Acta Geodaetica et Cartographica Sinica ›› 2019, Vol. 48 ›› Issue (2): 238-244.doi: 10.11947/j.AGCS.2019.20180145

• Cartography and Geoinformation • Previous Articles     Next Articles

Symbolic expressions of differences between earth radius

ZONG Jingwen1, LI Houpu1, BIAN Shaofeng1, TANG Qinghui2   

  1. 1. Department of Navigation, Naval University of Engineering, Wuhan 430033, China;
    2. 32022 Troops, Wuhan 430033, China
  • Received:2018-04-10 Revised:2018-09-21 Online:2019-02-20 Published:2019-03-02
  • Supported by:

    The National Natural Science Foundation of China (Nos. 41571441;41771487;41631072)

Abstract:

A systematic and comprehensive comparison of the five commonly used earth radius in geodesy and cartography is carried out, and the differences between the most common points of the earth's radius, their corresponding maximum values, and the latitudes of equal points between themare derived with the help of computer algebraic systems. The symbolic expressionsare expressed as a power series of the first eccentricity. Taking the CGCS2000 ellipsoid as an example, the differences between the commonly used earth radii are clarified to numerical values. The results show that the difference between the commonly used Earth radii has a maximum at 90 degrees and a minimum at 0 degrees. The difference between the average radius of curvature and the equidistant sphere radius is the biggest, and the difference between the average radius of curvature and the average sphere radius is the smallest. These results can provide theoretical basis for relative research in earth science, space science, navigation and positioning.

Key words: earth radius, difference extrema value, extrema value point, symbolic expression, CGCS2000

CLC Number: