无源北斗/惯导组合导航算法研究

针对北斗卫导/惯导组合导航系统设计组合导航卡尔曼滤波定位算法,并对组合导航算法的可观性进行了分析,提出了引入伪距率和前后滤波伪距之差作为观测量改善组合导航系统的可观测性。基于高稳定度的用户时钟,通过仿真验证了伪距率和前后滤波伪距之差观测量都能提供伪距不能提供的额外观测信息,都可以将钟差由不可估计变为可估计,改善组合系统的稳定性,并且提高丢星时的滤波定位精度。因此,在北斗/惯导组合导航系统中引入伪距率或前后滤波伪距之差做观测量是必要而可行的。

Study of passive "BeiDou" integrated navigation algorithm

A Kalman filter positioning algorithm applied in "BeiDou" satellite and INS integrated navigation system(BD/INS) is proposed.Its observability is analyzed,based on which the pseudo-range rate and the difference of pseudo-ranges measured between fore-filter and aft-filter(DPR) is proposed as the observations.Then,on the basis of the high-stability clock,it is shown by simulation that using pseudo-range rate and the DPR as observations makes the state clock-difference estimable and improves the stability of the integrated navigation system,especially,it improves the positioning precision of the BD/INS system when the satellites in sight are less than two.So,using pseudo-range rate or the DPR as observations in BD/ INS integrated navigation system is necessary and feasible.