Analysis of the Dick Effect for AI-based Dynamic Gravimeter

TL;DR

This paper investigates the impact of dead time in classical accelerometers on AI-based dynamic gravimeters, deriving formulas to understand and mitigate measurement noise caused by high-frequency aliasing.

Contribution

It introduces a frequency domain formula for gravity measurement noise due to dead time, offering strategies to reduce noise in AI-based gravimeters.

Findings

A dead time of 0.12 s causes 8 mGal noise

High-frequency aliasing is identified as the noise source

Reducing dead time and high-frequency noise mitigates measurement errors

Abstract

Atom interferometer (AI)-based dynamic gravimeter enable high-precision absolute gravity measurements, crucial for applications in geophysics, navigation, resource exploration, and metrology. Understanding their underlying mechanisms and minimizing measurement noise are essential for enhancing performance. This work investigates the gravity measurement noise in AI-based systems induced by the dead time of the classical accelerometer. Using actual dynamic gravity measurement data, we demonstrate that a dead time of 0.12 s introduces significant gravity measurement noise of 8 mGal. To elucidate the mechanism of this noise, we derive a formula for this noise in frequency domain, identifying high-frequency aliasing as its source. Analysis of the derived expressions indicates that reducing the dead time duration and suppressing the high-frequency noise of the acceleration are effective strategies for mitigating this noise. This work provides significant insights for noise analysis and future scheme design of AI-based dynamic gravimeters.