An Iterative Phase Shifters Online Calibration Technique for Automotive Radar Systems

Calibration of automotive radar systems is of utmost importance to guarantee optimal sensor performance all along its life cycle. Yet, the classical end-of-line calibration neglects the drifting nature of addressed errors. Furthermore, newly adopted phase-coded modulation techniques for frequency-modulated continuous-wave (FMCW) radar create a new calibration challenge at the phase shifters level. In this paper, we present an iterative online calibration method for transmit phase shifters tackling both topics at once. The performance of the presented iterative method is validated with measurements on an already available radar setup showing that phase shifter errors could be kept below 0.2° after convergence at any stage of the radar’s life cycle. On top of that, this method does not require any additional hardware components.