Aeromagnetic system for a Multi-rotor unmanned aerial vehicle based on the Overhauser sensor

Aeromagnetic surveys using unmanned aerial vehicles (UAV) can be used in low-altitude detailed detection of small-scale magnetic anomalies and offers an auxiliary means for geomagnetic survey on land. However, excessive weight of the detection instruments and strong magnetic interference remain problems. To address them, an aeromagnetic system for a multi-rotor UAV based on the Overhauser sensor was designed. To ensure aeromagnetic surveys have high precision and are omnidirectional and fast, a miniaturized Overhauser sensor and a narrow-band tuned filter were designed and a short-time high-precision measurement method was proposed. Furthermore, the ridge regression is used to reduce the adverse effects of multicollinearity and enhance the stability of the compensation coefficient estimators. Both laboratory and flight tests were conducted. Overall, the results show that the static and dynamic noise is 0.029 nT, 0.041 nT, respectively, and the improvement ratio of aeromagnetic interference is 4.38 in the dynamic tests; a test of iron pipe detection was performed to verify the overall performance of the aeromagnetic system.