基于轨道预报的热层模式评估

Assessment of Thermosphere Models Based on Orbit Prediction

在太阳活动高低年的地磁平静/扰动环境下,利用不同热层大气模式J77,DTM78,MSIS00,JB2008和CHAMP加速度计反演密度,分析有无先验信息条件下的轨道预报误差.结果表明无先验信息的精密轨道预报中,热层模式的性能可能被弹道系数等参数偏差干扰,此时预报误差不能作为模式性能的评价标准.先验信息对轨道预报精度提升非常明显,尤其是地磁扰动期先进热层模式性能得以展现,轨道预报误差为无先验信息情况下的10%~25%.目前热层模式的主要缺陷存在于地磁扰动期.各模式之间的差异是:JB2008模式可以通过线性和单一频率周期项补偿,而J77及DTM78等模式还存在更多频率的误差.本文对不同情况下精密轨道预报的研究结果可为空间碎片碰撞预警等工程实践提供参考.

The LEO prediction error was studied with thermosphere models including J77,DTM78,MSIS00,JB2008 and the CHAMP derived density.In precise orbit prediction without prior information,the performance of the thermosphere model may be erased by uncertainties of those parameters such as the area mass ratio,and the prediction error cannot be used as the criteria for performance evaluation of those models.The prior information can be used to improve the accuracy of those orbit predictions,especially during the geomagnetic disturbed period.The orbit prediction error is averagely about 10%~25% compared with the situation without prior information.The main defects of thermosphere models exist currently in the geomagnetic disturbed period.The difference between models is that JB2008 model can be compensated by single frequency plus linear items,but J77,DTM78 models can’t.This paper introduces new insights to the precise orbit prediction under different conditions,which can be used as tutorial materials to provide reference for the engineering practice of space debris collision warning.