广播星历参数星上自主拟合算法

Autonomously Updated Broadcast Ephemeris Algorithm

导航星座自主导航要求卫星能自主生成导航电文,针对星载计算机的处理能力有限,引入基于遗忘因子的递推最小二乘估计算法实现快速拟合广播星历。针对导航卫星轨道偏心率近似为0,在数据拟合过程中会导致法矩阵(HTH)奇异的问题,提出基于无奇异变换的广播星历参数拟合算法,引入无奇异轨道根数代替经典开普勒根数,迭代拟合得到改进广播星历参数,再将结果归一化到基于开普勒根数的广播星历参数。利用仿真算例验证了广播星历星上自主拟合算法的合理性。

The navigation constellation＇s autonomous navigation requires the autonomously updating of the broadcast ephemeris. In view of the limited data-processing ability of the satellite, the forgetting factor recursive least-squares algorithm was introduced to improve the data-processing efficiency. Considering that the navigation satellite＇ s orbit eccentricity is equal to zero approximately, it would result in the singularity of the normal matrix in the process of fitting. The new broadcast ephemeris parameters fitting algorithm was developed and the partial derivative matrix of satellite position vector with respect to modified txumneter was deduced based on the non-singular transformation. Finally, the rationality of formulas and algorithm are validated by simulation.