基于无奇异变换的卫星广播星历拟合算法

针对导航卫星轨道偏心率近似为0，致使卫星轨道的近地点角距定义模糊，在数据拟合过程中会导致法矩阵（H^TH）奇异的问题，本文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，推导了空间目标位置矢量对基于无奇异轨道根数的广播星历参数偏导数矩阵，利用变换后的观测方程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。最后利用仿真算例验证了所推公式和算法的合理性。

Research on the Fitting Algorithm of Broadcast Ephemeris Parameters Based on Non-Singular Transformation

For navigation satellite’s orbit eccentricity is equal to zero approximately, it would result in the ambiguity of satellite orbit’s argument of perigee and the singularity of the normal matrix in the process of fitting. The new broadcast ephemeris parameters fitting algorithm is developed and it deduces the partial derivative matrix of satellite position vector with respect to modified parameter based on the non-singular transformation. At last, the rationality of formulas and algorithm are validated by simulation.