Performance Analysis of Space Cold Atomic Clock Based on In-Situ Atomic Detection

The cold atomic clock, which uses laser cooling techniques, is expected to obtain more accurate time-frequency reference in the space microgravity environment than on the earth. This paper proposes a scheme for a new type of space cold atomic clock based on in-situ atomic detection. This design realizes the capture, cooling, state selection, microwave interrogation, and quantum state detection of cold atoms in a microwave cavity. Further, this design allows for a shorter clock cycle, higher time duty cycle for microwave interrogation, and a more compact structure than our previous space cold atomic clocks. Using a Boitier a Vieillissement Ameliore (BVA) crystal oscillator as a local oscillator, we analyze and estimate the stability of the cold atomic clock due to the Dick effect and quantum projection noise. In addition, we estimate sources affecting the uncertainty of the cold atomic clock. The results indicate that the proposed space cold atomic clock is expected to reach a stability of 5.9 x 10(14) tau(-1/2) and uncertainty of 1 x 10(-16). These results arc superior to those of existing cold atomic microwave clocks which use a BVA crystal oscillator as a local oscillator.