An Optimized Design Method for Magnetometer Targeting High-Precision Measurement of Quasi-Periodic Magnetic Field Signal

The closed-loop optically pumped magnetometer (CM) is a noncryogenic sensor with high dynamic range, wide bandwidth, and high sensitivity, and has broad application prospects in the field of cardiac magnetic field measurement. The measurement accuracy of the CM depends on the signal-tracking capability of the system. Conventional CMs have insufficient tracking capability for quasi-periodic signals. It limits the measurement accuracy of the CM for quasi-periodic signals such as cardiac magnetic fields. Based on this problem, a novel method is proposed in this article. The method introduces parallel multi-second-order generalized integral (MS) in the proportional integral-cascade extended state observer (PI-CLESO) to enhance the tracking capability of the CM. In the experiment, the CM’s measurement accuracy of the cardiac magnetic field is improved by 70% by the proposed method. This method is not only applicable to the high-precision measurement of the cardiac magnetic field but also has greater potential for application in the measurement of other quasi-periodic weak magnetic fields.