用GPS位移资料计算应变方法的讨论

DISCUSSION ON METHOD OF CALCULATING STRAIN WITH GPS DISPLACEMENT DATA

目前使用相同或类似的GPS资料求应变,不同研究者给出的结果会有显著差别。为此,对用GPS位移(或速度)资料计算应变(或应变速率)的方法进行了研讨。分析后认为,应变计算可以归结成两大类第一类是利用测点附近资料直接求微分或微分的加权平均值的直接计算法;第二类是用解析曲线拟合观测的位移,然后根据该曲线提供的总的趋势求测点的微分值的位移拟合法,这类方法在拟合中又可以分成整体拟合和分片拟合两种。应变计算应该在球面坐标系下进行,根据研究对象和要求,选择适当的方法。

At present,the results from the same or similar GPS data to calculate the strain by different scholars are obviously different. We discuss the method of calculating strain with GPS displacement data. Method of strain calculation can be divided into two kinds.the first one is direct method of calculating differential value or weighted average of differential with data nearby the observating station; the second one is displacement fitting method, it uses analytic curves to fit observation displacement, then calculates the differential value of observation station on the basis of the overall trend from the curves. The second method can be invided into two kinds： the whole fitting and the piecemeal fitting, strain calculation should be done in the spherical coordinate system by chosing suitable method according to research target and requirement.