Spatial Magnetic Field Equalization Compensation of Magnetic Shielding Rooms Based on Multisensor Feedback

Active magnetic compensation (AMC) is essential for maintaining a stable near-zero magnetic environment and improving the signal-to-noise ratio of magnetoencephalography (MEG) measurements based on optically pumped magnetometers (OPMs). However, reducing the overall magnetic field noise level within the uniform area in MEG measurements remains a challenging issue for low-cost miniaturized magnetic shielding rooms (MSRs). This work proposes a spatial magnetic field equalization (SMFE) method based on multi-sensor feedback that addresses two key challenges in spatial magnetic field compensation: sensor delay and weight allocation. First, the active magnetic field compensation system is modeled, and a sensor delay compensation scheme based on the gain-adaptive Smith predictor is established to improve the parameter margin and system performance. Then, the layout of the sensors is designed and the multi-sensor weight allocation scheme is optimized to achieve the spatial magnetic field equalization compensation. Finally, simulation and experimental results on miniaturized MSR demonstrate the effectiveness of the proposed method.