Individual geopotential harmonic coefficients of order 15 from 30 resonant satellite orbit analyses

The results from 30 15th-order resonant satellite orbit analyses are used to determine individual tesseral harmonies of order 15 in the Earth's geopotential. The equations are solved by a modified least-squares method to determine 11 C and nine S tesseral harmonic coefficients of odd degree and 11 C, S pairs of even degree. For degree 15 to 23 the average standard deviation is 9 × 10-10, corresponding to an error of 6 mm in geoid height. The resonance values thus provide a strict independent standard of comparison for comprehensive geopotential models. The models emerge well from such tests, and the most recent models, GRIM4-C1, GEM T3 and JGM-1, are closest to the resonance values.