Atom Strapdown: High Rate Phase Shift Calculation for Atom Interferometer Inertial Sensors

Abstract

In this paper, an alternative technique to estimate the response of a cold atom interferometer (CAI) is presented. Using data of a conventional inertial measurement unit and the common strapdown terminology, the position of the atom wave packet is tracked in a newly introduced sensor frame. This enables a hybridisation of both systems. The sensor frame allows for an easier mathematical description of the interferometer measurement and makes integration into higher-level navigation systems possible. Equations for a hybrid IMU/CAI system with several arbitrarily placed sensor frames are stated, as well as a compressed Multi-Axis model, following current developments in chip scale atom interferometry. The atom strapdown is compared with another common hybridisation technique which utilizes convolution of accelerometer data with the interferometer response function. The comparison is supported by real data. The dynamic terms resulting from the transformation of the IMU frame into the sensor frame of the CAI are evaluated in simulations and further discussed. Finally, the implications of the findings for future hybrid quantum navigation systems are stated.