Recent developments in time & frequency dissemination systems

The paper addresses the activities performed on a novel time & frequency dissemination (T&F D) system based on ESA Patent 407, including its most recent developments. The method allows to transfer the precision and the stability features of a state-of-the-art ground clock to a less performant clock module on board a satellite. By implementing the patent methodology, the on board clock module becomes the "master time & frequency dissemination source" for all the ground terminals located in the footprint of the satellite hosting the on board clock module. The paper, after having addressed the basic principles of the method, provides a summary description of the time & frequency dissemination system, giving an overview of the applications that can benefit of it and comparing its performances against the ones of the main competing systems. The actions for the definition of the system and for assessing the related performances are described as well. The final part of the paper is dedicated to the description of the most recent activity, consisting in the realisation of the experimental setup and in the performance of a field trial campaign for the assessment of the actual system performances. The paper is concluded by highlighting future planned activities following the field trial campaign.