低轨近圆轨道根数变化特征的一种分析方法

Method of Analyzing Low Earth Satellite Near-Circular Orbit Elements

低轨近圆轨道卫星运行周期短，所受摄动力影响大，轨道变化复杂，但在短期内轨道根数的主要变化特性比较简单，主要分为多项式和周期项两部分，这样就可以建立简单的数学模型，进行轨道拟合和预报，从而避免了复杂的摄动模型的求解。研究工作针对某一实际型号的轨道数据，对该卫星轨道第一类无奇点根数进行频谱分析，数学模型的建立，用最小二乘法对数学模型中的参数进行求解。计算结果表明，对低轨近圆轨道根数变化特征的分析正确，轨道根数数学模型简单，拟合结果较好，支持短时间预报，该方法可用于星载GPS定位结果的平滑和预报。

Low earth satellite（LEO） with near-circular orbit has a short-time cycle, strongly affected by perturbative forces, so it is extraordinary complex. However, the orbit elements in short time varies much simpler, as the obvious characteristics include two main parts, polynomial and periodic term. So we can establish mathematic models to fit and predict satellite o-rbit, avoiding from computing complicated perturbative models. The study is engaged in the real orbit data analyzing. Spectn^m of satellite first no-singularity orbit elements is analyzed, and then mathematic models are made in which the parameters are calculated with the least squares. The results show that the analyzing of LEO orbit is right with the simple mathematic models, the right fitting results and the function of predicting in short time. The method can be used as a meaning of smoothing and forecasting in positioning results of GPS onboard.