Dylan Beaudette wrote:
On Thu, Apr 17, 2008 at 7:58 AM, Markus Neteler <[EMAIL PROTECTED]> wrote:
On Thu, Apr 17, 2008 at 12:05 PM, Peter Hopfgartner
<[EMAIL PROTECTED]> 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
Hi Dylan,
from the description on the web page it seems that Fresnel Zones are in
SPLAT, at least in recent versions.
I will have a look at it, tomorrow.
Thanks for your help,
Peter
R3 GIS
http://www.r3-gis.com
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