Rapid Reacquisition Algorithm with Vector Tracking Loop in Indoor Pseudolite Applications

The tracking loop always loses its lock in the indoor independent pseudolite positioning system when the weak signals are blocked by the strong signals frequently. Aiming at solving this problem, this paper proposes a rapid reacquisition algorithm with vector tracking loop (VTL). The algorithm utilizes the tracking information from all channels to aid the processing of individual channel through the extended Kalman filter (EKF), and it can obtain a stable tracking control input. A simulation has been made to compare the tracking ability of the blocked signals between scalar tracking loop (STL) and vector tracking loop (VTL). Furthermore, an independent indoor pseudolite positioning system has been set up. The experiments prove that, in rapid reacquisition lost signals, the performance of VTL is much more effective than the STL’s.