Error analysis of cross-shaped magnetic gradient full tensor measurement system

Abstract

The structural characteristics of the magnetic gradient full tensor measurement system are important factors affecting the accuracy of the magnetic gradient full tensor measurement. In order to analyze the measurement error of the cross-shaped magnetic gradient full tensor measurement system, the theoretical framework and structural configuration of the tensor system that is based on the magnetic dipole model are introduced. Four factors including the resolution, baseline length, target distance, and magnetic moment direction that cause measurement errors are simulated and analyzed. The simulation results show that the resolution, baseline length, and target distance have a great influence on the error of the measurement system. In contrast, the influence caused by the change in the magnetic moment direction is not significant. In a certain area, the resolution increases from 1 nT to 1 fT, and the error percentage of the tensor component Byy decreases the most, reaching 2.1370%. When designing the system structure, it is necessary to comprehensively consider the measurement purpose, design cost, measurement error, and other factors. It is important to select the fluxgate according to actual needs and coordinate the relationship between the baseline length and the measurement distance, which can be effective to decrease the error. The research conclusion can provide theoretical guidance for the design of the cross-shaped magnetic gradient full tensor measurement system.