arXiv subjects

V. D. Nagornyi

Publications and source records attributed to V. D. Nagornyi.

3 recordsLinked to original sources

arXiv2015

Improving absolute gravity estimates by the $L_p$-norm approximation of the ballistic trajectory

Iteratively Re-weighted Least Squares (IRLS) were used to simulate the $L_p$-norm approximation of the ballistic trajectory in absolute gravimeters. Two iterations of the IRLS delivered sufficient accuracy of the approximation without a significant bias. The simulations were performed on different samplings and perturbations of the trajectory. For the platykurtic distributions of the perturbations, the $L_p$-approximation with $3<p<4$ was found to yield several times more precise gravity estimates compared to the standard least-squares. The simulation results were confirmed by processing real gravity observations performed at the excessive noise conditions.

physics.ins-det↗

arXiv2012

Response functions of atom gravimeters

Atom gravimeters are equivalent to non-multi-level corner-cube gravimeters in translating the gravity signal into the measurement result. This enables description of atom gravimeters as LTI systems. The system's impulse responses by acceleration, velocity, and displacement are found to have the shape of triangle, meander, and the Dirac comb resp. The effects of inhomogeneous gravity field are studied for constant and linear vertical gradients and self-attraction of the instrument. For the constant gradient the effective measurement height is below the top of the trajectory at 1/6 and 7/24 of its length for the fountain and the release types of the instruments resp. The analysis is expanded to the gravimeters implementing the Bloch oscillations at the apex of the trajectory. In filtering the vibrations these instruments are equivalent to the first-order low-pass filters, while other atom gravimeters are equivalent to the second-order low-pass filters.

physics.ins-det↗

arXiv2012

Effective measurement height of atom gravimeters

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 $μ$Gal of its uncertainty added to the instrument error budget.

physics.ins-det↗