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Global Packages

The global layer gives the robot memory and direction beyond sensor range: a persistent 3D map of everywhere it has been, and a global planner that reasons over that map to produce a coarse waypoint path. Its output — global_plan — is the handoff to the local layer, which refines it into collision-free trajectory segments. Because global planning is not flight-critical, it is the one part of the stack that may run off-vehicle: the lite_offload_global split stack moves it to a ground host.

Sub-layers

  • World Model — the persistent VDB voxel map built from filtered sensor clouds
  • Planning — global planners (reference implementation: random walk exploration)

Launch

The global layer is composed by the selected stack's entry launch file (stacks/<name>/launch/*.launch.xml): the trunk stacks include vdb_mapping_ros2.py and random_walk_planner.launch.xml directly — see stacks/full_default/launch/stack.launch.xml. The global_bringup package (robot/ros_ws/src/global/global_bringup) owns the cross-package VDB config (config/vdb_params.yaml), which the stack entry file passes to the mapper.

Key Interchanges

  • global_map (§3) — the VDB map topics the global planner consumes
  • global_plan (§4) — the waypoint path handed to the local planner; the one interchange that may cross a machine boundary in split stacks

See Also