基于姿态变化的航空频率域电磁法仪器偏置实时校正方法研究  

Bias real-time correction of airborne frequency domain electromagnetic system based on attitude change

作　　者：李光[1,2,3] 渠晓东[1,2,3] 陈洁[1,2] 黄玲[1,2] 方广有[1,2] 

机构地区：[1]中国科学院电子学研究所,北京100190 [2]中国科学院电磁辐射与探测技术重点实验室,北京100190 [3]中国科学院大学,北京100049

出　　处：《地球物理学报》2016年第10期3917-3926,共10页Chinese Journal of Geophysics

基　　金：国家重大科研装备研制项目"深部资源探测核心装备研发"子项目"航空瞬变电磁勘探仪"(ZDYZ2012-1-03-05)资助

摘　　要：磁偶极子的航空频率域电磁法仪器在飞行测量的过程中由于仪器偏置的存在,且仪器偏置会随着外部气压、温度等环境因素以及收发线圈晃动的影响而呈现非线性变化,使得观测数据出现误差,因此需要对仪器偏置进行校正.而传统的在测线飞行前后将仪器抬至高空的"零场值"标定方法具有成本高、受测区环境影响大以及采用线性插值获取测线飞行过程中仪器偏置的精度低等缺点.本文根据仪器偏置与仪器姿态角变化无关的特性,通过测得仪器的姿态角信息,在满足重叠偶极子模型的条件下,实现对仪器偏置的高精度实时校正.模型仿真结果表明,在30m常规飞行高度下,该方法实时测得的仪器偏置精度接近于110m高空测得的精度;校正后仪器偏置的绝对误差与理论二次场的比值即相对误差小于5%,满足反演大地电导率的精度要求.该方法不仅减少了飞行的工作量,降低了飞行成本和飞行难度,而且可更加精确地获得测线飞行过程中仪器偏置的非线性变化值,提高航测数据的观测精度.There exists bias for airborne frequency domain electromagnetic instruments which are based on magnetic dipole in the course of flight measurement,and the bias will present nonlinear changes with the change of external air pressure,temperature and other environmental factors and the sway of the transmitter and receiver coils,leading to errors in observation data,so it is necessary to calibrate the bias.The traditional method,＂zero field＂calibration method,which moves the instrument to a high altitude before and after the flight measurement has a high cost,can be greatly affected by the zone environment,and has low precision by using linear interpolation during the flight.Based on the feature of not varying with the change of attitudeangles,the bias of airborne frequency domain electromagnetic instruments can get real-time correction with high-precision during flight measurement by measuring the attitude angles,while meeting the condition of superposed dipole model.The model simulation shows that at the routine flight height of 30 m,the precision of bias measured by this method is close to the precision of bias measured at a height of 110m;the relative error of bias absolute error over the secondary field is less than 5% after correction,meeting the accuracy requirements of ground conductivity inversion.This approach not only reduces the workload and cost of flight,but also can more accurately obtain the nonlinear changes during flight measurement,improving the accuracy of aerial observation data.

关 键 词：航空频率域电磁法 实时 偏置 姿态角 重叠偶极子模型 

分 类 号：P631[天文地球—地质矿产勘探]