  Increasing sources of sensor measurements and prior knowledge have become
available for indoor localization on smartphones. How to effectively utilize
these sources for enhancing localization accuracy is an important yet
challenging problem. In this paper, we present an area state-aided localization
algorithm that exploits various sources of information. Specifically, we
introduce the concept of area state to indicate the area where the user is on
an indoor map. The position of the user is then estimated using inertial
measurement unit (IMU) measurements with the aid of area states. The area
states are in turn updated based on the position estimates. To avoid
accumulated errors of IMU measurements, our algorithm uses WiFi received signal
strength indicator (RSSI) to indicate the vicinity of the user to the routers.
The experiment results show that our system can achieve satisfactory
localization accuracy in a typical indoor environment.
