Coordinate frames used in this dataset include sensor frames, the body frame, the local frame, the GPS frame and the global frame.
The body frame on the vehicles defined with the X axis pointing forward, the Y axis to the right, and the Z axis pointing down. The origin of the body frame is defined as the center of the rear axle of the vehicle.
Sensors record data relative to an internal sensor frame that then needs to be related to the body frame. The position of a sensor frame relative to the vehicle body frame is described using the extrinsic parameters.
The GPS global frame used within the dataset makes use of the WGS-84 oblate spheroid model of the Earth.