基于星间测量的卫星星座自主导航算法

自主导航能力是新一代导航星座的重要特性,利用卫星星间相对测量实现星座自主导航,是实现导航星座自主运行的基础.基于相对测量的导航卫星自主导航问题,将导致测量方程和状态方程的高度非线性,对导航算法提出了新的要求.在总结前人工作的基础上,提出了一种星载导航算法方案:利用三颗卫星之间的相对矢量在惯性空间的投影作为测量量,利用高精度星载轨道预报器作为系统的状态方程,使用SRUKF(Square Root Unscented Kalman Filter)滤波算法同时对三颗卫星的位置进行估计.仿真结果表明,该方案具有可行性,并且当轨道预报器的精度较高时有可能在100d内实现5m的导航精度.

Autonomous orbit determination algorithm for constellation from relative position measurements

The ability of autonomous navigation is one of the key features supporting autonomous operation of the new generation navigation constellations.Autonomous navigation based on relative position measurements among satellites can be described as a high order nonlinear estimation problem,solving such a problem will be a big challenge for onboard computers.A new solution was introduced to improve the computational efficiency of autonomous navigation: an autonomous navigation constellation made up with three satellites was designed to reduce the difficulties in algorithm implementation.The measurements are relative satellite positions in inertial space.Square root version unscented Kalman filter(SRUKF) was introduced to deal with the nonlinearity of the relative measurements and orbit dynamics model.A new autonomous navigation algorithm was designed so that all the three satellites' positions can be determined at the same time.Simulation results show that an accuracy requirement of 5 m user range error(URE) within 100 days can be met.