The use of laser altimetry data in Chang'E-1 precision orbit determination

Accurate altimetric measurement not only can be applied to the calculation of a topography model but also can be used to improve the quality of the orbit reconstruction in the form of crossovers. Altimetry data from the Chang'E-1 (CE-1) laser altimeter are analyzed in this paper. The differences between the crossover constraint equation in the form of height discrepancies and in the foim of minimum distances are mainly discussed. The results demonstrate that the crossover constraint equation in the form of minimum distances improves the CE-1 orbit precision. The overlap orbit performance has increased similar to 30% compared to the orbit using only tracking data. External assessment using the topography model also shows orbit improvement. The results will be helpful for recomputing ephemeris and improving the CE-1 topography model.