Influence of the Choice of Lunar Gravity Model on Orbit Determination for Lunar Orbiters

• Published in: Mathematical problems in engineering Vol. 2018; no. 2018; pp. 1 - 17
• Main Authors: Kim, Bang-Yeop, Bae, Jonghee, Song, Young-Joo, Kim, Young-Rok
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2018; Hindawi; Hindawi Limited
• Subjects: Accuracy; Antennas; Communications satellites; Computer simulation; Computing time; Covariance; Deep Space Network; Gamma rays; Gravitation; Gravity; Ground stations; Laboratories; Lost & found property; Lunar Orbiter; Mathematical problems; Orbit determination; Polar orbits; Program verification (computers); Research centers; Science; Simulation; Studies
• ISSN: 1024-123X; 1563-5147
• DOI: 10.1155/2018/5145419

We examine the influence of the lunar gravity model on the orbit determination (OD) of a lunar orbiter operating in a 100 km high, lunar polar orbit. Doppler and sequential range measurements by three Deep Space Network antennas and one Korea Deep Space Antenna were used. For measurement simulation and OD analysis, STK11 and ODTK6 were utilized. GLGM2, LP100K, LP150Q, GRAIL420A, and GRAIL660B were used for investigation of lunar gravity model selection effect. OD results were assessed by position and velocity uncertainties with error covariance and an external orbit comparison using simulated true orbit. The effect of the lunar gravity models on the long-term OD, degree and order level, measurement-acquisition condition, and lunar altitude was investigated. For efficiency verification, computational times for the five lunar gravity models were compared. Results showed that significant improvements to OD accuracy are observed by applying a GRAIL-based model; however, applying a full order and degree gravity modeling is not always the best strategy, owing to the computational burden. Consequently, we consider that OD using GRAIL660B with 70 × 70 degree and order is the most efficient strategy for mission preanalysis. This study provides useful guideline for KPLO OD analysis during nominal mission operation.