仪器定向误差对地磁日变化记录准确度的影响研究

Influences of instrument orientation error on the accuracy of daily variation of geomagnetic record

基于红山地磁台磁通门磁力仪GM4-2记录的日变化数据,提出了一种减小仪器定向误差的方法,即D要素磁轴零场漂移S0校正法.首先基于零场漂移S0测量原理,试制测量工具无磁旋转平台,并对磁力仪GM4-2零场漂移S0值进行测量,得出该值约为1 024.7nT;然后在重新定向时对该数值进行误差校正;最后将较正后的零场漂移S0值应用到理论日变化数据和定向后的实际日变化数据中.结果表明,D要素磁轴零场漂移S0是产生定向误差的主要因素,经过零场漂移S0校正后的日变化数据与理论日变化数据一致,消除了由定向误差所造成的日变化畸变,从而能更真实地反映地磁场变化.

Based on the daily variation of geomagnetic data recorded by fluxgate magnetometer GM4-2 at Hongshan geomagnetic observatory, this paper propo- ses a method for eliminating instrument orientation error, namely the correction method for magnetic axis zero drift So of D element. First, based on the mea- surement theory of magnetic axis zero drift So, a rotation platform withoutmagnetism has been trial-produced to measure the So, which is about 1024. 7 nT for the GM4-2. Then, we correct the error of So value in reorientation. Finally, the So value is applied to both theoretical daily variation and daily variation recorded by the instrument after orientation. The results show that the magne- tic axis zero drift So of D element is the main factor for the orientation error. The daily variation recorded by the instrument after orientation are consistent with the theoretical daily variation, thus eliminating the daily variation distor- tion caused by the orientation error, and reflecting the geomagnetic filed varia- tion more realistically.