fake_localization

A ROS node that simply forwards odometry information.

This version was migrated by Juan Francisco Rascon Crespo to ROS2 Humble distro from the original fake_localization package developed by Ioan A. Sucan which is described in ROS Wiki and whose source code is available in this GitHub repository and in ROS Noetic distro (ROS1).

Description

The fake_localization package provides a single node, fake_localization, which substitutes for a localization system, providing a subset of the ROS API used by amcl. This node is most frequently used during simulation as a method to provide localization based on perfect odometry in a computationally inexpensive manner. Specifically, fake_localization converts odometry data into pose, particle cloud, and transform data of the form published by amcl.

The node fake_localization is also available as a composable node, fake_localization::FakeLocalization, which can be launched dynamically inside a ROS container and use intra-process communication.

Nodes

fake_localization substitutes for a localization system, providing a subset of the ROS API used by amcl.

Subscribed Topics

• odom (nav_msgs::msg::Odometry message type)
  • The position of the robot as published by a simulator.
• initialpose (geometry_msgs::msg::PoseWithCovarianceStamped message type)
  • Allows for setting the pose of fake_localization using tools like rviz2 to give a custom offset from the ground truth source being published.

Published Topics

• amcl_pose (geometry_msgs::msg::PoseWithCovarianceStamped` message type)
  • Just passes through the pose reported by a simulator.
• particlecloud (geometry_msgs::msg::PoseArray message type)
  • A particle cloud used to visualize the robot's pose in rviz2.

Parameters

• odom_topic (string, default: "odom")
  • The name of the topic of the robot's odometry to be subscribed.
• odom_frame_id (string, default: "odom")
  • The name of the odometric frame of the robot.
• global_frame_id (string, default: map)
  • The frame in which to publish the global_frame_id -> odometry_frame_id transform over tf. New in 1.1.3
• base_frame_id (string, default: base_link)
  • The base frame of the robot. New in 1.1.3
• delta_x (double, default: 0.0)
  • The x offset between the origin of the simulator coordinate frame and the map coordinate frame published by fake_localization.
• delta_y (double, default: 0.0)
  • The y offset between the origin of the simulator coordinate frame and the map coordinate frame published by fake_localization.
• delta_yaw (double, default: 0.0)
  • The yaw offset between the origin of the simulator coordinate frame and the map coordinate frame published by fake_localization.
• transform_tolerance (double, default: 0.1)
  • The default tf lag in seconds.

Provided tf Transforms

<global_fr> -> <odom_fr> passed on from the simulator over tf.

Notes

Please, do read the comments in the file fake_localization_ros.cpp, which are quite didactics and helpful to understand how this node works internally.