Hardware Reference
In-Depth Information
The gpsd package provides an interface daemon for GPS receivers, so that regular
applications that want to work with GPS data don't have to know the details of how
to talk to your particular brand of GPS. So gpsd will be running in the background
and relaying messages between your GPS and other applications through the 2947
TCP port.
Let's start gpsd using the following command:
pi@raspberrypi ~ $ sudo gpsd -n /dev/tty[XXXX]
Now we can try reading data from gpsd by using the basic GPS console client:
pi@raspberrypi ~ $ cgps -s
cgps displaying GPS data obtained from seven satellites
You'll want to position your GPS receiver so that it has a clear view of the sky. If
your Status continues to display NO FIX , try placing your GPS on a windowsill.
The left-hand side frame contains the information that has been obtained from the
list of satellites in the right-hand side frame. To quickly verify the coordinates on
a map, simply paste the Latitude and Longitude strings into the search field at
http://maps.google.com .
Press the S key to toggle the raw NMEA sentences that we've hidden by supplying
the -s argument to cgps , or press the Q key to quit.
Tracking the GPS position on Google Earth
So what can we do with this GPS data? We can either log the Pi's position at regular
intervals to a waypoint database that can then be plotted onto a map, or we can
update the position in real time on a remotely connected Google Earth session for
that classic spy movie beaconing look.
 
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