Gaia Data Release 2 Calibration and mitigation of electronic offset effects in the data
Gaia Data Release 2 Calibration and mitigation of electronic offset effects in the data
复制标题
盖亚数据第 2 版 数据中电子偏移效应的校准和缓解
DOI：
10.1051/0004-6361/201832716
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发表时间：
2018
影响因子：
6.5
通讯作者：
Hambly N
中科院分区：
文献类型：
--
作者：
Hambly N
欧洲航天局的Gaiasatellite于2013年12月发射到L2轨道。这项雄心勃勃的使命对仪器修正产生的残余系统误差有严格的要求，以满足亚10微弧秒天体测量的设计目标。在科学仪器的设计和建造阶段，详细研究了各种关键校准，以确保在轨道上实现这一目标。特别是，它被确定为模拟-数字转换电子设备的模拟侧的视频链偏移表现出的不稳定性，不能完全减轻通过修改飞行hardware.AimsWe提供了一个详细的描述的行为的电子偏移水平短（<1毫秒）的时间尺度，确定各种系统的影响，被统称为“偏移非均匀性”。的影响表现为瞬态扰动的毛零点电子偏移水平，定期监测的一部分，整体calibrationprocess.MethodsUsing在轨道上的特殊校准序列沿着与简单的参数模型，我们展示了如何可以校准的效果，以及如何将这些校准应用到科学数据。虽然该过程的校准部分相对简单，在科学数据处理过程中的校准的应用程序需要一个详细的在地面上重建的读出定时的每个电荷耦合器件（CCD）的每个设备上的样本，以正确地预测高度依赖于时间的性质的校正。结论我们证明了所有CCD和操作仪器/模式板上Gaia的视频链噪声限制的性能恢复在绝大多数的科学样本。
ContextThe European Space Agency’sGaiasatellite was launched into orbit around L2 in December 2013. This ambitious mission has strict requirements on residual systematic errors resulting from instrumental corrections in order to meet a design goal of sub-10 microarcsecond astrometry. During the design and build phase of the science instruments, various critical calibrations were studied in detail to ensure that this goal could be met in orbit. In particular, it was determined that the video-chain offsets on the analogue side of the analogue-to-digital conversion electronics exhibited instabilities that could not be mitigated fully by modifications to the flight hardware.AimsWe provide a detailed description of the behaviour of the electronic offset levels on short (<1 ms) timescales, identifying various systematic effects that are known collectively as “offset non-uniformities”. The effects manifest themselves as transient perturbations on the gross zero-point electronic offset level that is routinely monitored as part of the overall calibration process.MethodsUsing in-orbit special calibration sequences along with simple parametric models, we show how the effects can be calibrated, and how these calibrations are applied to the science data. While the calibration part of the process is relatively straightforward, the application of the calibrations during science data processing requires a detailed on-ground reconstruction of the readout timing of each charge-coupled device (CCD) sample on each device in order to predict correctly the highly time-dependent nature of the corrections.ResultsWe demonstrate the effectiveness of our offset non-uniformity models in mitigating the effects inGaiadata.ConclusionsWe demonstrate for all CCDs and operating instrument/modes on boardGaiathat the video-chain noise-limited performance is recovered in the vast majority of science samples.