An Improved Unambiguous CBOC Signal Tracking Scheme in the Galileo System

Based on the cancellation and reinforcement of the autocorrelation side-peaks and main-peak, respectively, this paper proposes an improved unambiguous tracking scheme for composite binary offset carrier (CBOC) signals used in the Galileo system. Dividing the CBOC autocorrelation into multiple partial correlations, first, we obtain individual correlation components making up the autocorrelation side-peaks and main-peak. Then, we re-combine the components to cancel out the side-peaks, and at the same time, to reinforce the main-peak, thus yielding a correlation function with no side-peaks and a sharp mainpeak. Numerical results demonstrate that the proposed scheme provides a significant improvement in tracking performance over the conventional schemes. Keywords–Global navigation satellite system (GNSS); Composite binary offset carrier (CBOC); Signal tracking; Ambiguity