Fast and Precise Visual Rear Axle Calibration

The center of the rear axle represents the reference point for the motion and collision model of autonomous cars. This makes calibration of the rear axle to the sensor rig a fundamental prerequisite for planning and localization. Many commercial calibration systems are available, however they are spacious, difficult to set up and costly. So far, rear axle calibration got little attention in literature. Most approaches are odometry based which require time-consuming calibration drives. In this work we present a simple but effective approach for fast and precise sensor to rear axle calibration by calibrating the sensor rig of the vehicle together with external sensors that are used to determine the center points of the wheels. We show that this approach is not only highly practical but also precise while requiring a minimum of equipment.