A novel approach to reduce environmental noise in microgravity measurements using a Scintrex CG5
A novel approach to reduce environmental noise in microgravity measurements using a Scintrex CG5
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DOI：
10.1016/j.jappgeo.2018.03.022
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发表时间：
2018-05-01
影响因子：
2
通讯作者：
Chapman, David
中科院分区：
文献类型：
--
作者：
Boddice, Daniel;Atkins, Phillip;Chapman, David
用于测量目的的微重力测量的准确性和可重复性受到两个主要噪声源的影响：传感器和电子设备产生的仪器噪声，以及人类活动、风、微震活动和其他振动噪声源产生的环境噪声源。文献中关于这些不同噪声源的定量值及其对微重力测量的意义的信息很少。进行了实验，用多种仪器对这些噪声源进行量化，并制定减少这些不需要的信号的方法，从而提高微重力测量的准确性或速度。外部环境噪声源被发现集中在较高的频率（> 0.1 Hz），在仪器的带宽内。相反，内部仪器噪声在远低于最大积分时间的倒数的频率处占主导地位，并且被确定为当前仪器的限制因素。最佳的时间为120和150秒之间的集成被认为是测试的仪器。为了减少外部环境噪声对微重力测量的影响，一个过滤和despiking技术创建使用的数据从嘈杂的环境旁边的主要道路和外面的大风天。该技术在测量的可重复性方面有了显著的改善，在许多不同的数据集上获得了40%到50%的低标准偏差，然后在野外条件下使用已知大小的异常对过滤技术进行了测试，并对不同过滤方法进行了比较。结果表明，改进与所提出的方法比传统的，或boxcar，平均过程中表现更好。建议的削峰过程通常被认为是无效的，当完整的测量记录被丢弃时，获得更大的增益。现场勘测结果比静态测量结果更差，可能是由于在勘测期间移动Scintrex的动作导致传感器不稳定和弹性松弛，或液体倾斜传感器产生额外的低频仪器噪声。然而，该技术将大大提高准确性，减少测量时间，无论是在静态测量方面，例如在参考站点和观测站，还是在实地测量方面，都将使用基于新技术的下一代仪器，例如原子干涉测量法，从而节省时间和费用。(C)2017年，作者。由爱思唯尔公司出版
The accuracy and repeatability of microgravity measurements for surveying purposes are affected by two main sources of noise; instrument noise from the sensor and electronics, and environmental sources of noise from anthropogenic activity, wind, microseismic activity and other sources of vibrational noise. There is little information in the literature on the quantitative values of these different noise sources and their significance for microgravity measurements. Experiments were conducted to quantify these sources of noise with multiple instruments, and to develop methodologies to reduce these unwanted signals thereby improving the accuracy or speed of microgravity measurements. External environmental sources of noise were found to be concentrated at higher frequencies (> 0.1 Hz), well within the instrument's bandwidth. In contrast, the internal instrumental noise was dominant at frequencies much lower than the reciprocal of the maximum integration time, and was identified as the limiting factor for current instruments. The optimum time for integration was found to be between 120 and 150 s for the instruments tested.In order to reduce the effects of external environmental noise on microgravity measurements, a filtering and despiking technique was created using data from noisy environments next to a main road and outside on a windy day. The technique showed a significant improvement in the repeatability of measurements, with between 40% and 50% lower standard deviations being obtained over numerous different data sets.The filtering technique was then tested in field conditions by using an anomaly of known size, and a comparison made between different filtering methods. Results showed improvements with the proposed method performing better than a conventional, or boxcar, averaging process. The proposed despiking process was generally found to be ineffective, with greater gains obtained when complete measurement records were discarded. Field survey results were worse than static measurement results, possibly due to the actions of moving the Scintrex during the survey which caused instability and elastic relaxation in the sensor, or the liquid tilt sensors, which generated additional low frequency instrument noise. However, the technique will result in significant improvements to accuracy and a reduction of measurement time, both for static measurements, for example at reference sites and observatories, and for field measurements using the next generation of instruments based on new technology, such as atom interferometry, resulting in time and cost savings. (C) 2017 The Authors. Published by Elsevier B.V.