| The micro-magnetic sensor based on Giant Magneto-Impedance (GMI) effect of amorphous featuring high-sensitivity, quick-response, small and low cost, which can meet the requirement for earth-magnetism navigation, has been widely used in geomag-netic field messurement, environmental monitoring, pedestrian and vehicle navigation and so on. This paper works actively on the geomagnetic detection and terrestrial mag-netic sensor using amorphous materals as the advanced research project.Firstly, based on the analysis of GMI effect and model of the amorphous wires, the AC impedance characterisistics was tested by using the Agilent impedance analyzer. The experimental results show that the magneto-impedance ratio&magnetic field sensitivity are closely interrelated with the length of wires, frequency and amplitude of driving cur-rent, as well as the externally-applied magnetic field. Besides, the technipue index and repuirement of the GMI sensor was also promoted. Then, a single-core and double-core sensors were respectively designed and implemented, which both consist of driving source and signal processing circuits. Calibrations in the magnetic field shield equipment show that the applicaton of negative feedback solenoidal magnetic field improves the linearity and measuring range, and the double-core sensor compensates the drifting of the tempreture and bias magnetic field. Finally, by analyzing the intrinsic connection among the amorphous impedance characterisistics, calibration performance and circuitry design, the faultcause of the sensor was listed. The research shows that the linearity, repeatability and hystesis are mainly determined by the amorphous wires. The method to overcome the disadvantages and optimal design of sensor were also discussed. |
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