两极地区局部点质量模型构建方法

针对两极地区位系数模型计算扰动引力时的奇异问题和点质量模型方程解不稳定问题，分别引入扰动引力去奇异算法和基于换极法的两极地区局部点质量模型构造方法.数值实验结果表明，去奇异算法能有效解决靠近极点处扰动引力计算过程中出现的奇异性问题，基于换极法的点质量模型在两极地区方程结构稳定，精度与位系数模型相当.本文方法可为极区飞行器扰动引力快速赋值提供新的思路. 

Construction of Regional Point Mass Model in Polar Regions

In the traditional polar coordinate system, the latitude and longitude grids will undergo serious deformation in the polar regions. This deformation will cause the design matrix of point-mass model equation unsolvable, and the spherical harmonic method is singular near the two polar points. In this paper, the singularity problem in the calculation of disturbing gravity and the instability problem during the construction of point mass model in polar regions is studied. The singularity elimination algorithm is introduced in spherical harmonic method and the construction of point mass model based on pole transform is proposed. Numerical experiment results show that the singularity elimination algorithm can effectively solve the singularity problem near the poles, and the structure of point mass model based on the pole transform method is stable and the model can achieve the same accuracy compared with the traditional one, which provides a new way for disturbing gravity fast calculation of polar region aircraft.