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 _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
