Analysis of differences between WMM2020 data and local aeromagnetic data in China

Geomagnetic field is commonly used in mineral resources, geological structures, and spatial electromagnetic environment. In recent years, the application of geomagnetic field in aircraft navigation has received increasing attention. The reliable geomagnetic field data is the foundation for achieving high-precision navigation. Currently the geomagnetic data used in navigation are from mathematical models of geomagnetic field. However, the accuracy of existing geomagnetic field models is low and cannot meet the requirements of high-precision navigation. Therefore, to improve the accuracy of the geomagnetic model data is of great significance. This article mainly studies the deviation between the WMM2020 model data and the unmanned aerial vehicle (UAV) geomagnetic data in two local areas of Weishui in Shaanxi Province and Yuyao in Zhejiang Province, China. Through the analysis of the differences on the north, east and down components of geomagnetic field, it is found that the differences of north and down components in Yuyao area are about 50 nT. And the ones in Weishui area are about 130 nT. The difference of east component is very small in the two areas. After systematic correction, the differences of north and down components are smaller than 40 nT in Weishui area while the ones smaller than 20 nT in Yuyao area. The accuracy of WMM2020 data has been improved greatly in local area in China.