TOWARDS HYBRID INERTIAL NAVIGATION BASED ON ATOM INTERFEROMETRY FOR SPACE APPLICATIONS

Abstract

Inertial sensors, which often employ a mass-spring system, typically perform a relative measurement of the local acceleration field and therefore require calibration to establish scale and to remove offset bias. However, these parameters are not stable and eventually drift leading to errors in navigation systems. This is particularly problematic for the offset bias since it will generate a positioning error which grows quadratic in time. Inertial sensing by atom interferometry in contrast, yields an absolute measurement of the local acceleration field which eliminates the offset bias. Despite these advantages, atom interferometer-based inertial sensors have two major drawbacks, namely the low sample rate (in the order of some Hz) and the limited dynamic range, leading to phase wrapping and an ambiguous measurement output. The combination of an atom interferometer with a opto-mechanical sensors is a promising approach to overcome the beforementioned problems. We are planning to combine an atom interferometer based on stimulated Raman transitions in a Mach-Zehnder configuration using Rubidium-87 with opto-mechanical sensors. The atom interferometer shall be capable measuring the linear acceleration sequentially along three independent axes. The opto-mechanical sensors will be directly attached to the retro-reflectors of the atom interferometer and built by cavities that are read out by optical means through a common laser system also utilized for the atom interferometer. Our work focusses on the technology maturation and miniaturization of the system with the final goal to utilizes such a sensor in space on a satellite. Therefore, a first prototype is under development for terrestrial use. Moreover, we are planning to launch such a sensor system onboard a TEXUS (Technology experiments under zero gravity) rocket within the next five years, pathing the way for a CubeSat mission in the next eight years and a technology demonstration on a satellite within the next eleven years. This talk gives an overview on mission specific requirements for the different use cases and the top level size, weight and power budgets as well as the current status of these activities