Error Sources When Land Vehicle Dead Reckoning with Differential Wheelspeeds

This paper compares a differential wheelspeed–based dead-reckoning system with a gyro-based system for land navigation. Test results show that the two schemes perform equally well when modeling assumptions hold, such as when navigating smooth road surfaces. However, the wheelspeed-heading estimator's position errors grow about twice as fast as the gyro-based system's when navigating speed bumps and uneven road surfaces. In contrast to statements made in the literature, increasing the resolution of the stock wheelspeed sensors by an order of magnitude does not increase the positioning accuracy of either estimator, and longitudinal slip of the vehicle tires does not appear to be a dominant error source. Ultimately, the limiting factor for dead-reckoning performance appears to be road surface unevenness.