[GRASS-user] LOS, Fresnel Zones, Multi-Line wave propagtion and GHz communications

[Dylan Beaudette]

On Thu, Apr 17, 2008 at 7:58 AM, Markus Neteler <neteler at osgeo.org> wrote:
> On Thu, Apr 17, 2008 at 12:05 PM, Peter Hopfgartner
>  <peter.hopfgartner at r3-gis.com> wrote:
>  > Dear GRASS community,
>  >
>  >  I would like to simulate the strength of a signal emitted from an antenna
>  > and received by a receiver.
>  >
>  >  As a first approach r.los gives a good start. Anyway, more accurate results
>  > could be  obtained by  taking obstruction in the first Fresnel Zone into
>  > account. Finally, having a way to calculate the impact on indirect
>  > paths/reflections, should lead to a reasonably accurate signal strength map.
>  >
>  >  Did anybody work on some of these issues, possibly in combination with
>  > GRASS? Is there a good starting point for the calculation of the obstruction
>  > within the first Fresnel Zone. And the reflections?
>
>  Hi Peter,
>
>  reading
>   http://en.wikipedia.org/wiki/Fresnel_zone
>  I remembered
>   Mapping Wi-Fi Network Range with GRASS, Kismet, and python
>   http://casoilresource.lawr.ucdavis.edu/drupal/node/470
>
>  Could this be helpful?

Maybe only as an idea of how complicated radio propagation can be. The
referenced page on Wifi / GRASS doesn't really do any important math
or modeling-- rather it was more a test case on interpolating signal
strength measurements.

I am sure that Brad Douglas has some good insight into radio wave
propagation modeling.

There is also an open source application called 'splat' :
http://www.qsl.net/kd2bd/splat.html

I do not know if splat can account for near-surface conditions (i.e.
Fresnel Zone) or higher elevation atmospheric parameters (ionosphere).

It would be nice to have a couple of more robust LOS-like modules in
GRASS for this type of work.

Cheers,

Dylan