基于球谐分析的EMM-740的计算及实现  

Calculation and Realizing of EMM-740 Degree Based on Spherical Harmonic Analysis

作　　者：康丽文 陈洁 纪兵[2] KANG Liwen;CHEN Jie;JI Bing(Navy Press,Tianjin 300450,China;Department of Navigation*Naval University of Engineering,Wuhan 430033,China;Guangzhou Marine Geological Survey,Guangzhou 510440,China)

机构地区：[1]海军出版社,天津300450 [2]海军工程大学导航工程系,湖北武汉430033 [3]广州海洋地质调查局,广东广州510440

出　　处：《测绘地理信息》2019年第6期75-78,共4页Journal of Geomatics

基　　金：国家自然科学基金(41476087,41374018,41374082)

摘　　要：针对国内对高精度增强地磁场模型(enhanced magnetic model,EMM)在基于球谐分析时对阶数存在认知偏差、实现模型的软件研究较少以及计算精度不高等问题,考虑了地磁场7要素的关系,建立了基于球谐分析740阶次的EMM模型,给出了Schmidt半标准化缔合勒让德函数,给出了EMM模型的计算步骤,并用MATLAB实现EMM2015模型(2000~2019年)在地球上任意地磁场7要素的计算和等值线图的绘制,将计算值与美国国家海洋和大气管理局公布模型的运行数据进行误差对比分析,各元素的均方根偏差最大为0.86 nT或0.4′,比720阶的EMM模型的精度提高了3倍。结果表明,提供的EMM2015模型软件实现方法具有较高的计算精度,值得推广和应用。There were some problemsin high precision EMM model based on spherical harmonic analysis in China.For example, the degree and order were cognitive errors, the model of the software to achieve was less research and the accuracy of the problem was not high. Considering the relationship between seven elements of geomagnetic field,degree and order 740 for EMM based on spherical harmonic analysis was established, Schmidt quasi-normalized associated Legendre functions and the calculation steps of EMM model are given, and the use of MATLAB to achieve magnetic field seven elements of EMM2015(2000-2019) on the earth with calculation and contour mapping.Comparing the deviation analysis of the software calculated value with NOAA published model of the operating data, the root mean square error were only 0.86 nT or 0.4′. The accuracy of the EMM model is 3 times higher than that of the 720 order model.The results show that the EMM2015 software implementation method has higher computational accuracy and can be promoted and used.

关 键 词：球谐分析 增强地磁场模型2015 NGDC-720 地磁场要素 

分 类 号：P318[天文地球—固体地球物理学] P223[天文地球—地球物理学]