马鹏斌   王家松   陈建荣
(西安卫星测控中心  710043)

摘要：为了对中国月球探测工程的提供轨道计算支持，我们研究建立了自己的月球卫星轨道确定模型和软件。荷兰Delft理工大学的Sander Goossens提供了月球勘探者号月球探测器（LP）一个星期的S波段双程多普勒实测数据和2天精密星历，这些数据为检验我们的定轨方案和软件提供了便利。

　　在轨道确定前，我们首先分析了这一个星期LP的轨道变化规律。轨道确定中，采用不同的重力场、不同的行星历表和不同的定轨策略进行了定轨比较。通过重叠弧段比较、外部星历比较以及预报比较,我们分析了LP的定轨和预报精度。结果表明：不考虑初轨误差，我们的轨道预报精度与GEODYN 软件计算的精密星历比较外推48小时误差在4m内；设置1km的初轨误差，我们的轨道确定结果同GEODYN 软件计算的精密星历相差在5m内，其中径向精度好于2m；重叠弧段比较的互差在10m内，其中径向精度好于5m；双程多普勒测量数据的RMS约为0.5mm/s，接近实际的测量误差噪声水平。

关键词：月球勘探者号，轨道确定，精度

Orbit Determination of Lunar Prospector

Ma Peng-bing  Wang Jia-song  Chen Jian-rong
( Xi’an Satellite Control Centre,  Xi’an  710043)

Abstract:   In order to provide orbit completion for Chinese lunar explore project, it was founded the lunar satellite orbit determination(OD) model and software by us. Sander Goossens of Technische Universiteit Delft provided one-week S-band two-way Doppler observations and 2 days precise ephemeris of Lunar Prospector. It is advantageous to test our orbit determination model and software.

Firstly, it is analyzed orbit circulate rule of LP in this week. During OD, comparison with different gravity field, different planetary ephemeredes and different strategies OD will be examined. After comparison with overlay pass, other ephemeris and propagation, it was analyzed the orbit determination and propagation accuracy of LP. The results indicates, no thinking the initial orbit bias, the 48 hours propagation error with the ephemeris by GEODYN within 4m; given 1km bias of initial state, the orbit determination results is different with ephemeris by GEODYN within 5m, 2m in radius; the difference of overlay pass orbit determination with 10m, 5m in radius; the rms of o-way Doppler observations is about 0.5mm/s and close to the measure noise.

Keyword:  Lunar prospector, Orbit Determination, accuracy