地震计台站标定技术研究
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摘要
地震计是非常关键的地震观测设备,它的性能指标直接影响着地震数据产出的质量,它的参数是进行地震波形反演、地震震级确定的基本资料。而由于各种各样的原因,随着时间的推移和环境条件的变化,地震计的各项性能参数可能会有所变化,因此,一台地震计无论交付使用前,还是在台站使用的过程中,都需要进行标定。
本文对地震计台站标定方法进行了研究,包括以下三个方面:阶跃标定、正弦标定和对比测试地震计灵敏度。这三种标定方法都是用来测量地震计的传递函数的。
阶跃标定被用来测量地震计传递函数低频段的特性。原有阶跃标定数据处理算法在进行数据处理的时候需要人机交互。而且,计算结果的稳定性不高。因此,新的阶跃标定数据处理算法主要解决了两个方面的问题--数据的自动处理和计算结果的稳定性。新算法的整个数据处理过程不需要人的参与。计算机可以完全代替人完成日常标定数据的处理工作。数据处理结果具有很小的离散性。经过实验,对一台BBVS-60地震计多次标定所得结果的最大相对偏差是0.03%。
正弦标定被用来测量地震计全频带的传递函数的特性。原有的正弦标定数据处理算法在进行数据处理的时候也需要人机交互。新的正弦标定数据处理程序同样提高了数据处理的自动化程度,对高频和低频波形采用了两种不同的识别方法,能够有效的自动拾取待测波形,实现了计算机自动处理;对于失真的高频数据还能够进行恢复,提高测量精度。
无论是正弦标定还是阶跃标定都只能给出地震计的“相对灵敏度”,而要计算地震计的“绝对灵敏度”就要采用对比测试的方法。本文介绍了对比测试的实验方法和数据处理算法,并通过对地震计输入的功率谱、地震计自身噪音的功率谱和信噪比的分析,说明了噪音对计算结果稳定性的影响。
本文第一章将介绍论文的背景意义。第二章将分别针对阶跃标定、正弦标定和对比测试法,介绍每种测试方法的基本原理、现存问题以及针对问题提出的解决方案。第三章将介绍如何用信号处理和数值分析的方法具体实现解决方案。第四章将列举算法测试的实验结果并对结果进行分析。第五章为全文总结。
本文介绍的正弦标定和阶跃标定算法已经被应用在“中国数字地震观测网络项目”的“标定软件分项”中,并在全国范围内试运行。对比测试灵敏度算法也用Matlab脚本语言实现,并在地震观测实验室中应用。
Seismometers are important equipments for seismological observation. Their performance parameters can affect the accuracy of the data recorded. And these parameters also play an important role in seismic waveform inversion and calculation of the earthquake’s magnitude. But these parameters may vary as time elapses for lots of reasons. So a seismometer should be calibrated before and after being set on the seismic station time after time.
This article is about the research work on seismometer calibration. It contains three parts: step calibration, sine calibration and compared method of measuring seismometer sensitivity. These three methods are used to get the transfer function of the seismometer.
Step calibration is used to get the characteristic of the seismometer’s transfer function in the low frequency part. The former algorithm for processing step calibration data can not work without people operating the computer. And the results have a large deviation when we calibrate the same seismometer time after time. Therefore, the new algorithm improves the automatism of data processing. Computer can deal with everything and no people have to be involved in. It also improves the stability of the calibration results. The deviation of the results is very small. We calibrate a seismometer with a type of BBVS-60 time after time. And the largest relative deviation is 0.03%.
Sine calibration is used to get the characteristic of the seismometer’s transfer function through the whole band. The former algorithm for processing sine calibration data can not work without people operating the computer, either. The new algorithm also improves the automatism of data processing. It can automatically pick up the waveform to be measured. So no people have to do this boring job again. It can also recover the waveform that is distorted. So the results become more accurate.
This article also introduces a compared method of measuring seismometer sensitivity. It analyzes the relation between the stability of the results and the signal-to-noise ratio. So it can tell us how the noise affects the stability of the results.
