Improved Vehicle Positioning in Urban Environment through Integration of GPS and Low-Cost Inertial Sensors

Accurate and continuous position calculation is a key task for vehicle navigation and telematics applications. In most portable car navigation and telematics devices, the position is calculated based only on GPS data. However, in urban canyons stand-alone GPS suffers signal masking and reflections of the signal from buildings, large vehicles, and other reflective surfaces. Driving tests in such metropolises as Hong Kong, Tokyo, and New York show that the chance of receiving four GPS satellites required for navigation can be as low as 20% of total driving time [1]. Even when four or more satellites are available, strong multipath effect might cause a positioning error of more than 100 m.