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为统一北斗三类卫星的历书拟合算法,提出基于第二类无奇点根数进行历书参数设计的方法,设计了以倾角向量变率作为摄动参数的历书参数模型,并给出新的历书模型的用户使用算法。利用覆盖2013年全年的实际在轨卫星的数值轨道进行了历书拟合试验。结果表明,地球静止轨道(GEO)和倾斜地球同步轨道(IGSO)卫星的拟合位置误差为2~4 km,拟合用户距离误差(URE)约为1 km,中圆地球轨道(MEO)卫星的拟合位置误差为1~2 km,拟合URE约为500 m。通过分析6个轨道根数和2个摄动参数全年的变化范围,对新历书模型进行量化单位和占用比特位的通信接口设计,定量分析量化单位对历书表达精度的影响。结果表明,参数截断后对位置误差的影响小于50 m,对URE误差的影响小于5 m。因此,历书量化误差对信号捕获以及首次定位时间带来的影响可以忽略不计。
In order to unify the almanac fit algorithm of the BeiDou satellites, a method of almanac parameter design based on the second kind of nonsingular root number is put forward. The almanac parameter model is designed with the change of dip vector as the perturbation parameter, Almanac model user usage algorithm. Almanac simulations were conducted using numerical orbits that cover actual orbiting satellites in 2013. The results show that the fitted error of GEO and IGSO satellites is 2 ~ 4 km and the fitted user error (URE) is about 1 km. The mean orbital orbit of a medium Earth Orbit (MEO) satellite The fitting position error is 1 ~ 2 km and the fitting URE is about 500 m. By analyzing the range of 6 orbits and 2 perturbation parameters throughout the year, this paper designs the communication interface between the New Calendar Model and the quantification unit and the occupied bit, and quantitatively analyzes the influence of the quantization unit on the almanac expression accuracy. The results show that the influence of position truncation on the position error is less than 50 m and the influence on URE error is less than 5 m. Therefore, the impact of almanac quantification errors on signal acquisition and first-time positioning is negligible.