基于小波变换的卫星阻力系数分析

Analysis of Satellite Drag Coefficient Based on Wavelet Transformation

以不同弧长解算天宫一号空间实验室连续55天(d)GPS轨道数据得到卫星阻力系数Cd序列,并对同期的太阳辐射通量f10.7和地磁活动指数ap,Ap序列高、低频多层小波分解。空间环境参量和Cd序列各层信号滑动相关性的统计分析结果表明小波分解的阻力系数序列与对应的f10.7,Ap序列整体具有很好的滞后相关性,验证了通过f10.7,Ap预报Cd的可行性。对不同回归模型和回归分析样本序列长度n,分析Cd预报值残差表明:采用f10.7一元回归模型,并取n=20 d时,Cd预报结果最优。另外,NRLMSIS-00模型在350 km高度的中低纬度区域,地磁活动上升相响应过度,而下降相则响应不足;太阳辐射通量上升相响应适度,下降相响应过度。最后对应用前景进行总结,该方法对提高航天器轨道预报精度具有重要参考价值。

Drag coefficient sequence Cd is obtained by solving Tiangong 1 continuous 55 days （d） GPS orbit data with different arc length. The same period solar radiation flux f10.7 and geomagnetic index ap, Ap sequences are high and low frequency multi-wavelet decomposed. Statistical analysis results of the muhilayer sliding correlation between space environmental parameters and decomposition of Cd show that lag correlation between the satellite drag coefficient sequence after wavelet decomposition and the corresponding level of f10.7, Ap sequence is good. It is also verified that the Cd prediction is feasible. Prediction residuals of Cd with different regression models and different sample lengths are analyzed. The results show that the case setting sample length of 20 days and selecting f10.7 regression model is best. It is also show that NRLMSIS-00 model＇s response in the region of 350 km （Tiangong＇s altitude） and low-middle latitude （Tiangong＇s inclination） is excessive during the ascent phase of geomagnetic activity Ap and is inadequate during decline phase. Additionally, for the low-frequency decomposition sequence NRLMSIS-00 modelg response is appropriate during the ascent rising phase of flo.7. For the high frequency decomposition sequence, NRLMSIS-00 model＇s response is small-scale inadequate during the ascent phase of f10.7 and is excessive during the decline phase of fl0.7- Finally, the summary of potential use and outlook are listed; this method has an important reference value for improving the spacecraft orbit prediction accuracy.