Ultrasonic satellite system moving object positioning by extended Kalman filter

This paper presents positioning algorithms for an ultrasonic satellite system (USAT) consisting of multiple ultrasonic transmitters and receivers in buildings. The previously used inverse matrix method of calculating USAT positions suffers from problems related to transmitter layout, and the method is sensitive to sensor noise. To solve these problems, a geometric approach with verification by a comparison of simulations with the inverse matrix method, is suggested. However, when an object is moved quickly, the positioning error is increased. The moving object positioning algorithm with an extended Kalman filter (EKF), which takes account of the dynamics of the moving object, is therefore proposed for estimating USAT positioning during movement. The accuracy of the proposed algorithm is evaluated by simulations and experiments. The experimental results show that the proposed algorithm gives a better performance for dynamic states.