Probing gravitational waves using GNSS constellations

TL;DR

This paper proposes using GNSS satellite constellations with atomic clocks to detect gravitational waves in the unexplored microhertz frequency range by analyzing orbit deviations caused by GW interactions.

Contribution

It introduces a novel framework for detecting gravitational waves through orbit deviations in GNSS constellations, bridging the microhertz frequency gap.

Findings

Resonance amplifies gravitational wave effects on satellite orbits.

Orbital deviations are coherent across the constellation, aiding GW detection.

GNSS data can be used to test general relativity in new frequency regimes.

Abstract

The detection of gravitational waves opened up a new window to look into the Universe by probing phenomena invisible through electromagnetic observations. As gravitational waves interact very weakly with matter, their detection is challenging and expensive. So far, they have been observed in the nHz frequency and audible ranges. Future detectors are expected to cover the mHz frequency, leaving the $\mu$Hz regime largely unexplored. With on-board atomic clocks and orbits determined to the cm, Global Navigation Satellite System constellations (GNSS), like GPS or Galileo, offer free access to more than 30 years of clock and orbit data for tests of general relativity. We develop a framework for calculating the deviation in the evolution of GNSS orbits induced by gravitational wave signals. We show that when a gravitational wave interacts in resonance with a satellite's orbit, effects amplify, which can be used to bridge the gap in the $\mu$Hz regime. Finally, we demonstrate that the orbital deviations induced by gravitational waves are coherent across the entire constellation, enabling a satellite network to disentangle GW effects from satellite systematics.