as2_state_estimator

State estimation server for Aerostack2.

The state_estimator node maintains the drone’s pose and velocity, publishes them on self_localization/*, and broadcasts the REP-105 transform chain earth -> map -> odom -> base_link. It does not itself know how to estimate anything: the actual estimation is done by plugins loaded at runtime through pluginlib.

The node owns the output path. Plugins never touch /tf or the publishers directly, they report state updates through an interface and the node decides what gets published.

graph LR
  S[sensor topics] --> P[Plugin]
  P -->|report| W[PluginWrapper]
  W --> A[authority check]
  A --> C[StateEstimator]
  C --> T["/tf, /tf_static"]
  C --> L["self_localization/pose<br/>self_localization/twist"]

Index

• Plugins
• Frames
• Interface
• Parameters
• Launching
• Writing a plugin
• Testing

Plugins

The plugin is selected with the plugin_name parameter. It accepts either a single string or a list of strings, so more than one plugin can be loaded in the same node.

Multi-plugin is expressible but not yet arbitrated. Both plugins currently claim every transform type, so loading two of them is last-write-wins rather than a real handover. Per-plugin scoping is future work.

Frames

The node follows REP-105:

earth is shared by every drone. map, odom and base_link are namespaced per drone (drone0/map, drone0/odom, …).

Empty frame names resolve to the namespace. Setting base_frame_id: "" in a node under namespace drone0 gives the frame drone0 instead of drone0/base_link. This is what Gazebo needs, since it roots each model’s TF at the bare model name, and it replaces the old use_gazebo_tf parameter.

Plugins read TF through a filtered listener that hides the estimator’s own three transforms, so a plugin cannot accidentally consume the output it just produced.

Interface

Published topics

Per-plugin debug copies of the same state are published on state_estimation/<plugin_name>/pose and state_estimation/<plugin_name>/twist. They carry each plugin’s own view, before the authority check, which makes them the way to see what a non-authoritative plugin would have published. Rate is controlled by <plugin_name>.debug_publish_hz.

Subscribed topics and services depend entirely on the loaded plugin. See the plugin READMEs.

Parameters

Top-level parameters, defaulted in config/state_estimator_default.yaml:

The frame ids are not parameters of this package: as2::Node declares earth_frame_id, map_frame_id, odom_frame_id and base_frame_id once and shares them with the whole stack.

Plugin parameters live in a block named after the plugin:

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Changelog for package as2_state_estimator

1.1.3 (2025-07-23)

• [as2_state_estimator] In Raw Odometry Plugin, fix GPS Origin Info
• [as2_state_estimator] Fix odom topic default parameter in ground_truth_odometry_fuse plugin
• [as2_state_estimator] Replace timer for odometry callback in ground_truth_odometry_fuse
• [as2_state_estimator] Add ground truth and odometry fuse plugin for state estimator
• [as2_state_estimator] Set map to odom transform only if param is enable
• [as2_state_estimator] Enable gazebo TFs for all plugins
• [as2_state_estimator] Add ground truth and odometry fuse node
• [as2_state_estimator] Fix tf_handler instantiation in plugin base
• [as2_state_estimator] Improve mocap plugin
• [as2_state_estimator] Add earth to map transform using ROS 2 params in raw odometry plugin
• [as2_state_estimator] In raw_odometry plugin, replace frames checker from error to warning
• [as2_state_estimator] Use tf_handler instead of tf2_ros directly
• [aerostack2] Use as2::spingLoop without preset_loop_frequency
• [aerostack2] Maintainer and license tags update
• Contributors: Rafael Pérez, pariaspe

1.1.2 (2024-08-22)

1.1.1 (2024-08-20)

• [as2_state_estimator] Fix gtest warning: publisher already registered
• Contributors: Rafael Perez-Segui, pariaspe

1.1.0 (2024-08-08)

• [as2_state_estimator] map frame generates at the drone initial position
• [as2_state_estimator] Change gazebo tf parameter name
• [as2_state_estimator] update state estimator with new launch utils and new launchers for each plugin
• [as2_state_estimator] Code refactor, adding individually CMakeLists.txt and config for each plugin. Update launch using as2_core launch params utils
• [as2_state_estimator] Migrate to ament lint
• [as2_state_estimator] mocap_pose plugin changed to work with mocap4ros2
• Contributors: Javilinos, Miguel Fernandez-Cortizas, Rafael Perez-Segui, pariaspe

1.0.9 (2024-03-25)

• latlon2local function fails in z coordinate, added earth_to_map_height parameter
• raw odometry plugin should have a set gps origin
• Contributors: Javier Melero, Javilinos, Rafael Pérez

1.0.8 (2024-02-12)

1.0.7 (2024-02-04)

1.0.6 (2023-12-12)

1.0.5 (2023-11-08)

1.0.4 (2023-08-23)

1.0.3 (2023-08-22)

• Merge pull request #317 from aerostack2/316-tf2_geometry_msgs-dep Only use tf2_geometry_msgs library when needed
• only use library when needed
• Contributors: Miguel Fernandez-Cortizas, pariaspe

1.0.2 (2023-08-17)

• Merge pull request #279 from aerostack2/230-gps_support_for_ground_truth_plugin Add gps support for ground truth plugin
• Change origin param
• parameters added, compiling, add origin manually working
• gps support for ground truth plugin
• Contributors: Javilinos, Miguel Fernandez-Cortizas, RPS98, pariaspe

1.0.1 (2023-04-25)

• Merge pull request #223 from aerostack2/200-unify-maintainer-in-packagexmls Maintainer unified to CVAR-UPM
• Maintainer unified to CVAR-UPM
• Merge pull request #212 from aerostack2/211-nodes-should-use-aerostack2-node-create-timer-method-not-create-wall-timer Nodes use Aerostack2 Node Create Timer method, not create wall timer
• Change create wall timer to as2 create timer
• Contributors: Miguel Fernandez-Cortizas, RPS98, pariaspe

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