Application of the spherical harmonic gravity model in high precision inertial navigation systems

作者：Wang, Jing^*; Yang, Gongliu; Li, Xiangyun; Zhou, Xiao

来源：Measurement Science and Technology, 2016, 27(9): 095103.

DOI：10.1088/0957-0233/27/9/095103

• spherical harmonic gravity model
• computational complexity
• appropriate degree
• high precision INS

The spherical harmonic gravity model (SHM) may, in general, be considered as a suitable alternative to the normal gravity model (NGM), because it represents the Earth's gravitational field more accurately. However, the high-resolution SHM has never been used in current inertial navigation systems (INSs) due to its extremely complex expression. In this paper, the feasibility and accuracy of a truncated SHM are discussed for application in a real-time free-INS with a precision demand better than 0.8 nm h(-1). In particular, the time and space complexity are analyzed mathematically to verify the feasibility of the SHM. Also, a test on a typical navigation computer shows a storable range of cut-off degrees. To further evaluate the appropriate degree and accuracy of the truncated SHM, analyses of covariance and truncation error are proposed. Finally, a SHM of degree 12 is demonstrated to be the appropriate model for routine INSs in the precision range of 0.4-0.75 nm h(-1). Flight simulations and road tests show its outstanding performance over the traditional NGM.

• 出版日期2016-9
• 单位北京航空航天大学