Effect of lunar gravity models on Chang'E-2 orbit determination using VLBI tracking data

Abstract

The precise orbit determination of Chang'E-2 is the most important issue for successful mission and scientific applications, while the lunar gravity field model with big uncertainties has large effect on Chang'E-2 orbit determination. Recently, several new gravity models have been produced using the latest lunar satellites tracking data, such as LP165P, SGM150J, GL0900D and GRGM900C. In this paper, the four gravity models mentioned above were evaluated through the power spectra analysis, admittance and coherence analysis. Effect of four lunar gravity models on Chang'E-2 orbit determination performance is investigated and assessed using Very Long Baseline Interferometry (VLBI) tracking data. The overlap orbit analysis, the posteriori data residual, and the orbit prediction are used to evaluate the orbit precision between successive arcs. The LP165P model has better orbit overlap performance than the SGM150J model for Chang'E-2100 km × 100 km orbit and the SGM150J model performs better for Chang'E-2100 km × 15 km orbit, while GL0900D and GRGM900C have the best orbit overlap results for the two types of Chang'E-2 orbit. For the orbit prediction, GRGM900C has the best orbit prediction performance in the four models.

Keywords

• Lunar gravity model
• Chang'E-2
• Very Long Baseline Interferometry (VLBI)
• Orbit determination
• Orbit prediction