How could the robot localize after loading a saved map?

[daodao9801]

I am using the realsense D435i with the given example successfully.

ros2 launch nvblox_examples_bringup realsense_example.launch.py

After loading my saved map

ros2 service call /nvblox_node/load_map nvblox_msgs/srv/FilePath "{file_path: '/home/USERNAME/super_cool_map.nvblx'}"

The map can be seen together with "Esdf Slice" afterwards and everything looks fine. However, there seems no localization happening when the new map is loaded.

May I know how to let the robot find its position when a map is loaded? Is it automatically done or should I give it a "2D pose estimation" via RViz? Is it failed because the current depth map doesnt have enough feature?

Thanks advance for any suggestions.

[alexmillane]

nvblox, on its own, is just a mapping pipeline. Mapping being half of Simultaneous Localization and Mapping (SLAM).

In other words, nvblox on its own will not relocalize in a map. We expect another module to do that. You could configure, for example, isaac_ros_visual_slam, or another visual slam system, to do the relocalization.

[daodao9801]

Thanks. So ros2 action send_goal /visual_slam/save_map isaac_ros_visual_slam_interfaces/action/SaveMap "{map_url: /map} would be a more appropriate choice for saving a map which could be used for localizing later in the isaac_ros_visual_slam process?

[jaiveersinghNV]

Yes, that would be an appropriate usage of the save_map and load_map_and_localize actions in Isaac ROS Visual SLAM.