自主导航星座旋转误差的差分校正技术

基于星间观测的自主导航星座存在整体旋转不可测问题，一旦星座发生整体旋转，将导致地面用户定位结果存在偏差.针对这一问题建立了地面用户定位误差模型，运用定位原理和球坐标系变换，从数学上推导了星座整体旋转偏差和地面用户定位偏差之间的关系，在此基础上提出了基于差分原理的旋转误差校正技术，并给出了系统组成和校正算法.使用Walker 12/3/1星座的仿真表明，导航星座旋转误差将导致地面用户的大地经度出现相同角度的偏差，地面用户使用差分校正技术后可有效校正这一误差，在星座整体旋转误差小于1'（相当于赤道地区31 m的水平误差）的条件下，地面用户经差分校 正后的水平误差小于 1.5 m，高程误差小于0.003 m.

Differential correction technique to the rotation error in autonomous navigation constellation

The rotation of the autonomous navigation constellation is unobservable while using inter-satellite measurements only. Once the rotation occurs, errors will be introduced to the positioning results of ground users. The positioning error model of ground users was established to solve this problem. According to the positioning principle and spherical coordinates transformation, the relationship was mathematically proved between the rotation error of the constellation and the positioning error of ground users. Based on this relationship, a differential correction technique to the rotation error was proposed, including the structure and correction algorithm of the technique. Simulations of the Walker 12/3/1 constellation indicate that the constellation's rotation error will cause the longitude of the ground user to have the same error. After applying the differential correction technique, the ground users will effectively correct this error. While the rotation error is less than 1'(equivalent to a 31 m horizontal error in the equator), the user's horizontal error is less than 1.5 m and the vertical error is less than 0.003 m after differential correcting.