ESA’s JUICE End-to-End Orbit Determination Simulation to Calibrate On-Board Accelerometer

Abstract

The purpose of this work is to determine an in-flight calibration procedure for JUICE’s on-board accelerometer. Its measurements will be combined with the range and range-rate observables by 3GM gravity experiment to estimate the Callisto’s gravity field, during its eleven flybys. The 3GM experiment needs a precise orbit determination to fulfill its scientific goals, but propellant sloshing would affect this precision. In order to improve the physical model implemented in the OD software, it is necessary to measure these disturbances using an accelerometer. The accelerometer’s measurement error model is composed of a random noise, a bias, a bias rate and a scale factor. This investigation shows that the scale factor does not affect the estimation of Callisto’s spherical harmonic coefficients in a significant way. On the other hand, the estimation of bias and bias rate parameters is a difficult process because of their strong correlation. This work demonstrates that the 3GM scientific goals can be achieved, but high caution on JUICE’s accelerometer design is necessary. In order to overcome these difficulties, an in-flight calibration strategy is proposed.