A determination of the ellipticity of the earth's equator from the motion of two satellites

Abstract

The effect of the most important longitude-dependent term of the geopotential on the motion of artificial satellites is expressed by simple formulae. Its numerical coefficient can be interpreted as the ellipticity of the earth's equator; the phase constant Xx gives the geographical longitude of the semimajor axis. Based on photoreduced Baker-Nunn observations of the satellites 1959 al and 195977, the values of these constants were determined to be p (3.21+0.29) X 10-' and Xx= -33?15+0?53.