Identification of the earth's geopotential

A method to accurately determine certain constants appearing in mathematical representations of the gravitational field of the earth and other effects such as high altitude drag forces, based on observations of a satellite's orbit is illustrated. The method employs a quasilinearization technique, numerical integration of linear and nonlinear differential equations, least squares fitting criteria and matrix inversion to determine estimates of parameters and initial conditions. Several mathematical representations of the earth's gravitational field are reviewed and current mathematical techniques for the evaluation are discussed. Calculations are performed to verify the method using numerically generated data.