Assessing the Clock of Gaia: Design and Implementation of A Clock Framework Simulator

Abstract

A powerful and highly configurable simulator of generic clock frameworks is presented and evaluated. This software tool was initially designed to test the reliability of clock data for the Gaia space mission. However, our application has been developed as much parameterized as possible in order to easily adapt it to any other space mission. The main goals of our software tool are to simulate the real performance of an atomic master clock, including the typical noises present in this kind of devices, and to check the reliability of the generation and distribution of clock sub-products. The latter, which are generated by other devices such as frequency multipliers and dividers, are also implemented in the simulator, as well as the corresponding transmission lines. In our simulator the clock outputs obtained from the several nodes of the framework can be displayed with the appropriate graphical tools, therefore easing the task of validating several design issues. Also, the parameters of the master clock and of all the framework devices, as well as the whole clock framework structure are entered using XML files, which can also be graphically verified. Finally, the accuracy and stability of the atomic clock which is expected to fly on-board of Gaia is assessed. We also discuss in depth the several issues regarding the time data products that Gaia will require and we characterize the most important elements.