导航星座自主星历更新技术

自主星历更新是导航星座自主导航的关键技术之一,包括卫星轨道精确确定和轨道短时预报两个方面的内容.相比之下,卫星轨道短时外推预报容易实现.因而,本文在系统地论述导航星座自主导航信息处理流程的基础上,重点提出一整套由星间双向伪距和测量方程、卫星受摄轨道系统状态方程、以及协方差匹配自适应Kalman滤波组成的卫星自主轨道确定算法.仿真结果表明：利用星载Kalman滤波器处理星间双向测量数据,卫星自主轨道确定精度和用户测距精度可以分别达到5.40m、1.86m,能够满足用户高精度导航应用需求.初步证明导航星座自主导航信息处理流程及其星历更新算法的合理性和可行性.

An Autonomously Updated Ephemeris Technique for Navigation Constellation

The autonomous updating of the navigation ephemeris is one of the key techniques for the autonomous navigation constellation. It includes two studying aspects, the accurate orbit determination and the short-term orbit prediction. Comparing to the former, the latter could be fulfilled easily. Therefore, on the basis of systematically describing the data processing flow for the autonomous navigation constellation, an algorithm autonomously determining the satellite orbits was presented perfectly as a core part in this paper. It consists of the measurement equations with the inter-satellite pseudo-ranges sum, the system state equations with the orbit perturbation and the adaptive Kalman filtering with the covarlance estimation. Finally, it can be shown from the simulated results that by processing the inter-satellite measurement data based on the on-board Kalman filter, the accuracy of the autonomous orbit determination attains to 5.40m, and the user ranging accuracy to 1.86m. Obviously, it can satisfy the requirement for the highly accurate navigation. The feasibility and rationality of the autonomously updated ephemeris and data processing flow for the autonomous navigation constellation is demonstrated preliminarily.