Automatic signal strength map construction in indoor positioning system based on round trip time of flight measurements and inertial navigation

The accuracy of round trip time-of-flight indoor positioning system can be improved taking into account the measurements of received signal strength. This method requires prior knowledge about received signals strength statistics inside the building. In this paper we propose a method of automatic received signal strength map creation in time-of-flight based indoor positioning system with the help of odometry measurements. The proposed method is based on particle filter and uses distance and signal strength measurements together with the data from an embedded inertial measurement unit and the map of the building. The RSS coverage map consists on the set of discrete bins. When a particle visits a bin the RSS statistics in this bin is sequentially updated using Bayesian inference.