Error correction method for train speed measurement using Doppler radar in train control system

Train speed measurement takes an important position in the train control system. In the train speed measurement with velocity sensor and radar, the errors caused by radar installation are inevitable. In this paper, a method was proposed to correct the inherent deviation of the velocity measurement. Multiple round measurements on the fixed appropriate trial line are carried out to achieve wheel diameter calibration and store the speed value of velocity sensor and radar. Then, with the radar normalized speed calculation, uniform rate sampling and translation alignment, the velocity measurement values of sensor and radar are converted into the same coordinate system and the radar correct coefficient is determined. The accurate degree of correct coefficient is confirmed according to the speed error correlation between velocity sensor and radar in repeated trials. Practical verification has been tested in Beijing subway line and the statistical properties of speed deviation has been analysed with R language. The results indicate that the method we proposed can decrease the velocity error and improve the precision of radar measurement.