A smartphone-based indoor positioning system using fuzzy theory and WLAN mapping algorithm

As we all know, the accuracy of GPS become worse indoors due to the satellite signal attenuation. However, people spend most of his or her time in the indoor environment and the location-based service is needed in the indoor environment. Hence, many indoor positioning techniques have been researched to provide location-based service for visitors in public buildings such as museums, galleries, etc. However, the distinguish of human´s moving patterns and initial position detection are two difficult problems in Pedestrian Dead Reckoning (PDR) system. Therefore, A smartphone-based indoor positioning system (called Improved Pedestrian Dead Reckoning, IPDR) using fuzzy theory and WLAN mapping algorithm is presented to solve these problems. In our proposed system, we propose a method called fuzzy step length detection which can distinguish five different human´s moving patterns and handle various ways of holding the phone. The WLAN mapping algorithm could calculate the initial position. Calibrated position can be obtained from the IPDR position and the mapping position from WLAN map acquired in advance. The performance of our IPDR system is verified via a set of simulations and the result is positive.