Velocity covariance in the presence of anisotropic time correlated noise and transient events in GPS time series
Velocity covariance in the presence of anisotropic time correlated noise and transient events in GPS time series
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DOI：
10.1016/j.jog.2013.08.007
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发表时间：
2013-12-01
影响因子：
2.3
通讯作者：
Jiang, Yan
中科院分区：
文献类型：
--
作者：
Hackl, Matthias;Malservisi, Rocco;Jiang, Yan
GPS时间序列中未建模的暂态事件的存在对噪声特征的估计有很大影响。特别是，受具有优先地理方向的瞬变事件影响的GPS时间序列受各向异性噪声的区域模式的影响。我们提供了一种方法，在存在时间相关噪声的情况下，基于可以解释这种各向异性的速率的Allan方差来推导GPS速度的协方差。计算不同方向的速度方差，从而检测与方向相关的噪声特性。由此产生的协方差为GPS导出的表面速度的不确定性提供了现实的估计，并且对于分析受瞬时信号影响的时间序列特别有意义。我们发现，经历慢滑事件(SSE)的俯冲带中的GPS站点在SSE运动方向上显示出与时间相关的“噪声”的重要分量，并且速度置信度椭圆在该方向上是高度偏心的。在建模并从时间序列中减去SSE之后，这些站点的噪声的时间相关性显著降低，同时估计的速度不确定性的各向异性也随之降低。(C)2013爱思唯尔有限公司。保留所有权利。
The presence of un-modeled transient events in GPS time series significantly influences the estimate of the noise characteristics. In particular, GPS time series affected by transient events with a preferential geographical orientation are affected by a regional pattern of anisotropic noise. We provide a method to derive the covariance of GPS velocities in the presence of time-correlated noise based on the Allan variance of the rate that can account for this anisotropy. The velocity variance is calculated for different directions, allowing for the detection of direction-dependent noise properties. The resulting covariance provides realistic estimates for the uncertainties of GPS derived surface velocities and is of particular interest for the analysis of time series affected by transient signals. We show that GPS sites in subduction zones experiencing slow slip events (SSEs) exhibit a significant component of time correlated "noise" in the direction of the SSE motion and that the velocity confidence ellipses are highly eccentric in this direction. The time correlation of the noise of these sites is significantly reduced after modeling and subtracting SSEs from the time series with a concomitant reduction of the anisotropy of the estimated velocity uncertainties. (C) 2013 Elsevier Ltd. All rights reserved.