悬挂式三分量磁通门传感器技术研究

Geomagnetic field is a vector field, geomagnetic observation is the basis of the geomagnetic subject research and development, the performance of monitoring equipment is guaranteed to providing high-quality data. With the requirements of high resolution, low noise and long-term stability characteristics for geomagnetic relative observation instrument, the core as magnetic sensitive element of developed fluxgate sensor is formed by alloy frame of high plasticity, endurance strength wrapped with high permeability permalloy strip and excitation coil, and fiber reinforced plastics frame wrapped with pick-up and compensation coil respectively, for suppressing the influence of outside temperature on the sensor output and obtaining low temperature coefficient. In order to avoid drift due to tilt of the instrument pier which is often the main cause of baseline drift and installation error in the installation process by adjusting the level, a special version of the fluxgate magnetometer is available in which the sensor is suspended to compensate the tilt. Finally, the performance of prototype is developed by the zero magnetic space laboratory testing and observation stations comparing.

地磁场是一个矢量场, 地磁观测是地磁学科研究及发展的基础，观测仪器的性能直接关系到观测数据的准确性和可靠性。针对地磁相对记录要求观测仪器具有高分辨力、低噪声和长期稳定性的特点，研制的磁通门传感器采用高导磁率坡莫合金作为磁芯材料，激励线圈直接缠绕在高塑性、较高持久蠕变强度的环形合金骨架上，感应线圈和补偿线圈缠绕在低温度系数的玻璃钢骨架上，抑制外界温度对传感器输出的影响，获得较低的温度系数；同时采用悬挂磁传感器的方式，消除因观测墩长期观测发生漂移而引入的观测误差，以及观测仪器在安装过程中因水平调节而引入的安装误差。最后，研制的样机通过零磁空间实验室性能测试以及观测台站对比观测，验证其性能指标。

为实现地磁矢量场长期稳定可靠的监测目标，需要高分辨力、低噪声和长期稳定特点的相对记录仪器。本项目研制的磁通门传感器采用高导磁率坡莫合金作为磁芯材料，激励线圈直接缠绕在高塑性、较高持久蠕变强度的环形合金骨架上，感应线圈和补偿线圈缠绕在低温度系数的玻璃钢骨架上，抑制外界温度对传感器输出的影响，获得较低的温度系数；并对传感器的剩磁和噪声起绝对因素的激励信号幅度和频率进行数值计算，采用激励调谐方法获得理想激励波形。研制的样机性能通过零磁装置进行实验室测试，测试结果为：线性度优于2‰、噪声优于0.04nT(RMS)、频带响应DC～5Hz。同时样机采用悬挂磁传感器的方式，消除因观测墩长期观测发生漂移而引入的观测误差，以及观测仪器在安装过程中因水平调节而引入的安装误差。悬挂机构采用具有与特殊钢相当高硬度和耐磨性的铍铜制作成无磁万向节，使其具有自动校平功能，实现以Z轴倾斜±6度内自动调平。目前，样机已在涉县地磁台连续试运行3个多月，其性能与目前地磁台站广泛使用的地磁相对记录仪器性能相当，又因其具有长期稳定性高的特点，同时便于携带和简易架设，非常适用于地震短临跟踪和磁异常区域的加密观测。