ED Localization

A fast particle filter implementation and sensor models for localizing a robot which always take into account the most recent state of the world. This means that if the world representation improves while the robot is running, localization becomes better. The localization module is more efficient and accurate than the well-known AMCL-module and no separate occupancy grid is needed.

Installation

Requirements:

• Ubuntu (24.04 or newer)
• ROS 2 (Jazzy or newer)
• ED (https://github.com/tue-robotics/ed.git)
• A 2D Range Finder which scans in a plane parallel to the floor
• A TF tree containing transforms from the robots’ odometry frame to the laser range finder frame

We assume you have successfully installed ROS 2 and set-up a colcon workspace. Check out the following packages in your workspace:

cd <your_colcon_workspace>/src
git clone https://github.com/tue-robotics/ed_localization.git

Install the dependencies by resolving them via rosdep, then compile:

cd <your_colcon_workspace>
colcon build --packages-up-to ed_localization

Running the tests additionally needs the tue-robotics ament_lint fork and tue_lint_config in the workspace, since the linters are invoked with options that are not in upstream ament_cmake_clang_format/ament_cmake_clang_tidy:

colcon test --packages-select ed_localization && colcon test-result --verbose

Plugins

Both plugins are ED plugins, loaded by the ED server through pluginlib and configured from ED’s own configuration file:

• ed_localization/localization — particle filter localization against the world model, publishing the map -> odom transform and the particle cloud on ed/localization/particles.
• ed_localization/localization_tf — sets the robot entity pose from an externally provided TF tree.

Remembering the pose across restarts

ed_localization/localization periodically writes the robot pose in the map frame to disk and reads it back on start-up, so a restarted ED resumes where it left off instead of at the origin. In ROS 1 this used the global parameter server, which ROS 2 does not have.

The default follows ROS 2’s own ROS_HOME/~/.ros convention and is keyed by robot_name, so two robots sharing a home directory do not overwrite each other. Set initial_pose_file explicitly when ED runs as a system user with no usable $HOME — for example a systemd unit with StateDirectory=ed_localization, giving /var/lib/ed_localization.

The file uses the same schema as the initial_pose config group, plus the frame it was recorded in:

initial_pose:
    map_frame: map
    rz: -0.0542
    x: -0.0503
    y: -0.0578

A stored pose is rejected when map_frame does not match the configured map_frame, because seeding the filter with a pose from a different environment is a narrow, confidently wrong start — worse than falling back to the config default. Writes go to a sibling .tmp file and are renamed into place, so a crash mid-write leaves the previous pose intact rather than a truncated file.

The initial pose is taken from the first source that has one: the initial_pose.x/.y/.yaw node parameters (a launch-time override), then the stored file, then the initial_pose group in the ED config, and finally the origin. All four express the robot pose in the map frame.

Tutorial

All ED tutorials can be found in the ed_tutorials package: https://github.com/tue-robotics/ed_tutorials.git