MISI90大气密度模型在定轨中的参数输入方式探讨

Parameters Input of MSIS90 Thermosphere Density Model in Orbit Determination and Forecasting

大气密度模型对以载人飞船为代表的低轨航天器精密定轨及轨道预报有很大影响。在载人航天工程中使用的大气密度模型对于地磁指数和太阳辐射流量的输入有两种方式,即输入固定值和输入分段值。利用MSIS90模型,通过天宫一号目标飞行器的轨道数据分析对比了不同参数输入方式,不同数据长度以及不同地磁指数对定轨和轨道预报的影响。结果表明,数据弧段短且地磁变化不大时,输入固定值的方式获得的轨道预报精度较高;长弧段定轨和长期轨道预报的场合下输入分段值的方式预报精度高,稳定性好,适用范围广,操作更简单。

Thermosphere density model plays an important role in low Earth satellites orbit determination and forecasting. There are two ways to input geomagnetic and solar radiation parameters when using thermosphere models, namely, fixed parameters input and variable parameters input. Using MSIS90 model and Tiangong-1 orbit data, the precision of orbit determination and forecasting is analyzed with different input methods of parameters, different length of data and different geomagnetic parameters. Results show that the method of fixed parameters input is better with less observation data in geomagnetic quiet condition. However, in long-term orbit forecasting with more observation data, the method of variable parameters input is more accurate and easier to operate.