Coupled sonar inertial navigation system for pedestrian tracking

This paper presents a novel method for indoor pedestrian tracking using inertial sensing and sonar sensors. The zero velocity updating technique, which is used to enhance the performances of inertial sensing, cannot observe heading, resulting in a horizontal position drift. Sonar sensors are used as complementary technique to correct heading. The main idea is to extract a partial map of surrounding walls. Sonar returns are processed via the Hough transformation to extract wall segments (line features). The first detected segments will initiate a wall landmark. The pedestrian relative distance to next detected segments that are associated to a stored wall landmark, is considered to be his relative distance to that wall. An extended Kalman filter based solution to Bearing-Range simultaneous localization and mapping is used. The state vector is a concatenation of pedestrian position and positions of first points of each stored wall landmark, to which the virtual Bearing-range measurements are pointing. Both inertial and coupled sonar inertial tracks are visually compared to the true trajectory.