Calibration of optical odometer's scale factor with tire inflation temperature

For reducing the influence of tire inflation temperature on optical odometer's scale factor and improving the position accuracy of dead reckoning system, the error model of dead reckoning is analyzed and the carrier-phase differential GPS (CDGPS)-based calibration method for odometer's scale factor is presented. Based on the high precision position output of CDGPS, and combining with the measurements of strapdown inertial navigation system (SINS) and odometer, a Kalman filter is used to estimate the odometer's scale factor which is changed with tire inflation temperature. Experiment results show that this method can accurately calibrate the scale factor's characteristics, and the scale factor is linear to tire inflation temperature at the given initial inflation pressure. Vehicle navigation experiment is implemented according to the calibrated odometer's scale factor. Under good road conditions, the latitude error is reduced to 5 m from 28 m and the longitude error is reduced to 10 m from 65 m when the travel distance is 78 km.