A Novel Parameter Estimation Scheme for Noncooperative Binary Offset Carrier Modulated Signals

The binary offset carrier (BOC) modulation has become one of the main global navigation satellite system (GNSS) modulations due to its strong anti-interference capability and high ranging accuracy. Noncooperative BOC parameter estimation is beneficial to signal acquisition, tracking, and the evaluation of mutual interference among different GNSSs. This paper proposes a novel parameter estimation scheme to improve the parameter estimation performance of BOC modulated signals under a low signal-to-noise ratio (SNR) scenario. The scheme is divided into two parts to realize the estimation of the carrier frequency, subcarrier frequency, and pseudo code rate of BOC modulated signals. The first part uses the spectral center method to estimate the carrier frequency, and the second part uses an improved peak-to-peak distance method to estimate the subcarrier frequency and pseudo code rate. Simulation results show that the spectral center method for carrier frequency estimation is more stable and easier to implement than the traditional square frequency method. Meanwhile, the improved peak-to-peak distance method for the estimation of subcarrier frequency and pseudo code rate has higher accuracy than the traditional peak-to-peak distance method under low SNR.