Acta Geodaetica et Cartographica Sinica ›› 2018, Vol. 47 ›› Issue (11): 1437-1445.doi: 10.11947/j.AGCS.2018.20170659

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Fast Realization of Ultra-high-degree Geopotential Model by Improved Least-squares Method

TIAN Jialei1,2, LI Xinxing1,3, WU Xiaoping1, XING Zhibin1   

  1. 1. Institute of Geospatial Information, Information Engineering University, Zhengzhou 450001, China;
    2. 63850 troops, Baicheng 137000, China;
    3. School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China
  • Received:2017-11-18 Revised:2018-05-14 Online:2018-11-20 Published:2018-11-29
  • Supported by:
    The National Natural Science Foundation of China (Nos. 41274029;41404020;41774018;41504018;41674082);The Self-reliance Project of Information Engineering University (Nos. 2017503902;2016601002)

Abstract: Using the least-squares method to solve the ultra-high-degree geopotential model is very difficult because this method needs to calculate massive data.In this paper,we first analyzed the characteristics of coefficient matrix and normal matrix based on the basic observation equation of geopotential model using the orthogonality of trigonometric function and surface coherence factor.Then,we reduced the matrix solution equation and designed the calculation and storage method of Legendre function based on normal matrix block diagonalization using the increment characteristic of "secondary M" during the process of solving normal matrix by coefficient matrix solution method.At last,the problems of storage and low computational efficiency of large matrix were solved by combining the equator symmetry characteristic of Legendre function,reduction of the matrix solution equation and design of the calculation and storage method of Legendre function.Through the experimental test,the improved method compared to traditional block diagonal method canimprove the efficiency by 300 times,by using this method we can solve ultra-high-degree geopotential model in ordinary PC,and the precision of the model has been improved by 5 orders of magnitude at least when compared with the numerical integral method.At the same time,the accuracy of the original data can be evaluated.

Key words: block-diagonal, least-squares, ultra-high-degree geopotential model, Legendre function

CLC Number: