Unambiguous Acquisition/Tracking Technique for High-Order Sine-Phased Binary Offset Carrier Modulated Signal

The binary offset carrier (BOC) modulated signals have been widely employed in global navigation satellite systems due to its outstanding performance. The BOC signal can share frequency spectrum with traditional BPSK signal, meanwhile provide better code tracking accuracy. However, the multiple peaks auto-correlation function of BOC signal results in the acquisition and tracking ambiguity problem. Several methods have been proposed to remove the ambiguity, but they mainly focus on the low modulation order BOC signal, and not efficient enough for high-order BOC signal. In this paper, we propose an unambiguous acquisition/tracking technique for high-order sine-phased BOC signal. The key of this technique is to design a new local auxiliary signal. With the help of the cross-correlation function between the BOC signal and the local auxiliary signal, we obtain a combined correlation function without major positive side peaks. The proposed acquisition and tracking schemes are presented. The theoretical false alarm and detection performance are given, and the theoretical code tracking error in thermal noise is derived. The performance of the proposed method is analyzed by theory and simulation. Results show that for high-order sine-BOC signal, the proposed technique can remove the ambiguity threat. Compared with the existing methods, our method has a significant improvement in terms of acquisition sensitivity and code tracking performance.