IEEE Trans Ultrason Ferroelectr Freq Control. 2018 Jun;65(6):911-918. doi: 10.1109/TUFFC.2018.2792779.
Rubidium clocks are currently the most common atomic clocks for space applications, playing a fundamental role in global navigation satellite systems. Their stability is affected by the light-shift effect, turning lamplight variations into frequency variations, e.g., lamplight intensity jumps into frequency jumps. In our previous work, analyzing data from GPS rubidium clocks, we uncovered the impact of the lamp on the in-orbit clock's performance. Specifically, the rubidium clock's random walk of frequency seems to be driven by a compound Poisson process associated with lamplight intensity jumps. Most important, large lamplight-induced frequency jumps could affect the validity of the navigation message. Here, we propose and test on simulated data, a software compensation scheme for lamplight-induced rubidium clock frequency jumps. We show how this could be implemented as an automated onboard process, and the potential improvements this scheme might yield in timekeeping and navigation performance. In particular, we demonstrate the possibility to correct large lamplight-induced frequency jumps in a time smaller than the interval between consecutive navigation message upgrades, thus improving the quality of the navigation message.
铷原子钟是目前空间应用中最常见的原子钟，在全球导航卫星系统中发挥着重要作用。它们的稳定性受到光频移效应的影响，将灯光变化转化为频率变化，例如灯光强度跳跃转化为频率跳跃。在我们之前的工作中，通过分析 GPS 铷原子钟的数据，我们揭示了灯光对在轨时钟性能的影响。具体来说，铷钟的频率随机游走似乎是由与灯光强度跳跃相关的复合泊松过程驱动的。最重要的是，大的灯光引起的频率跳跃可能会影响导航消息的有效性。在这里，我们提出并在模拟数据上进行了测试，一种针对灯光引起的铷原子钟频率跳跃的软件补偿方案。我们展示了如何将其实现为一种自动的机载过程，以及该方案在计时和导航性能方面可能带来的改进。特别是，我们证明了在小于连续导航消息升级之间的间隔的时间内纠正大的灯光引起的频率跳跃的可能性，从而提高导航消息的质量。
