Geist Jon, Gaitan Michael
National Institute of Standards and Technology, Gaithersburg, MD 20899 USA.
J Res Natl Inst Stand Technol. 2022 Jan 22;126:126038. doi: 10.6028/jres.126.038. eCollection 2021.
We simulated the effects of gimbal-alignment errors and rotational step-size errors on measurements of the sensitivity matrix and intrinsic properties of a triaxial accelerometer. We restricted the study to measurements carried out on a two-axis calibration system using a previously described measurement and analysis protocol. As well as imperfections in the calibration system, we simulated imperfect orthogonality of the accelerometer axes and non-identical sensitivity of the individual accelerometers in an otherwise perfect triaxial accelerometer, but we left characterization of other accelerometer imperfections such as non-linearity for future study. Within this framework, sensitivity-matrix errors are caused by imperfections in the construction and installation of the accelerometer calibration system, but not by the accelerometer imperfections included in the simulations. We use the results of this study to assign type B uncertainties to the components of the sensitivity matrix and related intrinsic properties due to imperfections in the measurement system. For calibrations using a reasonably well manufactured and installed multi-axis rotation stage such as that studied in this paper, we estimated upper bounds to the standard uncertainties of the order of 1×10-5, 2×10-5, 5×10-5, and 2×10-4 for the intrinsic sensitivities, diagonal elements of the sensitivity matrix, off-diagonal elements of the sensitivity matrix, and zero-acceleration offsets, relative to a sensitivity-matrix element of 1, respectively, and 5×10-3 degrees for the intrinsic angles.
我们模拟了万向节对准误差和旋转步长误差对三轴加速度计灵敏度矩阵测量及固有特性的影响。我们将研究限制在使用先前描述的测量和分析协议在双轴校准系统上进行的测量。除了校准系统中的缺陷外，我们还模拟了加速度计各轴不完全正交以及在其他方面完美的三轴加速度计中各个加速度计灵敏度不相同的情况，但我们将其他加速度计缺陷（如非线性）的表征留待未来研究。在此框架内，灵敏度矩阵误差是由加速度计校准系统的构建和安装缺陷引起的，而非模拟中包含的加速度计缺陷。我们利用本研究结果，因测量系统缺陷为灵敏度矩阵的各分量及相关固有特性赋予B类不确定度。对于使用如本文所研究的制造和安装合理良好的多轴旋转台进行的校准，我们估计相对于灵敏度矩阵元素为1时，固有灵敏度、灵敏度矩阵对角元素、灵敏度矩阵非对角元素和零加速度偏移的标准不确定度上限分别约为1×10⁻⁵、2×10⁻⁵、5×10⁻⁵和2×10⁻⁴，固有角度的标准不确定度上限为5×10⁻³度。
