Common ROS topics

This page describes common ROS topics and messages for interprocess communication used by Aerostack. The goal of this set of topics is to facilitate the interoperability of the ROS nodes in Aerostack.

The content of part of these messages can be visualized with the help of the following tool:

• Alphanumeric viewer

Sensor Measurements

Sensor measurements are values corresponding to direct measurements recorded by sensors.

Topic name	ROS message	Description
sensor_measurement/camera	sensor_msgs/Image	Raw image data received from camera (a general camera).
sensor_measurement/camera/front	sensor_msgs/Image	Raw image data received from front camera.
sensor_measurement/camera/bottom	sensor_msgs/Image	Raw image data received from the bottom camera.
sensor_measurement/gps	sensor_msgs/NavSatFix	GPS (Global Positioning System) coordinates
sensor_measurement/magnetometer	geometry_msgs/Vector3Stamped	Magnetic field measurement
sensor_measurement/imu	sensor_msgs/Imu	Inertial Measurement Unit data
sensor_measurement/pressure	sensor_msgs/FluidPressure	Pressure
sensor_measurement/temperature	sensor_msgs/Temperature	Temperature reading
sensor_measurement/battery_state	sensor_msgs/BatteryState	Battery state
sensor_measurement/altitude	geometry_msgs/PointStamped	Altitude respect to the ground (in the message PointStamped, only the z value is used)
sensor_measurement/sea_level_altitude	geometry_msgs/PointStamped	Sea level altitude

Deprecated topics:

Topic name	ROS message	Description
sensor_measurement/position	geometry_msgs/PointStamped	Position measured by sensor (e.g., using RTK)
sensor_measurement/odometry	nav_msgs/Odometry	Odometry estimated by the platform
sensor_measurement/linear_speed	geometry_msgs/TwistStamped	Linear speed estimated by odometry (e.g. using visual odometry)
sensor_measurement/rotation_angles	geometry_msgs/Vector3Stamped	Rotation angles yaw (rad), pitch (rad), roll (rad)

Raw localization from aerial platform

Raw values corresponding to state estimation performed by the aerial platform.

Topic name	ROS message	Description
raw_localization/position	geometry_msgs/PointStamped	Position estimated by the aerial platform
raw_localization/odometry	nav_msgs/Odometry	Odometry estimated by the platform
raw_localization/linear_speed	geometry_msgs/TwistStamped	Linear speed estimated by odometry (e.g. using visual odometry)
raw_localization/rotation_angles	geometry_msgs/Vector3Stamped	Rotation angles yaw (rad), pitch (rad), roll (rad)

Ground truth

These values are considered as true reference. They can be used, for example, to compare with measured values and values obtained by estimation algorithms. These values are generated by simulators or by redundant sensors (e.g., Opti Track).

Topic name	ROS message	Description
ground_truth/pose	geometry_msgs/PoseStamped	Pose of the robot considered as true
ground_truth/speed	geometry_msgs/TwistStamped	Speed of the robot considered as true

Self Localization

These values correspond to the robot localization in the environment together with kinematic values (e.g., speed) as they are believed by the robot. These values may be obtained, for example, by fusing sensor measurements with the help of extended Kalman filters (EKF).

Topic name	ROS message	Description
self_localization/position	geometry_msgs/PointStamped	Estimated position (x,y,z). This information usually corresponds to position that is not refined using data from IMU
self_localization/pose	geometry_msgs/PoseStamped	Estimated pose
self_localization/speed	geometry_msgs/TwistStamped	Estimated speed
self_localization/flight_state	aerostack_msgs/flightState	Flight state (landed, hovering, ...)

Environment Understanding

These values correspond to characteristics of the environment and its elements as they are believed by the robot.

ROS message	Description
aerostack_msgs/DynamicObstacle.msg	Pair of messages geometry_msgs/PointStamped.msgs and shape_msgs/SolidPrimitive.msgs

Topic name	ROS message	Description
environment/costmap	nav_msgs/OccupancyGrid	Environment map represented as an occupancy grid (as used by Navigation Stack). This is not implemented yet.
environment/path_blocked_by_obstacle	std_msgs/Bool	This message notifies that the current path cannot be followed because an obstacle has been detected along the path.
environment/social_communication_channel	aerostack_msgs/SocialCommunicationStatement.msg	Communication channel with all messages sent between different robots.
environment/shared_robot_positions_channel	aerostack_msgs/SharedRobotPosition.msg	Communication channel with positions (x,y,z) shared by multiple robots.
environment/message_from_robot	aerostack_msgs/SocialCommunicationStatement.msg	Message sent from another robot to the own robot.
environment/dynamic_obstacles	aerostack_msgs/DynamicObstacles.msg	Dynamic obstacles in the environment.

