Hybrid TOA/TDOA based unified Kalman tracking algorithm for wireless networks

Location estimation and tracking for the mobile stations have attracted a significant amount of attention in recent years. Moreover, different types of signal sources are considered available to provide the measurement inputs for location estimation and tracking. In this paper, a hybrid unified Kalman tracking (HUKT) technique is proposed to provide an integrated algorithm for precise location tracking based on both the time-of-arrival (TOA) and time-difference-of-arrival (TDOA) measurements. A new variable is incorporated as an additional state within the Kalman filtering formulation in order to consider the nonlinear behavior for wireless location estimation. Comparing with existing schemes, numerical results illustrate that the proposed HUKT algorithm can achieve enhanced accuracy for mobile location tracking, especially under the environments with insufficient number of signal sources in a single signal path.