摘要
建立了一种特殊坐标系,从理论上推导了磁异常强度、全梯度模信号、张量梯度模信号和拉普拉斯信号等物理信号的表达式,并分析了它们具有的物理性质。采用仿真计算表明:拉普拉斯信号在空间的等值面非常接近于球面,其在平面上的等值线极大值对应磁性目标中心位置,而其它3种信号在平面上等值线极大值与磁性目标中心位置则存在一定的偏差。而且,4种物理信号随测点至磁性目标中心间距离的衰减速度也存在差异,其中,拉普拉斯信号与距离呈5次方衰减,磁异常强度与距离呈3次方衰减,而全梯度模信号和张量梯度模信号与距离都成4次方衰减。
A particular coordinate system is established.Then the expression of magnetic anomaly（MA） intensity,total gradient modules of magnetic anomalies（MATGM）,total gradient contraction of the magnetic gradient tensor（MGTTGC） and Laplace signal（LS） are deduced theoretically,together with their physical properties analyzed.Adopting numerical calculation,the result indicates that the equiscalar of LS is very close to spherical surface in 3D space;accordingly,the maximum value of isoline is corresponding to magnetic object central position.However,the maximum value of other three signals＇ isolines has certain discrepancy with their central position.Moreover,the falloff rate of four signals with the distance between survey point and object center are different,that is,Laplace signal magnitudes that are associated with magnetic objects are proportional to 1/r5 where ＂r＂ is the distance between the sensor and the magnetic object,and MA fields decrease with the inverse cube of distance to the objects.The falloff rate of MATGM is same as MGTTGC,which is proportional to 1/r4.
出处
《海洋技术》
北大核心
2011年第4期105-108,共4页
Ocean Technology
关键词
磁性目标
磁异常强度
全梯度模信号
张量梯度模信号
拉普拉斯信号
magnetic object
magnetic anomaly intensity
total gradient modules of magnetic anomalies
total gradient contraction of the magnetic gradient tensor
Laplace signal
