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Photis Patonis Petros Patias Ilias N. Tziavos Dimitrios Rossikopoulos 《地球空间信息科学学报》2018,21(2):139-148
This paper presents a methodology and its software implementation for the performance evaluation of low-cost accelerometer and magnetometer sensors for use in geomatics applications. A known mathematical calibration model has been adopted. The method was completed with statistical methodologies for adjusting observations and has been extended to calculate accuracies for the attitude, heading, and tilt angles estimation that are of interest to geomatics applications. The evaluation method consists of two stages. First, the evaluation method reviews the total magnitude of acceleration or the strength of the magnetic field. Second, the evaluation is more detailed and concerns the determination of mathematical parameters that describe both accelerometer and magnetometer working model. A software tool that implements the evaluation model has been developed and is applied both in accelerometer and magnetometer measurement data-sets acquired from a low-cost sensor system. 相似文献
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Mário Pereira Fernando Veloso-Gomes José Lima Sérgio Oliveira 《Marine Georesources & Geotechnology》2016,34(7):617-629
This article describes the implementation of a monitoring system on the breakwater at the Funchal Port (Madeira Island, Portugal) for the purpose of understanding its dynamic behavior and the temporal evolution of structural health. The monitoring system focuses on the breakwater superstructure and aims to identify the evolution of damage on the breakwater and analyze the impact of cruise ships docking and undocking. The system includes the measurement of displacements through geodetic techniques using global navigation satellite systems and the measurement of vibrations using accelerometers. Ten observation campaigns were performed over almost 3 years. As the measured displacements during this period were less than 7.5 mm it can be concluded that, despite some visible cracks, the breakwater superstructure did not suffer significant structural changes. It was shown from the measured acceleration records that some of the main modal parameters could be identified, namely the main natural frequencies of the superstructure. Through an analysis of the natural frequencies progression over time, it will be possible to identify deterioration effects on the foundation and/or the superstructure. The comparison of natural frequencies identified could be useful to evaluate the impact of these events on structural health. 相似文献
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根据台站场地条件进行地震动参数校正,有助于提高地震预警的有效性和准确性。针对我国地震预警台网中部分台址场地条件信息不完整及观测仪器的多样性,通过采用不同灵敏度的力平衡式加速度仪、速度仪和MEMS烈度仪,同时进行大量不同类别场地的地脉动观测,多角度对比分析时、频差别,探讨基于地震预警仪观测地脉动评价场地条件的可行性。结果表明,加速度仪灵敏度越高,H/V谱比卓越频率越易识别;速度仪与力平衡式加速度仪观测的地脉动,三分向傅氏谱和H/V谱比的谱形与卓越频率均一致;与TAG-33M强震仪相比,TMA-53烈度仪观测的地脉动整体幅值略高,波形较差,但随着振幅增大趋于一致;在近80%的场地上,TAG-33M强震仪与TMA-53烈度仪观测的地脉动傅氏谱卓越频率相差＜0.5 Hz;当幅值均方根值＞0.05 Gal时,TAG-33M强震仪与TMA-53烈度仪观测的地脉动竖向和水平向傅氏谱均趋于一致;当幅值均方根值为0.02 Gal～0.05 Gal时,TAG-33M强震仪与TMA-53烈度仪观测的地脉动竖向和水平向傅氏谱谱形均有较高的相似性;当幅值均方根值＜0.02 Gal时,TAG-33M强震仪与TMA-53烈度仪观测的地脉动傅氏谱谱形相差较大,相似性低;依据TAG-33M强震仪观测地脉动H/V谱比的卓越频率判定场地类别,准确率达83.3%;TMA-53烈度仪观测地脉动的H/V谱比过于平坦,大多数场地上卓越频率识别困难。 相似文献
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A. Bezděk 《Studia Geophysica et Geodaetica》2007,51(3):461-468
For analyzing measurements of any kind, it is important to estimate the probability distribution of the measurement errors.
When modelling the observations using least-squares fitting, the distribution of the errors plays a vital role in choosing
the merit function to be minimized, as unnormally distributed errors (e.g. outliers, or displaying asymmetry around the mean)
may substantially skew a least-squares fit of estimated model parameters. Using the CACTUS accelerometer data covering heights
of 230–750 km, we will show that the statistical relationship between the commonly used semi-empirical models of neutral thermospheric
density (MSIS, DTM) and the observed densities is consistent with lognormal distribution, i.e. the logarithm of the ratio
of the measurements to the predictions is approximately normally distributed. This experimental fact may be applied in modelling
the neutral thermospheric density.
bezdek@asu.cas.cz 相似文献
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强震动观测仪器面临的机遇和挑战 总被引：1，自引：1，他引：0
本文介绍了国内外强震仪、力平衡加速度计、烈度计、MEMS加速度仪等强震动观测仪器的发展历史与现状，概述了强震动记录中典型异常波形产生的原因和力平衡加速度计的仪器响应误差及校正，建议了解决强震仪器缺陷的措施，分析了强震仪在强震动观测发展中面临的机遇和挑战。研究结果如下:① 进行强震动记录异常波形的研究是有针对性改进现有强震仪存在问题的很好途径；② 早期数字强震仪（力平衡加速度计频带范围0至30Hz）获取的强震动记录应进行仪器校正；③ 应跟踪强震动观测新方法和相关领域新技术，发展MEMS加速度仪和光纤加速度仪等新型仪器。 相似文献
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Anibal Ojeda Samuel Martinez Maria Bermudez Kuvvet Atakan 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):791-797
The new accelerographic network of Santa Fe de Bogotá is composed of 29 three-component stations with sensors at the surface and three additional six-component borehole stations with three sensors at the surface and three at depth (115, 126 and 184 m). In total, 32 stations have been operative in the metropolitan area of Bogotá since 1999. During this period of time, a significant number of weak motion are recorded and used for a preliminary analysis of local site effects. Using the SH-wave response spectra we verify the behavior of the different seismic zones proposed by the previous microzonation study of the city. A comparison between normalized SH-wave response spectra and the normalized design spectra for each zone clearly depicts that parts of the design spectra should be revised, as well as the boundaries between different zones may require some changes. The spectral amplification levels reach up to a factor of 5. The predominant periods obtained by the amplification spectra in different stations in the city, show variability from 0.3 to 3.0 s. A comparison is also made between the predominant periods obtained using H/V spectral ratios of microtremors and those using weak motion. In general, microtremors tend to predict slightly lower values of dominant periods than those calculated by the weak motion spectra. However, there is a general correlation between the two data sets. Using the data recorded by one of the borehole station, an equivalent linear seismic response analysis was conducted. The modeled and recorded response spectra show similarities in period peaks, however, the modeled soil amplification is underestimated for periods less than 0.8 s. Since the available record is weak motion which represents mostly the linear response of the soils, further analysis is required. 相似文献
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