A Precise Disciplined Boîtier à Vieillissement Amélioré Oven Controlled Crystal Oscillator for a Radio Telescope Observatory

This paper presents the development and performance evaluation of a Global Navigation Satellite System (GNSS)-disciplined Boîtier à Vieillissement Amélioré (BVA) Oven Controlled Crystal Oscillator (OCXO), which functions as the third clock in the MeerKAT telescope’s clock ensemble. By utilizing the three-cornered hat method, the stability of each individual Microwave Amplification by Stimulated Emission of Radiation (MASER) unit can be assessed, enabling the detection of short-term frequency degradation. The BVA OCXO frequency is adjusted by locking a dual-frequency GNSS receiver clock to the BVA OCXO. With the Fugro AtomiChron real-time precise time service, a dedicated timescale is provided within Precise Point Positioning (PPP) solutions. A single-board computer processes Septentrio Binary Format (SBF) data from the receiver, and the clock bias is steered to zero using a Proportional-Integral (PI) controller, allowing the BVA OCXO frequency to converge within ±100 ps of timescale in seconds, although initial PPP convergence requires several hours. System stability was assessed using a Dual-Mixer Time Difference (DMTD) analyzer, with the MASER as the reference. The results show that the system performs better than leading cesium standards, with an Allan Deviation of 1.5 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−13</sup> at τ = 1 second and 4.4 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−15</sup> at τ = 100,000 seconds, demonstrating the system's robustness and suitability for precision timing applications.