基于地基观测数据2016HO3历表重建与精度分析

Reconstruction and Accuracy Analysis of 2016HO3 Ephemeris Based on Ground Observations

  • 摘要: 小天体历表是小天体探测任务的重要基础支撑数据,工程上和科学上均具有较强的现实意义。针对天问二号任务的探测目标之一近地小行星2016HO3,分析了截止到2022年10月可获得的地基天文观测情况,建立起小天体历表解算流程。拟合后结果表明:赤经和赤纬方向上观测量残差在1.0′′以内,证实了处理流程和解算策略的合理性。重建历表1年尺度上与JPL/Horizons发布的结果比较,两者在赤经和赤纬方向上差异分别小于0.025′′和0.25′′。发现不同权重模型以及观测点取舍对定轨精度有较大影响,扣除2004年的两组观测值并叠加使用vfcc17权重模型时解算历表精度最高,在50年尺度上与Horizons位置差异RMS值为87.39 km。本研究将为我国天问二号小行星探测任务后续测量数据处理提供一定的参考和数据支持。

     

    Abstract: Objectives: The ephemeris of small bodies is an important and basic supporting data in small body exploration missions, which has strong practical significance in engineering and science. This paper aims at the near-Earth asteroid, 2016HO3, one of the exploration targets of the Tianwen 2 mission.Methods: First, we introduce and analyze the available ground-based observation data, and then establish the process of using ground-based observation data to solve the ephemeris of small celestial body, 2016HO3. According to the solving epoch, weighting and observation selection, 16 orbit determination schemes were compared.Results: The results show that the observed residuals after fitting in the right ascension and declination directions are almost within 1.0′′, which confirms the rationality of the data processing flow and the calculation strategy. Compared with the ephemeris published by JPL/Horizons, during one year the differences between the two are less than 0.025′′ and 0.25′′ in the right ascension and declination directions respectively. It has been also noticed that different weighting models and the processing of observations significantly affect the orbit determination of 2016HO3.Conclusions: When using observations excluding two observations at 2004 combined with the vfcc17 weight model, the root mean square of position difference with respect to the ephemeris provided by JPL/Horizons during 50-year is about 87.39 km. This study will provide some reference and basic data support for the measurement data processing of the upcoming Tianwen 2 mission.

     

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