An Array Nonlinear Kalman Tracker for Indoor GPS Signal
To implement indoor GPS signal tracking in standalone mode when the tracking loop is unlocked and data bit edge is unknown, the paper develops a modified Viterbi Algorithm (MVA) based on dynamic programming, and it was applied for GPS bit synchronization. Besides, two combination carrier tracking schemes based on Central Difference Kalman Filter (CDKF) and MVA module were designed for indoor GPS signal. The testing results indicate that the methods can successful detect bit edge position with high detection probability whether or not the tracking loop is locked. The co-operational tracking scheme is still able to perform when the signal quality deteriorate.
J. C. Ding et al., "An Array Nonlinear Kalman Tracker for Indoor GPS Signal", Applied Mechanics and Materials, Vols. 44-47, pp. 3864-3868, 2011