Sensor assisted 3D personal navigation on a smart phone in GPS degraded environments

Compared to 2D navigation, 3D navigation requires much better performance of locating and heading. In an urban environment, the signals from a built-in GPS on a smart phone are always so weak that it causes considerably low position and heading accuracy. To address this issue and improve the user experience, two contexts, Navigation and Look-Around, are defined in 3D personal navigation. The following methods are applied in this paper: 1) the built-in accelerometer is used for recognizing motion modes of an end-user; 2) a map matching algorithm is implemented for forcing positioning results to be attached on the road; 3) A Bayesian network based heading change detection algorithm is developed by using the built-in digital compass. Finally, the demonstrations in Shanghai World EXPO 2010, China, and Tapiola, Finland are presented.