Satellite Range

I know this isn't directly linked with DSP, but it is telecommunications,
and someone should know the answer to this!

Assume a ground-station has a longitude of 5.17degW and a latitude of
50.05degN
There is an Atlantic Ocean Satellite with longitude 30.00degW.

How can I calculate the range of the satellite from the earth station?

I have had a look at some literature, but nothing seems to be what I need.
What equations do I need?

Phil

Are you just trying to find the distance between the two points?  Knowing
the radius of the earth and the geosych orbit, you can find 3D polar coords
of the two points, using the center of the earth as the origin of the polar
coord system.  Then you can convert those polar coords to cartesian coords.
This is pretty easy and you can find the conversions in a calculus book.
Then you have two cartesian vectors; subtract one from the other and find
the magnitude of the result.
-Kevin

"Philip Newman" <nojunkmail@ntlworld.com> wrote in message
news:atRjc.79$RI.28@newsfe1-win...
> I know this isn't directly linked with DSP, but it is telecommunications,
> and someone should know the answer to this!
>
> Assume a ground-station has a longitude of 5.17degW and a latitude of
> 50.05degN
> There is an Atlantic Ocean Satellite with longitude 30.00degW.
>
> How can I calculate the range of the satellite from the earth station?
>
> I have had a look at some literature, but nothing seems to be what I need.
> What equations do I need?
>
> Phil
>
>

"Kevin Neilson" <kevin_neilson@removethiscomcast.net> wrote in message
news:jCRjc.6205$RE1.758298@attbi_s54...
> Are you just trying to find the distance between the two points?  Knowing
> the radius of the earth and the geosych orbit, you can find 3D polar
coords
> of the two points, using the center of the earth as the origin of the
polar
> coord system.  Then you can convert those polar coords to cartesian
coords.


> This is pretty easy

go on then!


> and you can find the conversions in a calculus book.
> Then you have two cartesian vectors; subtract one from the other and find
> the magnitude of the result.
> -Kevin

thanks

Phil




>
> "Philip Newman" <nojunkmail@ntlworld.com> wrote in message
> news:atRjc.79$RI.28@newsfe1-win...
> > I know this isn't directly linked with DSP, but it is
telecommunications,
> > and someone should know the answer to this!
> >
> > Assume a ground-station has a longitude of 5.17degW and a latitude of
> > 50.05degN
> > There is an Atlantic Ocean Satellite with longitude 30.00degW.
> >
> > How can I calculate the range of the satellite from the earth station?
> >
> > I have had a look at some literature, but nothing seems to be what I
need.
> > What equations do I need?
> >
> > Phil
> >
> >
>
>

Philip,
Why not just call Goonhilly and ask them? Or do you have to show your
workings in your homework answer? ;-)
Cheers, Syms.

"Symon" <symon_brewer@hotmail.com> wrote in message
news:c6op0i$dqv33$1@ID-212844.news.uni-berlin.de...
> Philip,
> Why not just call Goonhilly and ask them? Or do you have to show your
> workings in your homework answer? ;-)
> Cheers, Syms.
>
>
Someone knows their Satellites!

I do believe I get extra marks for showing workings!

I think I got it, not sure though.

Thanks

Phil

"Philip Newman" <nojunkmail@ntlworld.com> writes:

> I know this isn't directly linked with DSP, but it is telecommunications,
> and someone should know the answer to this!
> 
> Assume a ground-station has a longitude of 5.17degW and a latitude of
> 50.05degN
> There is an Atlantic Ocean Satellite with longitude 30.00degW.
> 
> How can I calculate the range of the satellite from the earth station?
> 
> I have had a look at some literature, but nothing seems to be what I need.
> What equations do I need?

There's not enough information here to compute this geometrically, is there?
I'm not up on these coordinate systems, but is it not true that "longitude
30.00 degrees West" only specifies the longitude of the satellite and not
the altitude? Thus the range cannot be computed. 

