Lunar gravity gradiometry and requirement analysis
Lunar gravity gradiometry and requirement analysis
复制标题
月球重力梯度测量及需求分析
DOI：
10.1016/j.asr.2013.04.009
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发表时间：
2013-08-15
影响因子：
2.6
通讯作者：
Luo, Jun
中科院分区：
文献类型：
--
作者：
Cai, Lin;Zhou, Zebing;Luo, Jun
目前的月球重力场模型大多是从月球探测计划中通过卫星轨道扰动观测或两个低轨道航天器之间的星间测距和测距速率测量得出的。特别是，重力恢复和内部实验室 (GRAIL) 的测量数据已被用于为主要任务和扩展任务生成空间分辨率分别高达球谐度 420 和 660 的月球重力场模型。本文提出了一种利用卫星重力梯度测量的方法，不仅可以较高分辨率地确定月球重力场模型，而且可以较准确地获取中短波长成分信息。尽管该任务推导的模型最大度接近于本研究中讨论的卫星梯度测量所达到的最大度，但与 GRAIL 扩展任务的结果相比，这一优势仍然很明显。基于模拟分析，提出了轨道高度约20 km、任务持续时间约14天、梯度计精度约30 mE/root Hz的任务假设，可确定高精度14 mGal的月球重力场模型和高精度20.5 cm的大地水准面，空间分辨率均为7 km，对应球谐阶数和阶数为789。通过卫星重力测量结果与月球引力势系数之间的直接关系，分析研究了重力梯度测量误差、轨道高度、跟踪精度、任务持续时间和采样率的影响，并通过最小二乘法进行了验证。 (C) 2013 年 COSPAR。由爱思唯尔有限公司出版。保留所有权利。
The current lunar gravity field models are mostly concluded from lunar exploration programs either by observations of satellite orbit perturbations or by intersatellite ranging and ranging rate measurements between two low-orbiting spacecrafts. Especially, the measurements from the Gravity Recovery and Interior Laboratory (GRAIL) have been used to produce the Moon's gravity field models with spatial resolutions up to spherical harmonic degree 420 and 660 for the primary mission and extended mission, respectively. This paper presents a method using satellite gravity gradiometry, which not only can determine a moon's gravity field model with a higher resolution, but also can obtain the medium and short wavelength components information with a higher accuracy. This advantage is still obvious in comparison with the results from GRAIL's extended mission even though the maximum degree of the model derived from the mission is close to that achieved by the satellite gradiometry discussed in this study. Based on the simulations and analysis, a mission with the hypothesis of an orbit height of about 20 km, a mission duration of about 14 days, and a gradiometer accuracy level of about 30 mE/root Hz is proposed, and it permits determination of a lunar gravity field model with a high accuracy of 14 mGal and a geoid with an accuracy of 20.5 cm, both at a spatial resolution of 7 km, corresponding to spherical harmonic degree and order 789. The effects of gravity gradient measurement errors, orbit height, tracking accuracy, mission duration and sampling rate are analytically investigated by the direct relationship between the satellite gravimetry measurements and coefficients of the Moon's gravitational potential, which is verified by the least-squares method. (C) 2013 COSPAR. Published by Elsevier Ltd. All rights reserved.