A miniature magnetic gradient tensor system may be used in small spacecraft for mineral prospecting and detection of unexploded explosive ordnance. The system consists of a magneto-inductive (MI) sensors array, a signal extraction circuit, and a microcontroller. A magnetic gradient full-tensor configuration utilizes four MI sensors arranged in a planar cross structure and is employed to minimize orientation and orthogonality errors. The system's performance was checked by data validation and magnetic anomaly detection. Numerous experimental results demonstrate that the system is able to detect a low-amplitude magnetic field as low as 8.28 nT at 10 Hz, with a typical noise floor of 0.235 nT/Hz$^{1/2}$ at 1 Hz. The system can identify nearby ferromagnetic objects clearly, which indicates its feasibility for weak magnetic anomaly detection.

中文翻译：

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一种用于铁磁物体检测的基于磁感应的磁梯度张量系统的研究

微型磁梯度张量系统可用于小型航天器的矿产勘探和未爆爆炸物探测。该系统由磁感应 (MI) 传感器阵列、信号提取电路和微控制器组成。磁梯度全张量配置利用以平面交叉结构排列的四个 MI 传感器，并用于最小化方向和正交性误差。该系统的性能通过数据验证和磁异常检测进行了检查。大量实验结果表明，该系统能够在 10 Hz 时检测低至 8.28 nT 的低振幅磁场，在 1 Hz 时的典型噪底为 0.235 nT/Hz$^{1/2}$。该系统可以清晰地识别附近的铁磁物体，表明其在弱磁异常检测中的可行性。