Perhaps they want you to be a little creative with a respone like "ping it
and look for the time of return?" 
-- 
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
randy.yates@sonyericsson.com, 919-472-1124

"Randy Yates" <randy.yates@sonyericsson.com> wrote in message
news:xxphdv4t0gj.fsf@usrts005.corpusers.net...
> "Philip Newman" <nojunkmail@ntlworld.com> writes:
>
> > I know this isn't directly linked with DSP, but it is
telecommunications,
> > and someone should know the answer to this!
> >
> > Assume a ground-station has a longitude of 5.17degW and a latitude of
> > 50.05degN
> > There is an Atlantic Ocean Satellite with longitude 30.00degW.
> >
> > How can I calculate the range of the satellite from the earth station?
> >
> > I have had a look at some literature, but nothing seems to be what I
need.
> > What equations do I need?
>
> There's not enough information here to compute this geometrically, is
there?
> I'm not up on these coordinate systems, but is it not true that "longitude
> 30.00 degrees West" only specifies the longitude of the satellite and not
> the altitude? Thus the range cannot be computed.
>
> Perhaps they want you to be a little creative with a respone like "ping it
> and look for the time of return?"
> -- 
> Randy Yates
> Sony Ericsson Mobile Communications
> Research Triangle Park, NC, USA
> randy.yates@sonyericsson.com, 919-472-1124

I assume that the latitude of the satellite is zero - that is it is in line
with the earths equator, and the point of origin is the earth's centre.

Phil

"Randy Yates" <randy.yates@sonyericsson.com> wrote in message
news:xxphdv4t0gj.fsf@usrts005.corpusers.net...
> "Philip Newman" <nojunkmail@ntlworld.com> writes:
>
> > I know this isn't directly linked with DSP, but it is
telecommunications,
> > and someone should know the answer to this!
> >
> > Assume a ground-station has a longitude of 5.17degW and a latitude of
> > 50.05degN
> > There is an Atlantic Ocean Satellite with longitude 30.00degW.
> >
> > How can I calculate the range of the satellite from the earth station?
> >
> > I have had a look at some literature, but nothing seems to be what I
need.
> > What equations do I need?
>
> There's not enough information here to compute this geometrically, is
there?
> I'm not up on these coordinate systems, but is it not true that "longitude
> 30.00 degrees West" only specifies the longitude of the satellite and not
> the altitude? Thus the range cannot be computed.
>
> Perhaps they want you to be a little creative with a respone like "ping it
> and look for the time of return?"
> -- 
> Randy Yates
> Sony Ericsson Mobile Communications
> Research Triangle Park, NC, USA
> randy.yates@sonyericsson.com, 919-472-1124

I assumed if the longitude was given without the latitude, this implies it's
geosynchronous and then the latitude and altitude are known.  It is a big
assumption, though.
-Kevin

"Randy Yates" <randy.yates@sonyericsson.com> wrote in message > Perhaps they
want you to be a little creative with a respone like "ping it
> and look for the time of return?"

Sounds like it could be a job for a Barometer....

Cheers, Syms.

Philip Newman wrote:
> I know this isn't directly linked with DSP, but it is telecommunications,
> and someone should know the answer to this!
> 
> Assume a ground-station has a longitude of 5.17degW and a latitude of
> 50.05degN
> There is an Atlantic Ocean Satellite with longitude 30.00degW.
> 
> How can I calculate the range of the satellite from the earth station?
> 
> I have had a look at some literature, but nothing seems to be what I need.
> What equations do I need?
> 
> Phil
> 
> 

Assuming the satellite is in geostationary orbit at 0 deg latitude and 
35786 km altitude, the azimuth, elevation and range are give below:

Azimuth(deg)	Elevation(deg)	Range(m)
148.8678406	27.99588761	38784989.47

These results come from the freely-available ArrayTran software application.

OUP