基于广播星历参数的卫星自主导航算法

Satellite autonomous navigation algorithm analysis based on broadcast ephemeris parameters

在自主导航中,目前星载处理及传输能力还不足以支持传统模式下全星座集中式动力学定轨算法.为了尝试将集中式应用于星载处理的可能性.本文提出了一种以卫星长期预报星历为基础,以广播星历参数为变量,由观测数据直接获取广播星历修正结果的集中式运动学定轨方法.该方法在地固系下进行轨道计算,无需上注EOP参数,定轨结果无误差累积.并且该方法将轨道确定与星历拟合合并为一步进行,既省略了轨道积分计算,又直接获取广播星历,可有效降低处理的计算量.试验结果表明该方法在4 h弧段内可将数据采样间隔放宽至20 min,有效减低了自主导航对星间链路测量频度及数据处理频度的要求.在现有卫星轨道60 d长期预报精度条件下,可满足URE 1 m、位置3 m的定轨精度.为集中式定轨方法应用于星载处理提供了可能.

At present, the satellite on-board processing and transmission capacity of autonomous navigation is not enough to support the traditional centralized dynamic navigation algorithm. In order to augment the possibility of centralized onboard processing, this paper puts forward a centralized kinematics orbit determination method which is based on the long term broadcast ephemeris. This method directly calculates broadcast ephemeris corrections using inter-satellite observations, and executes in earth fixed coordinate without EOP parameter supports. The orbit results have no error accumulation. Compared with traditional processing mode, the orbit determination and ephemeris fitting steps are fitted into one step, and the orbital integral is omitted, so the amount of calculation could be effectively reduced. The experimental results show that the data sampling interval can be broadened to 20 min in a 4 h arc. This result could effectively reduce the requirements of satellite measurement and data processing frequency in autonomous navigation. Based on the current precision of 60 d long term orbit forecasting, this method can meet the orbit determination precision of URE 1 m and three-dimensional position 3 m. So it offers the possibility to achieve the on-board centralized autonomous navigation processing.