The impact and resolution of the GPS week number rollover of April 2019 on autonomous geophysical instrument platforms
The impact and resolution of the GPS week number rollover of April 2019 on autonomous geophysical instrument platforms
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DOI：
10.5194/gi-10-161-2021
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发表时间：
2021-07
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影响因子：
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通讯作者：
S. Coyle;C. Clauer;M. Hartinger;Zhonghua Xu;Yuxiang Peng
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作者：
S. Coyle;C. Clauer;M. Hartinger;Zhonghua Xu;Yuxiang Peng
摘要。世界各地的仪器平台通常依靠GPS或类似的卫星星座来精确计时和同步。当卫星上的计时计数器溢出并开始一个新的纪元时，这种依赖就会产生问题。由于这些事件的罕见性（GPS为19.6年），软件设计人员可能不知道这种情况，或者出于开发复杂性的考虑而选择忽略它。尽管不可能预测复杂系统中可能发生的每一个故障，但是有一些“最佳实践”可以允许优雅的故障恢复和恢复操作。这些指导原则特别适用于在空间或南极洲等偏远地区运行的仪器平台，在这些地方，恢复性维护既困难又昂贵。在这项工作中，我们描述了这些原则如何应用于部署在南极洲的自主自适应低功耗仪器平台（AAL-PIP）的通信故障。特别是，我们描述了2019年4月GPS周数轮转后代码执行模式如何发生微妙变化，这如何导致铱星通信和数据收集失败，以及通信和数据收集最终如何恢复。最后，提出了仪器平台设计的一些核心原则，为今后的发展提供指导。
Abstract. 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.