  A reliable self-contained navigation system is essential for autonomous
vehicles. In this study, we propose a multiple microelectromechanical system
(MEMS) inertial measurement unit (IMU)-based dead reckoning (DR) solution for
wheeled vehicles. The IMUs are located at different places on the wheeled
vehicle to acquire various dynamic information. In the proposed system, at
least one IMU has to be mounted at the wheel to measure the wheel velocity,
thus, replacing the traditional odometer. The other IMUs can be mounted on
either the remaining wheels or the vehicle body. The system is implemented
through a decentralized extended Kalman filter structure in which each
subsystem (corresponding to each IMU) retains and updates its own states
separately. The relative position constraint between the IMUs is exploited by
fusing the IMU positions to calculate the coordinates of the reference point,
which is treated as an external observation of the subsystems. Specially, we
present the DR systems based on dual wheel-mounted IMUs (Wheel-IMUs), one
Wheel-IMU plus one vehicle body-mounted IMU (Body-IMU), and dual Wheel-IMUs
plus one Body-IMU as examples for analysis and experiments. Field tests
illustrate that the proposed multiple IMU-based DR system statistically
outperforms the single Wheel-IMU based DR system in positioning and heading
accuracy. Moreover, of the three multi-IMU configurations, the one Body IMU
plus one Wheel-IMU design obtains the minimum drift rate.
