地磁相对记录用低噪声磁通门磁力仪

A Low Noise Fluxgate Magnetometer for Geomagnetic Relative Observation

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,抑制外界温度对传感器输出的影响,获得较低的温度系数,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。采用交变模拟信号处理电路、深度负反馈网络提升仪器的稳定性和线性度;采用D/A转换电路实现仪器对外界自然磁场的自动补偿。通过在零磁空间的性能测试和在观测台站的对比观测,研制的磁力仪噪声指标为峰峰值p-p 0.1 nT、温度系数D分量小于0.1'/℃、H、Z分量小于1 nT/℃。

With the requirements of high resolution,low noise and long-term stability characteristics for geomagnetic relative observation instrument,suppressing the influence of outside temperature on the sensor output and obtaining low temperature coefficient,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,andfiber reinforced plastics frame wrapped with pick-up and compensation coil respectively.Due to alternating amplification and deep feed-back loop,the stability and linearity of the magnetometer are promoted.Using D/A converter circuit,it implements automatic compensation for natural magnetic field.Through performance testing in magnetic field free space and comparison measuring in observatory,the noise parameter of the magnetometer is 0.1 nT p-p（peak-peak value）,and the temperature coefficient of 0.1′/℃ and H,Z components are less than 1 nT/ ℃.