测绘学报 ›› 2015, Vol. 44 ›› Issue (5): 473-480.doi: 10.11947/j.AGCS.2015.20140296

• 大地测量学与导航 •    下一篇

热膨胀效应对GNSS基准站垂向位移非线性变化的影响

姜卫平1, 王锴华2, 邓连生2, 李昭3   

  1. 1. 武汉大学卫星导航定位技术研究中心, 湖北 武汉 430079;
    2. 武汉大学测绘学院, 湖北 武汉 430079;
    3. 卢森堡大学科学技术与通信系, 卢森堡
  • 收稿日期:2014-06-05 修回日期:2014-10-15 出版日期:2015-05-20 发布日期:2015-05-27
  • 通讯作者: 王锴华 E-mail: wkh651010@126.com E-mail:wkh651010@126.com
  • 作者简介:姜卫平(1972—),男,教授,博士生导师,现主要从事空间大地测量和地球动力学研究。 E-mail: wpjiang@whu.edu.cn
  • 基金资助:

    国家863计划(2012AA12A209);国家自然科学基金(41374033)

Impact on Nonlinear Vertical Variation of GNSS Reference Stations Caused by Thermal Expansion

JIANG Weiping1, WANG Kaihua2, DENG Liansheng2, LI Zhao3   

  1. 1. Research Center of GNSS, Wuhan University, Wuhan 430079, China;
    2. School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China;
    3. Faculty of Science, Technology and Communication, University of Luxembourg, Luxembourg
  • Received:2014-06-05 Revised:2014-10-15 Online:2015-05-20 Published:2015-05-27
  • Supported by:

    The National High-tech Research and Development Program of China (863 Program) (No. 2012AA12A209);The National Natural Science Foundation of China (No. 41374033)

摘要:

天线观测墩及基岩的热膨胀效应会造成GNSS基准站坐标时间序列高程方向的非线性变化。本文提出了一种计算热膨胀效应导致的基准站垂向位移的改进方法:首先利用基岩热膨胀模型和基准站地表温度数据,分别计算热膨胀效应对基准站天线观测墩和基岩的影响量;其次,利用最小二乘拟合方法,同时估计模型中周期项的周期、振幅、相位等信息,而已有方法仅估计振幅与相位信息;最后,基于改进的模型,分析了基准站垂向位移的周期性特征变化。本文利用该方法分析了有代表性的9个IGS基准站的数据。结果表明:基岩热膨胀和天线观测墩热效应能造成测站垂直方向位移变化;在分析的基准站中,最大影响分别可达0.57 mm和1.85 mm;热膨胀效应造成的GNSS基准站垂直方向位移时间序列具有周年和半周年周期特性,分别可以解释测站U方向坐标时间序列季节性变化的11.2%和3.3%,影响大小随测站纬度的增加而增加,且半周年影响明显小于周年影响;同时,部分测站发现了其他小周期的影响(约51 d)。此外,基于该方法,选取了全球107个IGS站,计算了热膨胀造成的各测站垂向位移周年振幅及其相位,结果显示周年振幅最大可达3.3 mm,其大小和测站纬度具有比较明显的相关性。

关键词: 热膨胀, 垂向位移, 周期变化, 最小二乘拟合

Abstract:

Thermal expansion of GPS monuments and nearby bedrock could result in vertical changes in the coordinate time series of GNSS reference stations. In this paper, an improved method was developed to compute the magnitude of vertical variations caused by thermal expansion. Firstly, we calculated the effect on GPS monument and bedrock caused by thermal expansion based on land surface temperature data of GNSS reference stations and thermal expansion model. Secondly, we estimated the circular frequencies, amplitudes and phases using the method of least squares fitting instead of the current method which estimated only the amplitudes and phases information. Finally, we studied the periodic characteristics of the vertical variations caused by our modified thermal expansion model. Through analyzing the results of 9 representative IGS stations, we concluded that thermal expansion of GPS monuments and nearby bedrock could result in vertical variations of GNSS stations. The maximum variations could reach up to 0.57 mm and 1.85 mm at these stations respectively. The vertical variation caused by thermal expansion exhibited both annual and semiannual characteristics, which could explain 11.2% and 3.3% of the total annual and semi-annual variations in the up component of the coordinate time series respectively, and the magnitudes became larger with the increasing of their latitudes. Meanwhile, the amplitudes of the annual variations were much larger than that of the semi-annual variations. Meanwhile, some other small period (about 51 days) was also detected at some of these stations. In addition, we chose 107 IGS reference stations and computed the annual amplitudes and phases caused by thermal expansion of all these stations based on the method aforesaid. The results show that the maximum annual amplitude can reach to 3.3 mm, and their magnitudes show positive correlation with their latitudes prominently.

Key words: thermal expansion, vertical variation, periodic variation, least squares fitting

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