Research On Electronic Units Of Digital Fluxgate Sensor

Mineral resources relate to the national economic development, and magneticprospecting technique is one of the effective means to explore the mineral resources.Mineral resources in China tend to be surveyed from the shallow to the deep, from thedomestic to foreign countries. Magnetic prospecting technique by satellite is a new trend toachieve the above objectives. The fluxgate sensors with high resolution and widemeasuring range, which are also simple, reliable and durable, are widely used to measureweak magnetic fields with constant or low frequency changes.First, the basic principle and structure of fluxgate sensors under a large amount ofdomestic and foreign researches are introduced. Second, software and hardware designs ofdigital fluxgate sensors, as well as the graphical interface of man-machine interaction, areintroduced. The fluxgate sensor probes are provided by University of Science andTechnology of China. A signal with9.6KHz square wave is used to drive the probe and thesecond harmonic detection method is adopted to detect the output signal. In order toimprove the overall performance, a type of automatic compensation method is also used inthis system. Based on the theory mentioned above, a principle prototype of digital fluxgatesensor is realized. In order to verify the feasibility and accuracy of the principle prototype,a piece of SD card is configured for data acquisition. Comparing the sampling data of oursensor in a whole day in Suzhou laboratory with that of the world’s most advancedmagnetometer in the Ming Dynasty Tombs in Beijing, the consistent test curve of themagnetic field is observed. It’s said by Dr. Du, professor of Institute of Geology andGeophysics Chinese Academy of Science, that the prototype had been very close to theadvanced world level. Further experimental results show that the resolution comes to about0.02nT with a linear dynamic range of about±65000nT. Specifically, it fully meets therequirements of the geomagnetic field measurement.The system has the advantages of small volume, light weight, portable etc., and ittakes an active role in seismic observation, mineral exploration, etc. At last, combined withthe engineering requirements, several corrective measures are raised.