GPS校频系统的优化带宽设计

Optimal bandwidth design for low noise GPS frequency calibration system

精密时间频率在现代社会有着重要的作用。本文设计了一种将远距离传输GPS标准秒脉冲信号的优良长稳性能与可调本地频率源的优良短稳性能结合起来的锁相系统,得到了高稳定度、高精度的时间频率标准源。论文对GPS校频系统进行了合理简化,建立起易于分析的数学模型,然后对校频系统中关键的难点——噪声抑制问题进行了重点分析,进而设计了系统的优化带宽,并进行了仿真和实验验证。结果表明了优化带宽设计的合理性,满足了GPS校频系统的精度要求。

precise time and frequency are crucial in many application fields of industry, traffic,telegraphy and military affairs. In this paper, a high stability and precision frequency source is developed using a PLL framework, which synthesizes the excellent characteristic of long term stability of a standard 1PPS transmitted from a long distance with the excellent characteristic of short term stability of a local frequency source. The actual GPS frequency calibration system is properly simplified to make it easier to analyze, then a frequency calibration mathematic model is established based on above analysis. After a detail analysis on the key problem of GPS frequency calibration system-noise suppression, an optimal bandwidth is designed in order to achieve very low noise. Simulation and experiments were carried out; final results prove that the proposed optimal bandwidth design is proper, which meets the requirement of high precision frequency cali- bration system.