Load gnss_poser parameters from map_path directory

[VRichardJP]

The pointcloud_map.pcd file, the lanelet2_map.osm file, and the gnss_poser parameters are tightly coupled: all of them need to use the same coordinate system. Yet, there is currently no simple way to set the gnss_poser parameters.

The gnss_poser is started by the gnss.launch.xml file from the xxx_sensor_kit_launch package. In the sample_sensor_kit_launch package, only the coordinate_system parameter is set, and it cannot be modified from the outside. I don't think it makes much sense to set the coordinate system from the sensor kit launch files, since the coordinate system parameters are relative to the maps and not the vehicle.

Since the gnss_poser coordinate system parameters are relative to the maps, why not put them with the maps?

Precisely, couldn't we add a coordinate_system.param.yaml file next to the pointcloud_map.pcd and lanelet2_map.osm files? The coordinate_system.param.yaml would contains parameters such as:

• coordinate_system
• plane_zone
• latitude
• longitude
• altitude

The file would be passed from autoware.launch.xml down to the sensor kit gnss.launch.xml file, so that gnss_poser can load the configuration.

Obviously, such change would be breaking as everyone using a gnss sensor would have to create the coordinate_system.param.yaml file, but I think it would make the life easier for people using many maps.