Motion References

These messages are motion values to be considered as goals by quadrotor controllers.

ROS message	Description
aerostack_msgs/MotionControlMode.msg	Control mode of quadrotor PID controller

Topic name	ROS message	Description
motion_reference/pose	geometry_msgs/PoseStamped.msg	Pose reference for the controller. The following values from the message are used <x, y, z, yaw> (the values for <pitch, roll> are discarded)
motion_reference/speed	geometry_msgs/TwistStamped.msg	Speed reference for the controller. The following values from the message are used <d_x, d_y, d_z, d_yaw> (the values for <d_pitch, d_roll> are discarded)
motion_reference/path	nav_msgs/Path.msg	Reference path to be tracked by the quadrotor. The path is defined as a list of points. Each point is defined with a pose <x, y, z, yaw> (the values for <pitch, roll> are discarded)
motion_reference/trajectory	trajectory_msgs/MultiDOFJointTrajectory	Desired trajectory reference with points, velocities and accelerations.
motion_reference/remaining_path	nav_msgs/Path.msg	Remaining points of the path being followed by the multirotor. This list of points is updated each time a point is reached. When the remaining path is updated with an empty list of points, the reference path has been completed by the multirotor. Each point is defined with a pose <x, y, z, yaw> (the values for <pitch, roll> are discarded)
motion_reference/assumed_control_mode	aerostack_msgs/MotionControlMode.msg	Current control mode of the flight motion controller
motion_reference/assumed_pose	geometry_msgs/PoseStamped.msg	Pose reference assumed by the controller. For example, the controller can generate a variable pose to follow a particular trajectory.
motion_reference/assumed_speed	geometry_msgs/TwistStamped.msg	Speed reference assumed by the controller. For example, the controller can generate a variable speed to follow a particular trajectory.

Service Name	ROS service type	Description
set_control_mode	aerostack_msgs/SetControlMode	Sets control mode of the PID controller.

Actuator Commands

Actuator commands are messages that are accepted by the actuators of the robotic platform.

Topic name	ROS message	Description
actuator_command/motor_speed	mav_msgs/Actuators.msg	Motor speeds of multirotor.
actuator_command/thrust	mavros_msgs/Thrust Message	Actuator command for the multirotor specifying thrust (N: Newtons).
actuator_command/pose	geometry_msgs/PoseStamped	Actuator command for the multirotor specifying x, y, z, roll, pitch and yaw.
actuator_command/speed	geometry_msgs/TwistStamped.msg	Actuator command for the multirotor specifying dx, dy, dz, roll rate, pitch rate and yaw rate.
actuator_command/gimbal_speed	geometry_msgs/TwistStamped.msg	Actuator command for the camera gimbal.
actuator_command/flight_action	aerostack_msgs/FlightActionCommand.msg	Flight command specifying a qualitative action of the robot (take off, hover or land). This command can be interpreted by some aerial platforms (e.g. Parrot drones) but it is ignored by others.
actuator_command/odometry_actuation	[aerostack_msgs/OdometryActuation.msg]	Actuation command specifying an action on the odometry (e.g., reset or stop).

Deprecated:

Topic name	ROS message	Description
actuator_command/roll_pitch_yaw_rate_thrust	mav_msgs/RollPitchYawrateThrust.msg	Actuator command for the multirotor specifying roll (rad), pitch (rad), yaw rate (rad/s) and thrust (N: Newtons).
actuator_command/roll_pitch	geometry_msgs/PoseStamped.msg	Actuator command for the multirotor specifying roll and pitch (the rest of values for <x, y, z, yaw> are discarded)
actuator_command/altitude_rate_yaw_rate	geometry_msgs/TwistStamped.msg	Actuator command for the multirotor specifying rates for altitude (d_z) and yaw (d_yaw) (the rest of values for <d_x, d_y, d_yaw, d_pitch, d_roll> are discarded)