Radio Propagation Modelling, from a GIS view point

Question

I've had a request from another department involved in telecommunications to revamp elevation data into GTOPO30, DTED or SRTM formats as input into a program called Radio Mobile. They are working on adding infill sites to low signal areas. Radio Mobile looks to be a program with history and a quick peruse of the message archives and tutorial sites shows there is active user community.

The reliance on somewhat dated elevation formats, e.g. they don't seem to have heard of geotiff and do everything in geographic lat/long, got me wondering about the overlap between GIS and radio signal analysis. What communities and/or software systems are there out there approach Radio Propagation Modelling from a GIS point of view? What's your assessment of their GIS "savvyness"?

EDIT: This could also be phrased as, where does someone who knows a something about GIS but nothing about radio signal propagation go to learn more?

Answer 1

I have encountered this while working on broadband communications and mobile telephony for the FCC (in the US). For an introduction to this viewpoint, see Wagen & Risk, Radiowave propagation, building databases, and GIS: anything in common? A radio engineer's viewpoint.

The stuff I have seen ranges from calculations that are so simple they're stupid (create buffers, or use viewshed calculations) to ones that model electromagnetic propagation through the atmosphere around a cluttered environment (hills, trees, buildings, etc.). The sophistication is there, but not all telcos have the knowledge, resources, or even the need to use it.

Answer 2

From NOAA

I think frequency and the condition of the ionosphere will be factors. Signals can bounce off the ionosphere, reducing the impact of terrain. Several years back I looked into interfacing VOACAP with GIS. I see now there is an online version. In higher latitudes, as I recall, the ionosphere is not very predictable.

Update:

Also, the Review of HF propagation analysis & prediction programs looks at 54 different application. Notice how each of them seems to have a global map associated with them. From a GIS point of view, if you are siting a HF transmitter, you'd like to know statistically how well you will be received by your target audience, which is how the Voice of America used VOACAP. All the source code I've seen is FORTRAN from the cold war era.

GIS can be used to evaluate alternative transmitter sites This can be done by generating time of day maps (say, every hour) showing signal strength distribution for each proposed site. This video shows time of day maps. Combine the time of day maps to create a map showing number of hours of where your reception is sufficent for a site. Some areas may only be able to hear you 2 hours a day while other areas 6, and so on. You can then overlay that map with population to determine number of potential listener hours for a site.

Answer 3

Maybe you want to the also "The Radio Planning Tool for GRASS GIS" - Raplat. Citation: "It is especially designed for radio coverage calculation of GSM/UMTS systems, but can be applied also to other wireless systems in the frequency range 400 MHz – 2.4 GHz (e.g. TETRA, WiFi). Its structure is modular and characterized by high level of flexibility and adaptability."

See http://grass.osgeo.org/wiki/Addons#Raplat

Answer 4

This answer is a little bit off-base but it might help someone.... I tried to tackle this problem a few weeks ago (trying to get cell coverage data), but the questions I kept asking is why?

I found a quicker solution by using the interactive maps that are already provided by cell providers. http://www.thadwester.com/1/post/2011/11/custom-cell-coverage-map-the-easy-way.html

Now, I know you want to plan, so you will need custom analysis, but the basemap will still be useful to plug into.

Interesting solution with radio mobile. Going to give it a go.

Answer 5

I have been working on using RM to map out the current range of >30 towers in my work area (about 64,000km2) so that in a disaster inhabitants of remote properties can have a clear understanding of what communication pathways are available to them in areas which they can access at that time.

A major part of this process was converting the txt file created by the Cartesian Coordinate plot system of RM to a vector polygon shapefile and dealing with the large datasets (over 1 GB text files per tower and 30million lines) that were created. I am happy to share all the models and python scripts that we created for this, if any of you would like (simply email me a request).

I have attached a summary document of the process used and would really appreciate any feedback from the RM user group - I am a spatial and ecological scientist and so have had to rely heavily on advise from Ian D Brown (G3TVU) for the communication engineering aspects of the work.

Please see/edit/comment on https://docs.google.com/document/d/1WW9IKQWlrhc0-VBJqM79dNx3e4p6Xs89QlqV9wAoi6Q/edit

Cheers,

George Corea GIS Specialist Atherton, QLD, Australia

Answer 6

You may want to check out SPLAT and ITM