Enhancing the precision limits of interferometric satellite geodesy missions

Satellite geodesy uses the measurement of the motion of one or more satellites to infer precise information about the Earth's gravitational field. In this work, we consider the achievable precision limits on such measurements by examining approximate models for the three main noise sources in the measurement process of the current Gravitational Recovery and Climate Experiment (GRACE) Follow-On mission: laser phase noise, accelerometer noise and quantum noise. We show that, through time-delay interferometry, it is possible to remove the laser phase noise from the measurement, allowing for almost three orders of magnitude improvement in the signal-to-noise ratio. Several differential mass satellite formations are presented which can further enhance the signal-to-noise ratio through the removal of accelerometer noise. Finally, techniques from quantum optics have been studied, and found to have great promise for reducing quantum noise in other alternative mission configurations. We model the spectral noise performance using an intuitive 1D model and verify that our proposals have the potential to greatly enhance the performance of near-future satellite geodesy missions.

Automated summary

Satellite geodesy is a technique that uses satellite motion measurements to estimate accurate information about Earth's gravitational field. This study focuses on the precision limits of such measurements by examining approximate models for three main noise sources in the measurement process of the GRACE Follow-On mission: laser phase noise, accelerometer noise, and quantum noise. The study shows that the removal of laser phase noise through time-delay interferometry can significantly improve the signal-to-noise ratio. Furthermore, the use of differential mass satellite formations can further enhance the signal-to-noise ratio by eliminating accelerometer noise. Additionally, the study suggests that techniques from quantum optics can reduce quantum noise in alternative mission configurations. The proposed methods have the potential to greatly enhance the performance of future satellite geodesy missions.