Magnetic measurement error interference model construction and time domain frequency domain analysis of USV

Abstract Unmanned surface vehicle (USV) is a common vehicle for marine exploration and marine search and rescue, the research on the accuracy of navigation and positioning is one of its key technologies. In the paper, we focus on the problems of high noise and unclear disturbance law of actual magnetic measurement values in the combined positioning of USV. It mainly includes the study of the numerical variation law of static and dynamic magnetic measurement of USV. Firstly, we constructed a new comprehensive interference model for dynamic magnetic measurement of USV. The model mainly includes the factors of hard-iron errors and soft-iron errors of magnetic measurement, in which the soft-iron errors add the effect of wave and hull steering. Subsequently, the time-domain and frequency-domain analysis methods were used to investigate the size and variation law of the of the magnetic measurement noise, which originated from wind-wave disturbances and the USV’s directional changes during dynamic magnetic measurements. The results show that the change of magnetic measurement can reach 1000 nT when the USV is up and down with the wave, and there is about 300 nT change value of magnetic measurement when the direction of the USV is changed. These studies can provide a research basis for noise reduction and compensation of magnetic measurement in the dynamic navigation of USVs.