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Data message for radars#

Summary#

To sum up, Autoware uses radar data type as below.

Radar data message for pointcloud#

Message definition#

std_msgs/Header header
radar_msgs/RadarReturn[] returns

# All variables below are relative to the radar's frame of reference.
# This message is not meant to be used alone but as part of a stamped or array message.

float32 range                            # Distance (m) from the sensor to the detected return.
float32 azimuth                          # Angle (in radians) in the azimuth plane between the sensor and the detected return.
                                         #    Positive angles are anticlockwise from the sensor and negative angles clockwise from the sensor as per REP-0103.
float32 elevation                        # Angle (in radians) in the elevation plane between the sensor and the detected return.
                                         #    Negative angles are below the sensor. For 2D radar, this will be 0.
float32 doppler_velocity                 # The doppler speeds (m/s) of the return.
float32 amplitude                        # The amplitude of the of the return (dB)

Radar data message for tracked objects#

Message definition#

# Object classifications (Additional vendor-specific classifications are permitted starting from 32000 eg. Car)
uint16 NO_CLASSIFICATION=0
uint16 STATIC=1
uint16 DYNAMIC=2

unique_identifier_msgs/UUID uuid            # A unique ID of the object generated by the radar.
                                            # Note: The z component of these fields is ignored for 2D tracking.
geometry_msgs/Point position                # x, y, z coordinates of the centroid of the object being tracked.
geometry_msgs/Vector3 velocity              # The velocity of the object in each spatial dimension.
geometry_msgs/Vector3 acceleration          # The acceleration of the object in each spatial dimension.
geometry_msgs/Vector3 size                  # The object size as represented by the radar sensor eg. length, width, height OR the diameter of an ellipsoid in the x, y, z, dimensions
                                            # and is from the sensor frame's view.
uint16 classification                       # An optional classification of the object (see above)
float32[6] position_covariance              # Upper-triangle covariance about the x, y, z axes
float32[6] velocity_covariance              # Upper-triangle covariance about the x, y, z axes
float32[6] acceleration_covariance          # Upper-triangle covariance about the x, y, z axes
float32[6] size_covariance                  # Upper-triangle covariance about the x, y, z axes

Message usage for RadarTracks#

  • Object classifications

In object classifications of radar_msgs/msg/RadarTrack.msg, additional classifications label can be used by the number starting from 32000.

To express for Autoware label definition, Autoware defines object classifications for RadarTracks.msg as below.

uint16 UNKNOWN = 32000;
uint16 CAR = 32001;
uint16 TRUCK = 32002;
uint16 BUS = 32003;
uint16 TRAILER = 32004;
uint16 MOTORCYCLE = 32005;
uint16 BICYCLE = 32006;
uint16 PEDESTRIAN = 32007;

For detail implementation, please see radar_tracks_msgs_converter.

Note#

Survey for radar message#

Depending on the sensor manufacturer and its purpose, each sensor might exchange raw, post-processed data. This section introduces a survey about the previously developed messaging systems in the open-source community. Although there are many kinds of outputs, radar mainly adopt two types as outputs, pointcloud and objects. Related discussion for message definition in ros-perception are PR #1, PR #2, and PR #3. Existing open source softwares for radar are summarized in these PR.