单脉冲星自主导航系统可观测性分析

研究了基于单脉冲星的卫星自主导航系统中的重要理论问题——可观测性问题.建立了系统的状态方程和量测方程,根据扩展卡尔曼滤波对系统模型进行线性化处理的特点，采用分段式定常系统(PWCS)的可观测性分析方法分析系统的可观测性,经理论分析可知，系统的可观测矩阵接近奇异，可观测性较差.仿真结果表明：利用单颗脉冲星的量测信息能够修正卫星轨道动力学预报的位置和速度估计值，在短期内可将其误差控制在一定的范围内,但是很难实现长期的卫星自主轨道保持.

Observability Analysis of Satellite Autonomous Navigation System Using Single Pulsar

Observability of the single pulsar-based satellite autonomous navigation system is studied. The state equation and measurement equation of the system are presented. According to the characteristics of linearization of the extended Kalman filter, the observability analysis of piece-wise constant system (PWCS) is carried out to study the system observability. In the theoretical analysis, the observable matrix of this system is nearly singular, and the system is completely unobservable. It is demonstrated by simulation that, with measurements from only one pulsar, the estimated position and velocity propagated by satellite dynamics can be improved.Errors in position and velocity can be kept within certain limits in short time; but the satellite orbit cannot be estimated accurately over long time.