关于北斗卫星导航系统的被动式定位算法比较研究

Study and Comparison of Several Passive Positioning Algorithms About "Beidou" Satellite Navigation System

我国北斗卫星导航系统空间卫星共有2或3颗,无法单独满足被动导航定位的要求．针对这种卫星稀少的情况提出了3种被动式定位算法: 2星定位算法、 3星3参数定位算法和3星4参数定位算法, 这些算法分别采用气压测高方法增加观测数据和采用数学模型描述接收机钟差的方法减少定位方程求解的未知数;探讨了北斗卫星导航系统备份星的可用性和对导航定位精度的贡献;还提出了准差分修正技术,提高了定位精度．实验证明, 3种算法都取得了100m以内的定位结果,可以满足一般用户定位需求．

There are only 2 or 3 satellites in the ＂Beidou＂ satellite navigation system, so it alone can not meet the demand of passive positioning algorithm. Three kinds of passive positioning algorithms about ＂Beidou＂ satellite navigation system are presented and compared： 2 satellites algorithm, 3 satellites 3 unknowns algorithm and 3 satellites 4 unknowns algorithm. The measurable parameters have been increased by adding height measurement and the unknowns have been decreased by modeling the receiver clock error with a 2 order polynomial. The availability of backup satellite of the ＂Beidou＂ navigation system is also studied. In addition, a technique named ＂quasi-differrential＂ correction scheme has been proposed. The positioning accuracy is improved by this technique. The experiment results show that all the three algorithms can achieve the accuracy of 100 m which can meet the common user＇s positioning demand.