Refactor navsat_gpxfix demo (#642)

* Refactor navsat_gpxfix demo

Signed-off-by: Carlos Agüero <[email protected]>

ros_gz_sim_demos/README.md

@@ -134,7 +134,12 @@ Publishes magnetic field readings.
 
 Publishes satellite navigation readings, only available in Fortress on.
 
+GNSS information can be obtained as:
+
+    # sensor_msgs/msg/NavSatFix
     ros2 launch ros_gz_sim_demos navsat.launch.xml
+    # gps_msgs/msg/GPSFix
+    ros2 launch ros_gz_sim_demos navsat_gpsfix.launch.xml
 
 ![](images/navsat_demo.png)
 

ros_gz_sim_demos/config/navsat_gpsfix.yaml

@@ -0,0 +1,6 @@
+# Navsat_gpsfix configuration.
+- topic_name: "/navsat"
+  ros_type_name: "gps_msgs/msg/GPSFix"
+  gz_type_name: "gz.msgs.NavSat"
+  lazy: true
+  direction: GZ_TO_ROS

ros_gz_sim_demos/launch/navsat_gpsfix.launch.xml

@@ -0,0 +1,12 @@
+<launch>
+  <gz_server
+    world_sdf_file="spherical_coordinates.sdf"
+    use_composition="True"
+    create_own_container="True" />
+  <ros_gz_bridge
+    bridge_name="ros_gz_bridge"
+    config_file="$(find-pkg-share ros_gz_sim_demos)/config/navsat_gpsfix.yaml"
+    use_composition="True" />
+  <node pkg="rqt_topic" exec="rqt_topic" args="-t" />
+  <executable cmd="gz sim -g" />
+</launch>