This would be the procedure to install and compile
the gps-umd package locally, but you can bypass
it and install the ROS integrated version.
Anyway, a few common things have to be done. See below:
=========== LOCAL WAY ===================
Stack gps_utm downloaded with
	git clone git://ram.umd.edu/ros/gps_umd.git
As can be seen in rosdep.yaml, the following 
package has to be installed:
	sudo apt-get install libgps-dev
Then simply perform a rosmake
=========== END OF LOCAL WAY ===================

====GLOBAL WAY ===============

sudo apt-get install ros-<distro>-gps-umd

You can also install simple nmea drivers that do not
require the gpsd to be running:
	sudo apt-get install ros-<distro>-gps-drivers
*Actually this did not work. Save your time....*

=== COMMON CONCERNS =================

The gpsd_client (from gps-umd) obtains data after gpsd 
deamon in the operating system: if not installed/running
install it with:
	sudo apt-get install gpsd
Then configure it:
	dpkg-reconfigure gpsd
to change the options into something like:
	START_DAEMON="true"
	GPSD_OPTIONS=""
	DEVICES=""
	USBAUTO="false"   # "true" to make autodetection of USB port!
	GPSD_SOCKET="/var/run/gpsd.sock"
If you do not want the gpsd scramble your serial ports,
then do not allow auto USB detection and impose your
serial port manually, e.g.
	gpsd /dev/ttyUSB0
But if you feel it's OK, use the automatic detection
by the system. use: USBAUTO="true"
(risk - conflict with other USB devices already
on the system)

You can test if GPS is operational by running
several tools such as xgps... you should see
a map of satelites... :-)

The gps_umd ROS stack includes two packages:
	gpsd_client
		includes the gpsd_client node and some other unused node
	gps_common 
		includes the utm_odometry_node node 

In some GPS receivers there is a problem with GPS time so
the command must be invoked setting the gps_time as false.
The actual command is something like this:
	rosrun gpsd_client gpsd_client _host:=localhost _port:=2947 _use_gps_time:=false
Port is the default. May be changed.

So a launch file has been created to easily launch this gpsd_client

V. Santos, 14-Mai-2013