Effective measurement height of atom gravimeters

TL;DR

This paper determines the effective measurement heights of atom gravimeters using LTI system theory, enabling more accurate gravity measurements by accounting for the instrument's measurement height.

Contribution

It introduces a method to calculate the effective measurement height as a simple fraction of the total trajectory, improving gravity measurement accuracy.

Findings

Effective measurement heights are expressed as simple fractions of the total trajectory.

Using the effective measurement height reduces gravity gradient uncertainties.

The method eliminates up to 1 μGal of uncertainty from gravity gradient effects.

Abstract

The effective measurement heights of the fountain and the release types of atom gravimeters have been determined using the description of the instruments as linear time-invariant (LTI) system. The distance from the initial position of the atoms to the locus of the effective measurement height is expressed as simple fraction of the total trajectory length. Leaving the measured gravity for reporting at the effective measurement height allows to eliminate the gradient from calculations and avoid up to 1 $\mu$Gal of its uncertainty added to the instrument error budget.