基于空间碎片激光测距的高层大气密度测量研究

The upper atmosphere causes drag to Low Earth Orbit (LEO) spacecrafts. Atmospheric density is the primary factor of orbit-perturbing drag force. The density of upper atmosphere is influenced by space weather in a complicated manner. Measuring upper atmosphere density is important for space weather research and spacecraft operations. In recent years, diffuse-reflection based laser ranging technique has lead to dramatical increase of possibility to precisely measure and determine many objects. This gives new opportunity to upper atmosphere research. This project bases on satellite laser ranging (SLR), space debris laser ranging and orbital dynamics research in Changchun Observatory. It combines satellite laser ranging and electro-optical tracking technology to research space debris tracking and improve the orbit accuracy. It aims to solve for atmospheic density and related model by using space debris orbit data to make substantial supplement to SLR network data. It then assesses the impact of the resulting atmospheic model improvement on LEO orbit accuracy with predition accuracy as criterion.

高层大气对低轨道航天器产生阻力，其密度是摄动阻力的主要影响因素。高层大气密度受空间天气影响，变化规律复杂，精确测定高层大气密度对空间天气研究及航天器测控有重要意义。近几年漫反射激光测距技术的成熟，使得可精确测定轨的空间目标成倍增加，为高层大气研究打开了一扇新的窗口。 本项目在长春人造卫星观测站现有激光测卫、激光测空间碎片及轨道动力学研究工作基础上，拟结合激光测距技术和光电观测手段，通过空间碎片的观测研究，提高其测定轨精度；将空间碎片作为激光联测卫星的重要补充，用于解算高层大气密度和改进大气模型；以预报精度为指标，探讨改进大气模型对低轨道空间目标测定轨精度的影响。

本项目以空间碎片轨道摄动为切入点，研究地球高层大气的变化。在项目研究期间，建立了空间碎片目标数据库，采集了必要信息，对目标外形尺寸、截面积和弹道系数等重要参数进行了估计，为大气密度的反演提供了基础。研究和改进了激光测距资料的单站定轨方法，以预报精度为指标，验证了方法的有效性，达到国内领先水平。发现和持续观测特殊火箭体目标，积累了长期的常规激光测距观测资料，数量质量均为国际领先。成果的部分数据在关键目标的陨落期预报研究中发挥重要作用。