Design procedure of a highly stable GPS disciplined BVA OCXO for the MeerKAT telescope Time and Frequency System.

The MeerKAT telescope Time and Frequency System (TFS) clock ensemble consists of two hydrogen Microwave Amplification by Stimulated Emission of Radiation (MASER) units. The system requires a clock monitoring system that can detect degraded clock performance over short timescales. Individual clock variance can be calculated by using the three-cornered hat technique, however this would require a third clock. This paper presents work completed on using a highly stable Boîtier à Vieillissement Amélioré (BVA) Oven Controlled Crystal Oscillator (OCXO) as a third clock for measuring individual clock stability over short timescales. Clock performance is measured using Dual-Mixer Time Difference (DMTD) analysers. The long-term stability of the BVA OCXO is kept close to that of the MASER by steering it to Global Positioning System (GPS) using the dual frequency GPS receiver over long timescales. The results show that a frequency stability of 2e-13 at 1 second can be achieved when steering the BVA OCXO with a constant control voltage. Thus the three corner hat technique would be able to detect a frequency stability degradation of the two Hydrogen MASERs that is higher than the results shown. Different controller topologies are presented and their performance compared.