gnss

GNSS stack for ROS

Tools for working with Global Navigation Satellite Systems.

Usage

The node enu_to_pose in nodes/enu_to_pose.py needs a network connection to a rtklib instance. rtklib is built in this package with the Makefile (use rosmake). rtklib then should supply the solution output on the network connection configured in the enu_to_pose-node. Examples for rtklib with solution output on the default network port and input of data from another stream are included as examples.

The launch file rtklib.launch starts an rtklib instance as well as the enu_to_pose-node. For testing purposes it is helpful to start rtklib manually with the rtknavi-GUI or manually with the simple shell wrapper script start_rtklib.sh.

Example step-by-step instructions:

• Add package to your ROS workspace with rosinstall
• Build rtklib with rosmake
• Supply a pre-recorded skytraq measurements file to the port specified in enu_single.conf, e.g. cat <skytraq_measurements_file> | nc -l -p 10000
• Start rtklib and enu_to_pose-node with roslaunch rtklib.launch
• Now, the rostopic /enu should show ENU pose informations. If the quality of the provided GNSS signal is sufficient, coordinate transforms are published to the ROS system

Advanced example procedure for debugging including intermediate testing steps:

• Provide GNSS measurements (see above)
• Start rtklib with ./start_rtklib.sh enu_single.conf using these measurements
• Test rtklib solution by connecting to the output port manually and checking the solution for a valid position nc localhost 3333
• Ensure a roscore process is running: Call roscore
• Start the node with rosrun rtklib enu_to_pose.py

Example output

rtklib processes the GNSS measurements into position solutions in the ENU coordinate system and provides these informations along with quality information and other data on an output port, if configured, as can be seen in the example configuration files. Each line should look like the following example:

2012/08/23 12:49:30.402    863028.7989   4720911.2174  -2194093.2995   5   9 3.0176   5.8136   3.4867   2.6834   3.1125   1.7950   0.00    0.0

The enu_to_pose node provides coordinate transforms and prints log messages to the console. The position from rtklib is provided in the rostopic /enu and looks like this:

header:
  seq: 565
  stamp:
    secs: 1376397269
    nsecs: 369039058
  frame_id: /map
pose:
  position:
    x: 863027.3836
    y: 4720911.2261
    z: -2194086.6277
  orientation:
    x: 0.0
    y: 0.0
    z: 0.0
    w: 0.0