Tensor gravity gradiometry with a single-axis atom gradiometer

TL;DR

This paper introduces a novel method using a single-axis atom interferometric gravity gradiometer to measure off-diagonal gravity gradient tensor components by tilting the device, enabling more comprehensive gravitational surveys with minimal sensitivity loss.

Contribution

The paper presents a new technique for inferring off-diagonal gravity gradient tensor components with a single-axis atom interferometer through tilting and dynamic platform adjustments.

Findings

The method accurately measures off-diagonal tensor components.

Sensitivity to vertical gradients is maintained with tilting.

Optical-gimbal techniques mitigate errors on dynamic platforms.

Abstract

We propose a method for using a single-axis atom interferometric gravity gradiometer to measure off-diagonal elements of the gravity gradient tensor. By tilting the gradiometer, the measured gradient becomes a linear combination of different components of the gravity gradient tensor, and through multiple measurements at different tilts the separate tensor components can be inferred. We present a theoretical and numerical investigation of this technique, both for terrestrial surveys where the tilt is statically set by the user and for surveys where a strapdown sensor is dynamically tilted by the motion of the platform. We show that the gradiometer's sensitivity to the vertical gravity gradient is only slightly reduced by this method while allowing for more gradiometer information to be obtained. Major sources of error and loss of sensitivity on dynamic platforms are shown to be mitigated using an optical-gimbal technique employing commercially-available fibre-optic gyroscopes and tip-tilt mirrors.