The impact and resolution of the GPS week number rollover of April 2019 on autonomous geophysical instrument platforms

• Published in: Geoscientific Instrumentation, Methods and Data Systems
• Main Authors: Coyle, Shane, Clauer, C. Robert, Hartinger, Michael D., Xu, Zhonghua, Peng, Yuxiang
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10919/109578; https://doi.org/10.5194/gi-10-161-2021

Instrument platforms the world over often rely on GPS or similar satellite constellations for accurate timekeeping and synchronization. This reliance can create problems when the timekeeping counter aboard a satellite overflows and begins a new epoch. Due to the rarity of these events (19.6 years for GPS), software designers may be unaware of such circumstance or may choose to ignore it for development complexity considerations. Although it is impossible to predict every fault that may occur in a complicated system, there are a few "best practices" that can allow for graceful fault recovery and restorative action. These guiding principles are especially pertinent for instrument platforms operating in space or in remote locations like Antarctica, where restorative maintenance is both difficult and expensive. In this work, we describe how these principles apply to a communications failure on autonomous adaptive low-power instrument platforms (AAL-PIP) deployed in Antarctica. In particular, we describe how code execution patterns were subtly altered after the GPS week number rollover of April 2019, how this led to Iridium satellite communications and data collection failures, and how communications and data collection were ultimately restored. Finally, we offer some core tenets of instrument platform design as guidance for future development. Office of Polar ProgramsNational Science Foundation (NSF)NSF - Directorate for Geosciences (GEO) [1543364]; Division of Atmospheric and Geospace SciencesNational Science Foundation (NSF)NSF - Directorate for Geosciences (GEO) [2027210, 2027168] Published version This research has been supported by the Office of Polar Programs (grant no. 1543364) and the Division of Atmospheric and Geospace Sciences (grant nos. 2027210 and 2027168).