A Rubidium Atomic Frequency Standard with Stability at $10^{ - 15}$ Level Operated Under Atmospheric Condition

Abstract

Among several kinds of traditional atomic clocks, rubidium atomic clock shows more extensive applications for its small size, low power and simple structure. In last 20 years, driven by the demands of satellite navigation and relevant fields, the Rb atomic clock has been greatly improved on its frequency stability. Now the long-term stability of satellite-borne Rb atomic clock is better than $5 \times 10^{ - 15}$ at one day. However, when Rb clock runs under atmospheric condition, its long-term stability performance deteriorate seriously. There is a 10 to 100 times deterioration at $10^{4}$ s and one day, which makes Rb clock impossible to reach $10^{ - 15}$ level. For solving these problems, to develop a high-stability, low-drift and compact-structure type of high performance Rb clock which could fit the atmospheric environment, we conducted a sufficient research on high-performance Rb clock’s environment adaptation. Finally, we developed a prototype whose stability reached $6.5 \times 10^{ - 13} /\sqrt \tau$, $7.0 \times 10^{ - 15}$ at $10^{4}$ s and $5.0 \times 10^{ - 15}$ at one day.