + 83.6 degrees
I think to know our distance from the monument we have to know the
rate of differential change
the faster that change the closer we are, slower = further
or perhaps signal weakness or strength [amplitude] would also work if
we knew the originating signal strength
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