Precise Dead-reckoning Using Portable Navigation Device in Urban Environments

This paper presents a novel method for dead-reckoning using portable navigation devices (PND) for land vehicle. In recent years, various PND which are low cost and easily mounted are becoming popular as a vehicle navigation device. However, because it cannot obtain wheel speed information from a vehicle, it is difficult to estimate accurate vehicle speed and the error of dead-reckoning is rapidly increased. Accordingly, in this study two approaches for improving dead-reckoning with PND is proposed. The first one is the accurate speed estimation using time-series tightly coupled integration of accelerometer, gyro, and GPS Doppler, which robustly works in urban area. And the second one is the correction of trajectory error using real-time backward processing that reduces accumulated error of the dead-reckoning. The experimental result shows that the error of dead-reckoning was reduced to 1/4 of the previous method in urban area.