Self-Calibration of a 3-D-Digital Beamforming Radar System for Automotive Applications With Installation Behind Automotive Covers

Given the complexity of a radar system with digital beamforming, a number of error influences can appear due to hardware imperfections, temperature drift, and aging. These errors can result in a reduced target detection probability or even lead to false detections. For automotive driver assistance applications, there is a growing demand for hidden integration of radar systems. When installed behind a painted bumper or design radome, additional performance degradation may occur. First, the hardware imperfections according to their appearance in the presented radar system and their effects are analyzed with respect to the angular spectrum estimation. A software-based self-calibration algorithm is proposed and evaluated by means of simulation and measurement. Finally, the extended performance capability of the self-calibration procedure to compensate additional error components from automotive covers is investigated by means of a painted bumper in front of the radar sensor.