The first chapter introduces the background and the meaning of this research work. The second chapter introduces the current methods to calibrate the seismometers, the problems with these methods and some new ideas to solve these problems. The third chapter introduces how to implement these ideas with C codes to make software. The forth chapter introduces the results of experiments with these new methods. The fifth chapter is the summery and the discussion.
The algorithms of step calibration and sine calibration are used in the calibration software which is part of the seismic observatory network project of China. The compared method of measuring seismometer sensitivity is used in the seismic observatory lab now.
本文对地震计台站标定方法进行了研究,包括以下三个方面:阶跃标定、正弦标定和对比测试地震计灵敏度。这三种标定方法都是用来测量地震计的传递函数的。
阶跃标定被用来测量地震计传递函数低频段的特性。原有阶跃标定数据处理算法在进行数据处理的时候需要人机交互。而且,计算结果的稳定性不高。因此,新的阶跃标定数据处理算法主要解决了两个方面的问题--数据的自动处理和计算结果的稳定性。新算法的整个数据处理过程不需要人的参与。计算机可以完全代替人完成日常标定数据的处理工作。数据处理结果具有很小的离散性。经过实验,对一台BBVS-60地震计多次标定所得结果的最大相对偏差是0.03%。
正弦标定被用来测量地震计全频带的传递函数的特性。原有的正弦标定数据处理算法在进行数据处理的时候也需要人机交互。新的正弦标定数据处理程序同样提高了数据处理的自动化程度,对高频和低频波形采用了两种不同的识别方法,能够有效的自动拾取待测波形,实现了计算机自动处理;对于失真的高频数据还能够进行恢复,提高测量精度。
无论是正弦标定还是阶跃标定都只能给出地震计的“相对灵敏度”,而要计算地震计的“绝对灵敏度”就要采用对比测试的方法。本文介绍了对比测试的实验方法和数据处理算法,并通过对地震计输入的功率谱、地震计自身噪音的功率谱和信噪比的分析,说明了噪音对计算结果稳定性的影响。
本文第一章将介绍论文的背景意义。第二章将分别针对阶跃标定、正弦标定和对比测试法,介绍每种测试方法的基本原理、现存问题以及针对问题提出的解决方案。第三章将介绍如何用信号处理和数值分析的方法具体实现解决方案。第四章将列举算法测试的实验结果并对结果进行分析。第五章为全文总结。
本文介绍的正弦标定和阶跃标定算法已经被应用在“中国数字地震观测网络项目”的“标定软件分项”中,并在全国范围内试运行。对比测试灵敏度算法也用Matlab脚本语言实现,并在地震观测实验室中应用。
Seismometers are important equipments for seismological observation. Their performance parameters can affect the accuracy of the data recorded. And these parameters also play an important role in seismic waveform inversion and calculation of the earthquake’s magnitude. But these parameters may vary as time elapses for lots of reasons. So a seismometer should be calibrated before and after being set on the seismic station time after time.
This article is about the research work on seismometer calibration. It contains three parts: step calibration, sine calibration and compared method of measuring seismometer sensitivity. These three methods are used to get the transfer function of the seismometer.
Step calibration is used to get the characteristic of the seismometer’s transfer function in the low frequency part. The former algorithm for processing step calibration data can not work without people operating the computer. And the results have a large deviation when we calibrate the same seismometer time after time. Therefore, the new algorithm improves the automatism of data processing. Computer can deal with everything and no people have to be involved in. It also improves the stability of the calibration results. The deviation of the results is very small. We calibrate a seismometer with a type of BBVS-60 time after time. And the largest relative deviation is 0.03%.
Sine calibration is used to get the characteristic of the seismometer’s transfer function through the whole band. The former algorithm for processing sine calibration data can not work without people operating the computer, either. The new algorithm also improves the automatism of data processing. It can automatically pick up the waveform to be measured. So no people have to do this boring job again. It can also recover the waveform that is distorted. So the results become more accurate.
This article also introduces a compared method of measuring seismometer sensitivity. It analyzes the relation between the stability of the results and the signal-to-noise ratio. So it can tell us how the noise affects the stability of the results.
