Hardware Design and Implementation of a High-Precision Optically Pumped Cesium Magnetometer System Based on the Human-Occupied Vehicle Platform  
[PERSON]  
1 School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China; [EMAIL_ADDRESS]  
[PERSON]  
1 School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China; [EMAIL_ADDRESS]  
[PERSON]  
1 School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China; [EMAIL_ADDRESS]  
Specifically, when optically pumped cesium magnetometers are installed on platforms such as human-occupied vehicles (HOVs) [14], researchers can directly carry high-precision instruments to the seafloor to conduct detailed geological surveys and on-site data collection. The application of HOV platforms enables magnetometers to operate in extreme deep-sea environments and allows researchers to make decisions based on real-time data monitoring and analysis. This has revolutionary significance for deep-sea scientific research, resource exploration, and environmental monitoring. Additionally, an optically pumped cesium magnetometer mounted on an HOV provides valuable data for marine biodiversity studies, the health monitoring of seabed ecosystems, and long-term impact studies of global climate change [6].  
[PERSON] et al. studied a towed Overhauser ocean magnetometer for detecting weak magnetic anomalies in 2020. They used an improved adaptive Kalman algorithm to achieve adaptive suppression of magnetic noise in the magnetometer, achieving a sensitivity of 12 pT Hz\({}^{-1/2}\) @ 1 Hz and a dynamic range of 20,000 nT to 100,000 nT [15]. In 2022, [PERSON] et al. analyzed and optimized an autonomous underwater vehicle (AUV) equipped with two three-axis magnetometers for inspecting submarine cables. They proposed a novel two-layer framework that integrates anti-noise cable positioning and robust tracking algorithms to guide AUVs in tracking submarine cables in the presence of sensor noise and ocean currents [16]. Additionally, in 2022, [PERSON] et al. designed a portable VCSEL Pumped Cesium Atomic Magnetometer and compared it with the CS-3. They found that the performance was largely in the same order of magnitude, while their design offered reduced power consumption and a smaller size [17].  
With technological advances, it is foreseeable that these magnetometers will have a profound impacts in more fields, promoting the further development of marine science and related technologies. Therefore, it is of great significance to continuously improve and optimize magnetometer systems. In this study, we adopted a combination of an optically pumped cesium magnetometer and a fluxgate probe. The fluxgate probe is used for the magnetic compensation and selective switching of the cesium optically pumped probes to avoid dead zones, thereby improving the sensitivity, gradient tolerance, and dynamic range of the magnetometer. The performance of the optically pumped cesium magnetometer designed in this work was compared with those of the CS-3 and G-824A magnetometers. Our magnetometer was found to be comparable in terms of performance, while exhibiting lower sensitivity (0.29 pT @ 1 sample/s), larger gradient tolerance (\(\geq\)54,000 nT/m), larger dynamic range (12,165.10-137,992.85 nT), and lighter weight (1.49 kg).