GPS reference point

[Annika-wyt]

Summary

reference_gps_frame.py

• publish a static transform between UTM and the reference GPS latitude and longitude, which is the (utm -> reference_gps) transform in the tf tree. Also publishes a topic /gps/reference_point
• The added requirement pyproj is for this script
• To run the script

<node name="reference_gps_frame" pkg="svea_sensors" type="reference_gps_frame.py" output="screen">
  <rosparam subst_value="true">
	  reference_gps: [59.350791, 18.067825]
  </rosparam>
</node>

• the reference_gps input can be changed. The format is [latitude, longitude]

---

latlong_to_xy.py

• A supplementary node which calculate the current state with reference to the reference GPS.
• It takes in the gps/filtered from the navsat node, then calculate the distance and angle between the gps/filtered and the gps/reference_point. The script publishes a topic gps/reference_state and publishes transform (reference_gps -> base_link_fixed_gps)
• The graph on the left plots the topic gps/reference_state for 2 runs, and for comparison, the graph on the right shows the result from gps/filtered from the 2 runs

• To run the script

<node name="latlong_to_xy" pkg="svea_sensors" type="latlong_to_xy.py" output="screen"/>