The first chapter introduces the background and the meaning of this research work. The second chapter introduces the current methods to calibrate the seismometers, the problems with these methods and some new ideas to solve these problems. The third chapter introduces how to implement these ideas with C codes to make software. The forth chapter introduces the results of experiments with these new methods. The fifth chapter is the summery and the discussion.
The algorithms of step calibration and sine calibration are used in the calibration software which is part of the seismic observatory network project of China. The compared method of measuring seismometer sensitivity is used in the seismic observatory lab now.
引文
[1] 中国地震局监测预报司. 数字地震观测技术. 地震出版社. 2003/1:140-141
[2] Charles R. Hutt. Standards for Seismometers Testing. 1990: 2-3
[3]中国地震局监测预报司. 数字地震观测技术. 地震出版社. 2003/1: 143-144
[4] 郑君里,应启珩,杨为理. 信号与系统. 高等教育出版社. 2000: 217-218
[5]张贤达. 现代信号处理. 清华大学出版社. 2002:12-13
[6] Oppenheim, A. V. and R. W. Schafer. Discrete-Time Signal Processing. Englewood Cliffs, NJ: Prentice Hall, 1989
[7] Proakis, J. and D. Manolakis. Digital Signal Processing. 3rd ed. Englewood Cliffs, NJ: Prentice-Hall, 1996
[8] David Kincaid,Ward Cheney. 数值数学和计算. 复旦大学出版社. 1985: 500-501
[9] 郑君里, 应启珩, 杨为理. 信号与系统. 高等教育出版社. 2000: 181-182
[10] 程佩青. 数字信号处理. 清华大学出版社. 2001: 204-205
[11]Forsythe, G. E., M. A. Malcolm, and C. B. Moler, Computer Methods for Mathematical Computations, Prentice-Hall, 1976
[12] William H. Press, Saul A. Teukolsky, William T. Vetterling. c++数值算法. 电子工业出版社. 2005: 297-298
[13] Nelder, J.A., and Mead, R.1965, Computer Journal, vol. 7, pp. 308-313
[14] Lagarias, J.C., J. A. Reeds, M. H. Wright, and P. E. Wright, "Convergence Properties of the Nelder-Mead Simplex Method in Low Dimensions," SIAM Journal of Optimization, Vol. 9 Number 1, pp. 112-147, 1998
[15] 姚天任,孙洪. 现代数字信号处理. 华中科技大学出版社. 1999: 209-210
[16] Cooley, J. W. and J. W. Tukey, "An Algorithm for the Machine Computation of the Complex Fourier Series," Mathematics of Computation, Vol. 19, April 1965, pp. 297-301
[17]Duhamel, P. and M. Vetterli, "Fast Fourier Transforms: A Tutorial Review and aState of the Art," Signal Processing, Vol. 19, April 1990, pp. 259-299
[18]Oppenheim, A. V. and R. W. Schafer, Discrete-Time Signal Processing, Prentice-Hall, 1989, p. 611
[19] Oppenheim, A.V., and R.W. Schafer, Discrete-Time Signal Processing, Prentice-Hall, 1989, pp. 447-448
[20] 叶湘滨等. 传感器与测试技术. 国防工业出版社. 2007: 71-75
[21] Programs for Digital Signal Processing, IEEE Press, New York, 1979, Algorithm 8.1
[22] 程佩青. 数字信号处理. 清华大学出版社. 2001: 44-45
[23] http://baike.baidu.com/view/1060328.html
[24] Welch, P.D, "The Use of Fast Fourier Transform for the Estimation of Power Spectra: A Method Based on Time Averaging Over Short, Modified Periodograms," IEEE Trans. Audio Electroacoustics, Vol. AU-15 (June 1967), pp. 70-73
[25] Hayes, M., Statistical Digital Signal Processing and Modeling, John Wiley & Sons, 1996
