Automobile Doppler speedometer

Abstract

Cars with electronically controlled all-wheel drive, antiblocking systems or anti slip control require speed sensors, measuring true speed over ground (TSOG). By comparing wheel speed and TSOG value, information about blocking or slipping rates is obtained. A Doppler radar sensor for TSOG measurements is presented, based on millimeter-wave frontends and digital processing of baseband signals. For the estimation of the Doppler frequency an FFT-based method extended by sensor-model-based algorithms for postprocessing is used. Measurement results are given, showing excellent system performance even under adverse environmental conditions.