MicrOBEM: a micro-ocean-bottom electromagnetic receiver
LUO Xian-Hu1(), DENG Ming2, QIU Ning3,4, SUN Zhen3,4, WANG Meng2, JING Jian-En2, CHEN Kai2()
1. Institute of Marine Technology Methods, Guangzhou Marine Geological Survey, Guangzhou 510076, China 2. School of Geophysics and Information Technology, China University of Geosciences(Beijing), Beijing 100083, China 3. Key Laboratory of Marginal Sea Geology of CAS, South China Sea Institute of Oceanology, Guangzhou 511458,China 4. Southern Ocean Science and Engineering Guangdong Laboratory (Guangzhou), Nanhai Ocean Institute,Guangzhou 511458,China
Ocean bottom electromagnetic receivers (OBEMs) are mainly used for high-precision observation and measurement of magnetotelluric signals and controlled-source electromagnetic signals at the sea bottom. To overcome the shortcomings of large volume, high power consumption, and high cost of the existing OBEMs (OBEM-Ⅲ type), this study conducted technical research regarding miniaturization, low power consumption, and low cost. As a result, the overall power consumption of the existing OBEMs (OBEM-Ⅲ type) has been reduced from 1 600 mW to 500 mW or less (by equipment of inductive magnetic sensors) due to the development of a low-power control unit and preamplifier, the installation of low-power fluxgate sensors, and adoption of advanced power management technology. Traditional acoustic releasers are expensive and bulky and require more suitable buoyant materials. By integrating the underwater acoustic communication module and being equipped with the external erosion wearing release device, the MicrOBEMs make release and recovery possible using only a 17-inch glass sphere, thus greatly reducing the volume and hardware cost of the instrument and improving the integration and operation efficiency of devices. Compared to the OBEM-Ⅲ type, the volume, power consumption, and cost of the newly developed MicrOBEMs are reduced by 3/4, 2/3, and 1/2, respectively. A deep-water geomagnetic test was conducted in March 2021 in the southern South China Sea, preliminarily verifying the geomagnetic measurement function of the MicrOBEMs and reflecting that the MicrOBEMs have the advantages of small size, low power consumption, and low cost.
基金资助:国家自然科学基金项目“拖曳式海洋可控源电磁法电场运动噪声压制与信号增强方法研究”(42174081);“海底MT的运动海水电磁噪声分离方法研究”(41804071);南海U形海疆线综合研究团队项目“U型海疆线—U boundary in the South China Sea”(2019BT02H594);广东省基础与应用基础研究基金项目“南海珠江口陆坡天然气水合物的电磁和地震联合反演解释研究”(2021A1515011526)
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