gpsd is a service daemon that monitors one or more GPSes attached to
a host computer through serial or USB ports, making all data on the
location, course, and velocity available to be queried on TCP port
2947 of the host computer.  With gpsd, multiple GPS client applications
(such as navigational and wardriving software) can share access to GPSes
without contention or loss of data.  Applications that presently use
gpsd include Viking, foxtrotgps and Kismet.

See README.build for some build options that might be useful.

To enable automatic startup of gpsd at boot time, or when a GPS device
is connected via USB, you need to do the following four steps:

1. Copy the file /lib/udev/rules.d/97-gpsd.rules to /etc/udev/rules.d/

2. Edit the file /etc/udev/rules.d/97-gpsd.rules and uncomment the line
(or lines) beginning '#ATTRS' that corresponds to your GPS hardware.
To avoid confusion with other USB serial devices that you might have,
do not uncomment lines that do not correspond to your GPS hardware.
But if you do not know which line to uncomment, and you do not have any
other serial devices, you can uncomment them all :-)

3. Make the file /etc/rc.d/rc.gpsd executable.
   chmod +x /etc/rc.d/rc.gpsd

4. Add the following lines to /etc/rc.d/rc.local
  if [ -x /etc/rc.d/rc.gpsd ]; then
    /etc/rc.d/rc.gpsd start
  fi

Configuration options may be set in the file /etc/rc.d/rc.gpsd.conf.
The defaults will usually be adequate.  However, if your GPS is on a
real (non-USB) serial port -- for example, /dev/ttyS0 -- you should add
/dev/ttyS0 to GPS_DEVICES in /etc/rc.d/rc.gpsd.conf.