天问一号拓展任务对火星低阶重力场解算的潜在贡献分析  

Potential Contribution of Tianwen-1 Extended Mission to Mars Low-Order Gravity Field

作　　者：刘山洪 鄢建国[1] 杨轩 叶茂[1] 郭茜 王波 李斐[1] LIU Shanhong;YAN Jianguo;YANG Xuan;YE Mao;GUO Xi;WANG Bo;LI Fei(State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430079,China;National Key Laboratory of Science and Technology on Aerospace Flight Dynamics,Beijing 100094,China;Beijing Aerospace Control Center,Beijing 100094,China;State Key Laboratory of Satellite Navigation System and Equipment Technology,Shijiazhuang 050081,China)

机构地区：[1]武汉大学测绘遥感信息工程国家重点实验室,湖北武汉430079 [2]航天飞行动力学技术重点实验室,北京100094 [3]北京航天飞行控制中心,北京100094 [4]卫星导航系统与装备技术国家重点实验室,河北石家庄050081

出　　处：《武汉大学学报（信息科学版）》2023年第1期58-64,共7页Geomatics and Information Science of Wuhan University

基　　金：国家自然科学基金(42030110,U1831132,12203002);武汉大学地球空间环境与大地测量教育部重点实验室开放基金(21-01-01);民用航天预研项目(D020103)。

摘　　要：天问一号是中国首次独立开展的行星际探测任务,实现了对火星的环绕、着陆、巡视探测。天问一号正常科学任务阶段环绕以极轨设计为主,与历史火星任务类似,对当前火星重力场模型精度改进有限,因此其拓展任务轨道选取至关重要。通过对极轨圆轨道和近赤道大偏心率轨道进行仿真模拟,分析两种典型轨道构型对现有火星重力场模型改进的可能性,基于不同误差考量仿真解算了对应6个重力场模型。借助重力场功率谱分析,发现在测量噪声为0.1 mm/s的情况下,不论采用极轨还是近赤道轨道,一个月的跟踪数据均可较好地反演出42阶次的火星重力场模型;考虑综合误差影响之后,发现两种轨道对于重力场解算精度类似,其中实施近赤道大偏心率轨道对35阶次以上约束略强。Objectives:Tianwen-1 is the first independent interplanetary mission of China,and it was launched on 23 July 2020 and delivered directly into the Earth-Mars transfer orbit,which arrived at Mars in February 2021.It will complete orbiting,landing,and roving tasks in one operation.Exploiting tracking data from gathered during this science exploration and extended mission,this paper explores possible ways to improve the Mars gravity field model by simulation.Methods:We designed two types of orbits,including the polar orbits with near zero eccentricity and the near equatorial orbit with large eccentricity.Based on these two types of orbits,we recovered six gravity solutions considering various error sources,such as measurement noise,solar pressure error,rotation model error,and tracking time length.We used the power spectrum method to analyze and evaluate these recovered gravity models.Results:We find that a month of tracking data from the polar orbit or the combined polar and near equatorial orbit could be used to properly reconstruct the Mars gravity field model with orders and degrees of 42 under the 0.1 mm/s measurement noise.When 10%solar pressure error is added,the gravity model solution only suffers a slight influence showing in the power spectrum analysis.Furthermore,when Mars rotation model error is added,the degree variances of gravity models are affected only after the 35-order and degree.Conclusions:The results show that considering the influence of comprehensive error,the accuracy of gravity field solutions of the two types of orbits is similar.Nevertheless,the orbit with large eccentricity near the equator has a slightly stronger constraint on more than 35-order and degree coefficients.Besides,when the track tracking data collected from the near equatorial orbit phase are added in the recovering of Mars gravity model,the proposed model can improve the precise orbit determination accuracy of a spacecraft with near-equatorial orbit.

关 键 词：火星重力场 GGM-3 功率谱 天问一号 

分 类 号：P228.1[天文地球—大地测量学与测量工程]