Cold Atom Interferometry for Gravimetry in Dynamic Environments

We have constructed a robust and portable quantum gravimeter that has carried out measurements at sea without a gimbal. While highly sensitive atom-based gravimeters have been demonstrated in the lab, the ability to operate in dynamic environments has proven to be difficult. Our system uses a co-located MEMS cosensor, a high repetition rate (20-30Hz), and passive vibration isolation to maintain fringe visibility even with moderate platform motion. Multiple field tests have demonstrated the ability to measure variations in local gravity while subject to dynamic environments and to maintain accuracy through short periods of more intense vibration (low fringe visibility). The gravimeter was tested at sea and successfully improved an inertial navigation solution over a two-week period via matching to a map of local gravity anomaly. Another set of measurements taken at different heights across a six-story building yielded an accurate measure of Earth's gradient field. Further efforts to identify inaccuracies in the interferometer and improve accuracy and long-term stability of the gravimeter are underway.