火星探测器行星际转移段定轨精度评估

Evaluation of Orbit Determination Accuracy in Interplanetary Transfer Section of Mars Probe

天问一号是中国第一次实现地火转移行星际飞行的探测器,在长达202天的行星际转移飞行期间,共经历了4次中途修正及1次深空机动控制,在2021年2月10日成功进行了近火制动,被火星捕获而进入环火轨道。本文对探测器行星际转移期间的动力学模型进行了分析,制定了转移飞行期间定轨积分中心转换原则:在探测器飞出地球影响球后,定轨积分中心需要由地心更换为日心;对不同版本行星星历表的使用进行了分析,确定了使用DE436行星历表进行计算对定轨影响最小。根据探测器行星际转移飞行的特点,制定了一种基于逐日迭代定轨策略的精度评估方法。基于实测数据分析,验证了该方法的有效性,火星探测器行星际转移期间定轨位置误差优于2 km,速度误差优于20 mm·s^(-1)(1σ)。

Tianwen-1 is the first Chinese probe to realize interplanetary flight between Earth and Mars.During the 202-day long interplanetary transfer flight,it experienced four midway corrections and one deep space maneuver control.On 10 February 2021,it successfully applied braking near Mars and was captured by Mars.This paper,the dynamic model during interplanetary transfer is analyzed,and the principle of celestial center conversion during transfer flight is formulated.It is necessary to replace the celestial center with the Sun after leaving the Earth’s influence sphere.According to the analysis results,DE436 ephemeris is determined to be used,because it has the least impact on orbit determination.Based on the characteristics of the interplanetary transfer flight of the probe,this paper proposes an accuracy evaluation method based on a daily iterative orbit determination strategy.Based on the analysis of measured data,the effectiveness of this method has been verified.During the interplanetary transfer of the Mars probe,the orbit determination position error is better than 2 km,and the velocity error is better than mm·s^(-1)(1σ)。