EIT信号对CPT磁力仪弱磁测量性能的影响

针对现有磁力仪测量数百纳特斯拉弱磁场存在精度低和便携性差等问题,提出一种通过压窄CPT磁力仪EIT信号线宽来实现弱磁场测量的方法.该方法是根据EIT信号磁场测量仿真模型,采用相敏检波二阶微分信号获得磁力仪灵敏度系数,并根据最佳灵敏度系数分析得出EIT信号分离条件及其线宽对弱磁场测量性能的影响.仿真和试验结果表明:具有窄...

Influence of EIT signal on weak magnetic measurement performance of CPT magnetometer

Aiming at the problems of low accuracy and poor portability in measuring the weak magnetic field of hundreds of nT by the existing magnetometer,a method for measuring the weak magnetic field by narrowing the line width of the EIT signal of the CPT magnetometer was proposed,which based on the EIT signal simulation model of magnetic field measurement.The magnetometer’s sensitivity coefficient was obtained by using the phase sensitive detection second-order differential signal.Then based on the best sensitivity coefficient analysis,the EIT signal separation conditions and line width on the weak magnetic field measurement performance were acquired.The simulation and test results showed that CPT magnetometer with narrow EIT signal line width can measure 100 nT magnetic induction.Finally,the linearity and noise tests of the CPT magnetometer were conducted after narrowing line width of the EIT signal.The test results showed that the maximum nonlinear error of the magnetometer was 0.9537 nT within the range of 100~500 nT of the magnetic induction.Under the background of 100 nT magnetic field,the output noise of the magnetometer was 20.26 pT/Hz^1/2@1 Hz.