Amplitude Modulation Noise Suppression of Dynamic Atom Gravimeters

TL;DR

This paper identifies amplitude modulation noise as a key factor degrading dynamic atom gravimeter performance and proposes a fitting-based suppression method that significantly improves measurement precision.

Contribution

It introduces a novel model and fitting method to suppress amplitude modulation noise in dynamic atom gravimeters, enhancing their accuracy.

Findings

Suppressed AMN from 0.11 to 0.038 using the proposed method.

Improved fringe phase resolution from 0.244 rad to 0.092 rad.

Reduced dynamic gravity measurement noise from 2.69 mGal to 1.68 mGal.

Abstract

Dynamic atom gravimeters enable absolute gravity measurements on moving platforms. However, their performance is severely degraded due to the complex dynamic environment. This paper finds that the amplitude modulation noise (AMN) is a key factor contributing to the degradation of gravity measurement performance. We find that the AMN is induced by the cold atomic cloud trajectory and velocity variation. We build a model to illustrate the principles and magnitude of AMN arising from various experiment processes. Then we propose a method to fit the normalized AMN respect to the kinematic parameters of the cold atomic cloud, and successfully suppress this noise from 0.11 to 0.038 using the fitting result. With this method, we improve the fringe phase resolution from 0.244 rad to 0.092 rad, and reduce the dynamic gravity measurement noise from 2.69 mGal to 1.68 mGal. This study finds and suppresses a key noise source for the dynamic atom gravimeters, which is important for further improving its precision. The proposed method can be also applied for precision enhancement for other dynamic atom interferometer-based sensors, such as the atom gradiometers and gyroscopes.