水下磁性目标探测中磁异常分量换算方法

Components Conversion of Magnetic Anomaly in Detecting Underwater Magnetic Object

为了更加准确地判断水下磁性目标空间位置及形态,有必要研究由磁场标量信息向矢量信息换算的方法。根据总强度磁异常与磁异常分量傅里叶变换后的频率域关系,推导由总强度磁异常向磁异常分量换算的公式。利用获取的总强度磁异常,结合测区地磁场方向信息,即可实现标量场向矢量场换算。采用小尺度与大尺度球体以及直立长方体磁场模型对提出方法进行验证,结论表明:换算后垂直分量与理论值存在较小偏差,而水平两个分量与理论值基本吻合;无论剖面测线是否经过磁性目标中心在水平面的投影点,换算的磁异常分量精度差异微小;同时,较小的地磁场方向偏差不会给分量换算精度带来很大影响。

The magnetic object＇s location and shape could be estimated more precisely with its vector information than scalar information.Therefore,the conversion from scalar information to vector information should be studied.With prescribed direction of total field,the rigor formula could be deduced based on the relationship between total field magnetic anomaly and magnetic anomaly components in frequency domain.The method has been testified by sphere and cuboids＇ simulation model.The conclusion shows that the two calculated horizontal components match its theoretical value perfectly,and the vertical component has only little error;the precision is almost the same no matter how section survey line traverses the projection point,moreover,the precision decreases slightly if the geomagnetism direction has little error.