In order to consolidate the leading position of high-precision three-component magnetic measurement technology, and supports the breakthrough and exploration level of ore prospecting compared with optical pump aeromagnetic system, the fluxgate UAV aeromagnetic exploration experiment was carried out in a survey area of Shanxi Province (as shown in Figure 1). In the experiment, 6 survey lines were completed with a total length of 90km; The length of the survey line is 6km; East west direction of survey line; The line distance is 100m (as shown in Figure 2), and the point distance is about 0.2m; System sampling rate 70Hz.

The instrument used is fluxgate aeromagnetic system independently developed, and the main performance indicators are:

  Magnetic measuring range:±100000nT;

  Noise level:0.025nT/√Hz;

  Accuracy:≤5nT;

  Deviation angle correction accuracy:±0.008°;

  Operating temperature range:-20℃-70°;

  Probe power consumption:<2W.

  The main performance indexes of the rubidium optical pump aeromagnetic system in the comparative test are:

  Magnetic measuring range:1000nT-100000nT

  Sensitivity:0.001nT/√Hz

  Blind area: ±7°

 Operating temperature range:-30℃-60°

 Maximum gradient tolerance:1000nT/cm

Figue 1 Picture of Fluxgate Aeromagnetic System

Figure 2 Flight Line Diagram

Figure 3 Fluxgate Aeromagnetic Anomaly Map

Through the comparison between the independently developed domestic fluxgate aeromagnetic system and the optical pump aeromagnetic system, the abnormal range is consistent, and the local abnormal details are roughly the same, reflecting the accuracy of the fluxgate aeromagnetic exploration system.

Compared with optical pump aeromagnetism, it has certain advantages: ① there is no dead zone and it can be used in low latitude areas; ② There is no gradient tolerance limit, which can be used in areas with large gradient changes; ③ Fluxgate probe is cheap, only 1/3-1/5 of optical pump probe; ④ Stable performance, not easy to damage, simple maintenance; ⑤ High precision three component fluxgate sensors, unmanned aerial vehicles and other major equipment have been localized to avoid long maintenance cycles; ⑥ Three component measurement of magnetic field can realize three component aeromagnetic measurement.

All technical indicators of fluxgate aeromagnetic system meet the requirements of aeromagnetic specifications; Using the method of repeated line inspection, the total accuracy of calculation is 3.7nt, which meets the working accuracy of 1:10000 on the ground. It is proved that the system has good performance and can be widely used.