直升机时间域航空电磁法补偿线圈

摘要

针对直升机时间域航空电磁法接收信号动态范围过大的问题,一般采用同心补偿线圈减弱一次感应磁场的方法.通过建立同心补偿系统磁场分布模型,利用积分方程和非线性回归的方法对地下发射磁通进行了分析,结合补偿线圈对发射磁矩的影响,得出增大补偿线圈会减弱对地下目标体的探测能力;通过分析发射线圈平面下方的纵向磁场,得出增大补偿线圈会降低接收信号的动态范围同时会减弱近区效应.因此,补偿线圈的大小需根据接收线圈、数据采集系统精度以及飞机的飞行高度等因素进行选取.%To solve the problem of the excessive dynamic range for receiving signals of helicopters by time domain electromagnetic method, concentric bucking coil was used to weaken the primary magnetic field in this paper. A model of magnetic field ' s distribution of concentric bucking system was established. Combining with the analysis of magnetic torque, the magnetic flux was analyzed by means of integral equation and nonlinear regression. It is concluded that the detection ability is weakened as the increase of the bucking coil. Through the analysis of the longitudinal magnetic field below the plane of the transmitting coil, it shows that the dynamic range of the receiving signal is reduced and the near-zone effect is weakened with the increase of the bucking coil. Therefore, the size of the bucking coil can be chosen basied on the receiving coil, accuracy of data acquisition system, as well as the flight altitude of the helicopter.