Fast Time-Frequency Synchronization Method Based on Digital Phase Offset Generator Model

Time-frequency synchronization technology is fundamental to the global satellite navigation system (GNSS) for positioning, navigation, and timing (PNT). The synchronization speed of time-frequency synchronization systems is a key performance indicator for PNT services and a standard for comparing the performance of major GNSS systems worldwide. As an important component of the time-frequency synchronization system, the phase offset generator directly affects the accuracy and speed of time-frequency synchronization. Currently, there is a lack of research on the digital phase offset generator model, making it difficult to design optimal parameters of model and resulting in slow synchronization speed in the time-frequency synchronization system. This paper focuses on establishing a model for digital phase offset generator and designing a fast loop filter algorithm to improve the convergence speed of a time-frequency synchronization system. Experimental results show that using this research method, the frequency and phase adjustment time of the time-frequency synchronization system is 1 second, which is one order of magnitude compared to existing systems.