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

Peter Hopfgartner peter.hopfgartner at r3-gis.com
Thu Apr 17 11:36:18 EDT 2008

Dylan Beaudette wrote:
> 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
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,


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