Geomagnetic Detection System Based On Three Axis Fluxgate

Autonomous Underwater Vehicle(AUV)has great application prospects in scientific investigation,military,commercial and other aspects.Underwater long-time high-precision self-guided navigation is the key technology that must be broken by underwater submersibles,and it is also a nodus in the domain of navigation research.The earth's magnetic field provides humans with natural navigation resources,and the geomagnetic field database is also a geomagnetic field matching technology.This paper aims to detect multiple magnetic field elements through fluxgate sensors and inertial systems to provide data for geomagnetic field matching.On the basis of a great deal of research on geomagnetic navigation and magnetic field detection,this paper chooses multi-geomagnetic elements navigation as geomagnetic navigation method,selects fluxgate sensor as magnetic field detector device,and adds inertial navigation module to the whole equipment,combines the data of fluxgate and inertial navigation module,and finally obtains multi-geomagnetic elements.For the sake of realizing the detection of magnetic field elements,a three-axis fluxgate detection system based on electromagnetic induction principle is developed,which mainly includes: fluxgate sensor,excitation circuit,induced current,inertia module and upper computer.Firstly,the principle of fluxgate is explained,and the method of magnetic field detection is compared and analyzed.On this basis,according to the characteristics of the weak magnetic field of the geomagnetic field,the toroidal fluxgate sensor of ceramic material was fabricated,and the excitation system and the second harmonic based detection system were designed.The single-chip microcomputer calculates the magnetic field information obtained by the detection system and the off-angle information obtained by the inertial navigation module,and obtains the horizontal component,the vertical component and the total amount.The system test shows that the accuracy of the single component detection system can reach 1nT,and the overall detection accuracy reaches 5nT after analyzing various detection errors,which basically meets the detection requirements.Finally,the zero error,triaxial orthogonal error and inertial yaw error of the whole system are analyzed,and the follow-up work and development direction of this design are proposed.