A Low-Processing-Rate Dual BPSK Tracking Method for BOC Modulated Signals

Abstract

Among the existing wideband processing methods for binary offset carrier (BOC) signals, dual binary phase-shift keying (BPSK) tracking (DBT) features the interoperability with traditional BPSK tracking and flexible switching between single-sideband and wideband tracking modes. However, due to the large bandwidth of entire BOC signal, the DBT method requires a high signal sampling and processing rate, resulting in high computational burden. This letter proposes a low-processing-rate dual BPSK tracking (LPR-DBT) method to tackle this problem. A preprocessing unit is proposed to be added between the ADC and DBT correlator channels under the constraint of retaining the subcarrier ranging information. It converts both the upper and lower sidebands of BOC signal to near-zero frequency, respectively, and then decimates them. This significantly reduces the correlator channel processing rate without ranging performance loss. It is worth emphasizing that the delays and phase shifts introduced by the preprocessing to each sideband are carefully considered and dealt with to ensure the relationship between two sidebands required by the DBT method is not destroyed.