[Olsr-dev] Including GPS information

Sven-Ola Tücke (spam-protected)
Sat Aug 2 10:09:11 CEST 2008


that is an easy task, since it's all build in the nameservice plugin and only 
needs to be configured. Here are two example snippets from olsrd.conf with 

<static positon example>
LoadPlugin "olsrd_nameservice.so.0.3"
        # the name to be flooded for my pc (note: no dots)
        PlParam "name"          "sven-ola-pcacer"
        # the file name for the hosts file (is written regulary and 
        # I don't want olsrd to overwrite /etc/hosts because I have
        # a lot of customized ip addrs written down there
        PlParam "hosts-file"    "/var/run/hosts"
        # as a security measure, each name in the hosts file
        # has a suffic - hence no "DNS spoofing" possible
        PlParam "suffix"        ".olsr"
        # elongate the interval for nameservice flooding msgs
        PlParam "interval"      "180"
        # elongate the time the flooded msgs are valid in the mesh
        PlParam "timeout"       "3600"
        # location of the socket file where received geopos can be grabbed
        # e.g. "cat /var/run/latlon.sh | /usr/local/bin/anyscriptyoulike.sh"
        PlParam "latlon-file"   "/var/run/latlon.js"
        # the gps position to flood into the mesh
        PlParam "lat"           "52.495332"
        PlParam "lon"           "13.454122"
</static position example>

<dynamic posistion example>
LoadPlugin "olsrd_nameservice.so.0.3"
        PlParam "name"          "sven-ola-gs"
        PlParam "hosts-file"    "/var/etc/hosts"
        PlParam "suffix"        ".olsr"
        PlParam "interval"      "180"
        PlParam "timeout"       "3600"
        # Instead of using a static position in olsrd.conf (which
        # requires restarting olsrd if you want to change that
        # this config param allows you to (regulary) write the
        # position in the configured text file - e.g. convince your
        # gps receiver softs to write current pos into that file
        PlParam "latlon-infile" "/var/run/latlon.txt"
        PlParam "latlon-file" "/var/run/latlon.js"
</dynamic position example>

The only drawback with the nameservice plugin: it uses flooding by default 
with relatively slow information spreading. Suitable for standard pedestrian 
mounted nodes I presume. For car/plane-based nodes you may need unicast (grab 
GPS via http or so)

While writing this, I investigated doppler shifts with wifi channels. Is wlan 
ok to handle 100km/h delta-V? Well, the speed diff between (spam-protected) 
and (spam-protected) should be *calccalccalc*:

2.412 GHz / 2.417 GHz * 1.08 Tmh - 1.08 Tmh == 0.0022 Tmh

OK - should be fine. 0.002 Terameters/hours is fast enough. To make sure I've 
googled a bit and found this:


But there should be protocol probs because a 150 Kmh car is very fast out of 
reach <ggg> 

// Sven-Ola

Am Freitag 01 August 2008 23:39:55 schrieb Resul Cetin:
> Hello People,
> I want to include GPS Information to OLSR. Im thinking to check the GPS
> Koordinates before Flooding and send the Flooding maybe to nodes, which is
> closer to the sending node. Im planning to read the GPS Koordinates serial
> with a GPS receiver.
> I read in a previous messages, that sven ola already programed a file
> "/var/run/latlon.txt." where you can type the Koordinates.
> But I couldnt find it. Could somebody tell me where I can find this file.
> greetings,
> elturco

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