GNSS时间序列自动化处理方法及其在沿海地区的应用

    Automated GNSS time series processing method and its application to coastal areas

    • 摘要: 复杂监测环境及变形模式会导致变形监测获取的全球导航卫星系统(Global Navigation Satellite System,GNSS)时间序列包含多源异构误差和信号,为满足GNSS时间序列高精度变形信号提取的需求,本文研究了一种基于异常值、阶跃项和误差值单独改正的GNSS时间序列自动化处理方法。首先讨论分析各种误差项的数值变化特性,再分别利用均值及标准差、数据连续性判别和变形特征函数拟合的处理策略,对GNSS时间序列中的异常值、阶跃项和误差值进行改正处理,以此提高GNSS时间序列的精度和可靠性,获取准确的变形信号。为验证方法的有效性,对苏门答腊岛43个GNSS站点近8年的时间序列进行自动化处理,估算获得的位移速率表现出相似的变化特征且与实际情况一致,E方向表现为20~35 mm/年的东向运动,N方向表现为15~30 mm/年的北向运动,U方向表现为10 mm/年以内的抬升或沉降,验证了本文提出方法在位移速率估计方面的可靠性。此外,实验结果还表明,本文方法能够有效实现异常值识别与剔除、阶跃项修复、误差值改正、变形特征参数估计及其不确定性评估,从而为基于GNSS时间序列的科学研究及工程应用提供准确可靠的数据,适用于沿海地区复杂监测环境中GNSS时间序列的自动化处理。

       

      Abstract: Complex monitoring environments and deformation patterns can cause the Global Navigation Satellite System (GNSS) time series acquired by deformation monitoring to contain multi-source heterogeneous errors and signals, in order to meet the demand for high-precision deformation signal extraction from the GNSS time series, this paper investigates an automated processing method for GNSS time series based on individual corrections for outliers, step terms and error values. Firstly, this paper discuss and analyze the numerical change characteristics of various error terms, and then use the processing strategies of mean and standard deviation, data continuity discrimination and deformation characteristic function fitting to correct the outliers, step terms and error values in the GNSS time series, so as to improve the accuracy and reliability of the GNSS time series and obtain accurate deformation signals. In order to verify the validity of the method, the time series of 43 GNSS stations in Sumatra Island for the past 8 years were processed automatically, which showed that the estimated displacement rates showed similar characteristics and were consistent with the actual situation, with an eastward motion of 20-35 mm/year in the E direction, a northward motion of 15-30 mm/year in the N direction, and an uplift or subsidence of 10 mm/year in the U direction, thus verifying the validity of the method proposed in this paper for estimating displacement rates. In addition, the experimental results also indicated that the method in this paper can effectively realize the identification and removal of outliers, the repair of step terms, the correction of error values, the estimation of deformation characteristic parameters and the assessment of uncertainty, so as to provide accurate and reliable data for scientific research and engineering applications based on the GNSS time series, and it is suitable for the automated processing of the GNSS time series in the complex monitoring environment of the coastal area.

       

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