扩展空间自相关法用于线性阵列时加权拟合问题研究

针对扩展空间自相关法拟合问题,分析了系统误差和方差这两种加权因素,讨论了它们对估算相速度的影响。实验采用10个台站组成的线形阵列。结果表明:有无根据系统误差加权拟合,相速度差别较大;有无根据方差加权拟合,相速度差别较小,但个别值有明显改变;加权前后得到的频散曲线有明显差别。应用扩展空间自相关法时,必须根据系统误差和方差确定合理权值,才能更准确估算相速度。

Study on weighted fitting problem when Expanded Spatial Autocorrelation Method applied to linear arrays

For the fitting problem in the Extended Spatial Autocorrelation method, we analyzed two weighting factors: the systematic error and the variance and discussed the effect of estimating phase velocity caused by them. Linear array which consisted of 10 stations was used in the experiment. The results indicate that whether weight fitting is based on the systematic error or not, great difference can be found in phase velocity; whether weight fitting is based on the variance or not, the difference in phase velocity is relatively slight, but individual values are significantly changed; after the weight fitting, the frequency dispersion curves are obviously different. In the application of the Extended Spatial Autocorrelation method, reasonable weights must be determined according to the systematic error and the variance so as to estimate phase velocity in a more accurate way.