Unambiguous tracking techniques for Galileo BOC(1,1) signals

Because of the multi-peak auto-correlation function, false locking may happen in Galileo BOC code tracking process. Firstly, the shortcoming of the classic early-late-gate tracking loop for BOC code tacking is discussed. Then, new tracking loops which combined multi-early-late-gates are designed in this paper to remove the ambiguity, and the combining coefficients of the two and three early-late-gates combined tracking loops are derived theoretically. Simulation results show that these two combined tracking loops can eliminate false lock points, and improve the tracking stability and linearity of the loops obviously, especially for three early-late-gates tracking loop.