The major players in underwater oil exploration now have two different technologies for the precision clocks on board their OBNs. These are chip scale atomic clocks (CSAC) and precision clocks based on ultra-low consumption OCXOs. These clocks must meet three key parameters, namely GPS synchronization accuracy (up to 1 nanosecond), the ability to maintain the precise time over several weeks to several months (1 to 5ms), and lastly the lowest possible energy consumption (less than 150 mW at 5°C). Usually, for the longest missions (>90 days), it is common to see CSACs used as reference clocks.
This is where they are most relevant but their prohibitive cost and low availability on the market make them less attractive. Increasingly, users of CSACs are turning to alternative and less expensive solutions that are more available for a certain part of their OBN catalogue. These are high-precision clocks based on ovenized controlled quartz oscillators. The Covid-19 global pandemic and the fall of the oil markets and worldwide demand are causing an unprecedented crisis in our sector. However, the crisis is only accelerating a movement already started in 2018 and in acceleration since 2019. It consists in using more and more OCXOs for increasingly longer missions.
This is made possible thanks to the technological progress of OCXOs, with boosted performances thanks to deep learning and predictive algorithms. This article aims to present the latest technological advances for high-precision clocks based on ovenized quartz oscillators. The conclusions of this study will help users to choose the right OCXO technology according to their targets of performance and unit cost per OBN.
