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The localization system is responsible for merging date from the various sensors that provide position and orientation information (or pose), and then publishing the posterior best estimate of the Robot's pose to the rest of the system. Assumed sensors include the Stargazer (indoor) global positioning system and wheel odometers. Pose can also be defined by the user.

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API Documentation

localization_cu

localization_cu is a node that subscribes to global pose and local pose data, it uses this to update an internal best estimate of the true pose in the /map_cu coordinate frame and then publishes that for other nodes to use.

Subscribed Topics

/cu/odometer_pose_cu (geometry_msgs/Pose2D)

• 2D pose created using only the wheel odometers in the local coordinate system used by the irobot create itself.

/cu/user_pose_cu (geometry_msgs/PoseStamped)

• a user defined pose, used to manually define the robots starting position with a GUI in map coordinates (/map_cu).

/cu/stargazer_pose_cu (geometry_msgs/Pose2D)

• Pose from (indoor) global positioning system in world coordinates (/world_cu).

Published Topics

/cu/pose_cu (geometry_msgs/PoseStamped)

• The robot's best estimate of where it is, given all pose data, in map coordinates (/map_cu).

Services

/cu/get_pose_cu (localization_cu/GetPose)

• The robot's best estimate of where it is, given all pose data, in map coordinates (/map_cu).

Parameters

~using_gps (bool, default: true)

• When true, causes localization_cu to wait for gps data before publishing pose.

~max_pose_jump_ratio (double, default: 2 (m))

• (meters) if pose jumps more than max_pose_jump_ratio * (local movement), then global pose is dropped (used to prune erroneous gps data).

~odometer_pose_x_init (double, default: 0 (m))

• Initial x value (meters) for the odometer pose (in the internal frame used by the irobot create robot).

~odometer_pose_y_init (double, default: 0 (m))

• Initial y value (meters) for the odometer pose (in the internal frame used by the irobot create robot).

~odometer_pose_theta_init (double, default: 0 (rad))

• Initial theta value (radians) for the odometer pose (in the internal frame used by the irobot create robot).

~posterior_pose_x_init (double, default: 0 (m))

• Initial x value (meters) for the robot pose in the world coordinate frame (/world_cu).

~posterior_pose_y_init (double, default: 0 (m))

• Initial y value (meters) for the robot pose in the world coordinate frame (/world_cu).

~posterior_pose_theta_init (double, default: 0 (rad))

• Initial theta value (radians) for the robot pose in the world coordinate frame (/world_cu).

prairiedog/using_tf (bool, default: true)

• When true, the tf ROS package is used to facilitate coordinate transformations.

Required tf Transforms

/world_cu → /map_cu

• Transformation between world and map

Provided tf Transforms

/world_cu → /robot_cu

• Transformation between world and robot