Location awareness and navigation are becoming one of the most important features in
mobile phones and smartphones. Personal navigation and location based services are
enlarging the scope of mobile applications. GPS is the most efficient positioning technology.
Thanks to the reduction in the size of the GPS receivers and the integration of GPS with
mobile phones, GPS is one of the most important service providers in LBS. By the way, since
mobile phones and smartphones usually have relatively low cost GPS chips, the performance
of locating accuracy is highly dependent on environmental factors. In addition, the accuracy
of GPS varies depending on the number of GPS satellites and is reduced in GPS interfering
spots such as in a forest or around buildings. This paper proposes a localization improvement
algorithm in GPS interfering spots by integrating information of multiple sensors in
smartphones. The proposed algorithm is implemented in a smartphone and the performance
is evaluated on a campus. The proposed algorithm has better performance than only the GPS
location information in GPS interfering spots and maintains reasonable performance in open
spaces where the GPS receiver is accurate.