[26] Oppenheim, A.V., and R.W. Schafer. Discrete-Time Signal Processing. Upper Saddle River, NJ: Prentice-Hall, 1999, pp. 468-471
[27] L. Gary Holcomb. A direct method for calculating instrument noise levels in side-by-side seismometer evaluations. 1989:89-214
[28]Jon Peterson, Charles R. Hutt, L. Gary Holcomb. Test and calibration of the seismic research observatory
[29] 吕永清, 蔡亚先, 周云耀, 程骏玲. 用 MATLAB 工具精确快速测定宽频带地震计的周期与阻尼系数. 大地测量与地球动力学, 2002, 22(2)
[2] Charles R. Hutt. Standards for Seismometers Testing. 1990: 2-3
[3]中国地震局监测预报司. 数字地震观测技术. 地震出版社. 2003/1: 143-144
[4] 郑君里,应启珩,杨为理. 信号与系统. 高等教育出版社. 2000: 217-218
[5]张贤达. 现代信号处理. 清华大学出版社. 2002:12-13
[6] Oppenheim, A. V. and R. W. Schafer. Discrete-Time Signal Processing. Englewood Cliffs, NJ: Prentice Hall, 1989
[7] Proakis, J. and D. Manolakis. Digital Signal Processing. 3rd ed. Englewood Cliffs, NJ: Prentice-Hall, 1996
[8] David Kincaid,Ward Cheney. 数值数学和计算. 复旦大学出版社. 1985: 500-501
[9] 郑君里, 应启珩, 杨为理. 信号与系统. 高等教育出版社. 2000: 181-182
[10] 程佩青. 数字信号处理. 清华大学出版社. 2001: 204-205
[11]Forsythe, G. E., M. A. Malcolm, and C. B. Moler, Computer Methods for Mathematical Computations, Prentice-Hall, 1976
[12] William H. Press, Saul A. Teukolsky, William T. Vetterling. c++数值算法. 电子工业出版社. 2005: 297-298
[13] Nelder, J.A., and Mead, R.1965, Computer Journal, vol. 7, pp. 308-313
[14] Lagarias, J.C., J. A. Reeds, M. H. Wright, and P. E. Wright, "Convergence Properties of the Nelder-Mead Simplex Method in Low Dimensions," SIAM Journal of Optimization, Vol. 9 Number 1, pp. 112-147, 1998
[15] 姚天任,孙洪. 现代数字信号处理. 华中科技大学出版社. 1999: 209-210
[16] Cooley, J. W. and J. W. Tukey, "An Algorithm for the Machine Computation of the Complex Fourier Series," Mathematics of Computation, Vol. 19, April 1965, pp. 297-301
[17]Duhamel, P. and M. Vetterli, "Fast Fourier Transforms: A Tutorial Review and aState of the Art," Signal Processing, Vol. 19, April 1990, pp. 259-299
[18]Oppenheim, A. V. and R. W. Schafer, Discrete-Time Signal Processing, Prentice-Hall, 1989, p. 611
[19] Oppenheim, A.V., and R.W. Schafer, Discrete-Time Signal Processing, Prentice-Hall, 1989, pp. 447-448
[20] 叶湘滨等. 传感器与测试技术. 国防工业出版社. 2007: 71-75
[21] Programs for Digital Signal Processing, IEEE Press, New York, 1979, Algorithm 8.1
[22] 程佩青. 数字信号处理. 清华大学出版社. 2001: 44-45
[23] http://baike.baidu.com/view/1060328.html
[24] Welch, P.D, "The Use of Fast Fourier Transform for the Estimation of Power Spectra: A Method Based on Time Averaging Over Short, Modified Periodograms," IEEE Trans. Audio Electroacoustics, Vol. AU-15 (June 1967), pp. 70-73
[25] Hayes, M., Statistical Digital Signal Processing and Modeling, John Wiley & Sons, 1996
[26] Oppenheim, A.V., and R.W. Schafer. Discrete-Time Signal Processing. Upper Saddle River, NJ: Prentice-Hall, 1999, pp. 468-471
[27] L. Gary Holcomb. A direct method for calculating instrument noise levels in side-by-side seismometer evaluations. 1989:89-214
[28]Jon Peterson, Charles R. Hutt, L. Gary Holcomb. Test and calibration of the seismic research observatory
[29] 吕永清, 蔡亚先, 周云耀, 程骏玲. 用 MATLAB 工具精确快速测定宽频带地震计的周期与阻尼系数. 大地测量与地球动力学, 2002, 22(2)