Analysis of POPSAT gravity model errors

The accuracy achievable for a gravity model tailored to a future POPSAT geodetic satellite, and problems in developing such a model were studied. Simulations were performed on the recovery of a limited set of gravity coefficients from single 5-day or 10-day arcs of POPSAT tracking data, acquired with 16 ground stations. These simulations provide conservative estimates on the estimability of the gravity coefficients, on the accuracy of the recovered coefficients and on the contributions of the gravity coefficients uncertainties to errors in the orbit of POPSAT, the positions of ground stations and the pole position. Results demonstrate that, if the other geometric and dynamic models are accurate enough, it is possible to derive from a limited number of actual POPSAT tracking data arcs a tailored gravity model which satisfies POPSAT accuracy requirements after months in orbit.