Resolution Improved Innovation of Coupled Core Fluxgate Magnetometer for Low Frequency Magnetic Field Detection: The Combination of Negative Feedback and Injection Locking

摘要

Coupled core fluxgate magnetometer, which is based on the Hopf bifurcation in bistable nonlinear dynamics, can achieve self-excitation and obtain superior performances compared with the single core fluxgate magnetometer. The detection resolution of CCFM, evaluated by the minimum magnetic field which the magnetometer can clearly identified, is restricted by both the sensor sensitivity and noise floor. In this paper, the resolution improvement of CCFM is achieved by the combination of negative feedback and injection locking, in which the method of negative feedback is utilized to enhance the sensor sensitivity and the concept of injection locking is applied to lower the noise floor. The experimental results have verified that the combination of negative feedback and injection locking is valid to improve the sensor resolution of CCFM for low frequency magnetic field detection.