Orthogonal Fluxgate Technology Is Based On The Principle Of Magnetic Modulation

The weak magnetic measurement is the most basic and important problem in the field of electromagnetic measuring.And the fluxgate is the most practical instruments in weak magnetic measurement.Orthogonal Fluxgates is widely used in navigation. guidance, metal detection and exploration fields for its wide measuring range, high resolution, and low environmental requirements for the measurement.Within its normal range,it can effectively measure the earth’s magnetic field,and can solve measurement problems who’s magnetic is105times lower than the earth’s.With the further development of magnetic materials, researches of Orthogonal Fluxgates have great practical significance.In the work of this paper.beginning with discussion of the principle of magnetic flux modulation and doors,it employs three line drawing method to approximate equivalent to core hysteresis loop,translates the probe output to each harmonic by Fourier series expansion, applies first order Taylor series approximation to derive the relationship between each harmonic and the measured magnetic field. With the concept of simple and reliable.production with high initial permeability, low coercivity of soft magnetic materials(Precision Alloy S1.J81A) of Beiye’s is selected as core probe,square wave with frequency of300Hz and peak value of10V is adopted as excitation signal in design of the fluxgate.Phase-sensitive detection of the second harmonic law is selected to demodulate signal.feedback of the output to the detection coil is performed by the closed loop mode selection short-current law.and then a stable electrical signal proportional to the measured magnetic field is obtained to effectively characterize the magnetic field intensity measured.Analyzing the experimental results with Labview programming spectrum analyzer,the noise immunity of Orthogonal Fluxgates in this paper is283.6pT/Hz@1Hz and its nonlinearity is lower than2%.