Automotive Radar-Based Hitch Angle Tracking Technique for Trailer Backup Assistant Systems

We propose a technique for trailer angle detection (TAD) for use in advanced trailer backup assistance systems (TBAS) for semi-autonomous or fully autonomous backup maneuvers. TBAS incorporates a combined trailer-tow-vehicle kinematic model, which requires an estimate of the hitch-angle. The proposed radar-based TAD model processes reflections acquired from the mmWave radars situated at the rear side of the vehicle to detect the trailer and track its orientation to the tow-vehicle. This technique is based on the tracking of individual points in the merged radars point-cloud. Each tracked point is considered as a hitch-angle estimator. Using the current and past position information of a point, the model estimates the current hitch-angle. To offer an accurate and reliable estimation for the hitch-angle, the model fuses the estimated hitch-angle by all estimators and the yaw rate of the vehicle. The model employs a Kalman filter to track each radar point, which is robust to the noisy radar measurements. In the presence of strong and persistent reflections from the trailer, the model can track the trailer successfully and return the hitch-angle with a reliability measure equal to 90%. For a less common flat trailer with inconsistent radar reflective points, the measured reliability drops to 72%. The model is implemented in real-time with an expected processing time of 4 ms per epoch.