摘要
在一些恶劣环境下,定位终端无法观测到4颗及以上GPS卫星来确定终端位置,无线网络中的TDOA定位方法也没有足够数目的TDOA观测量来实现定位。文中利用最速下降算法融合在这一条件下的GPS伪距和TDOA观测量,在两种定位方法都无法单独定位时实现了定位。算法先将GPS伪距观测方程做单差运算、消除钟差,然后与TDOA双曲线方程组合,定义了加权残差平方和目标函数。目标函数的最优解由最速下降算法获得。文中将该算法与GPS/TDOA泰勒级数-最小二乘混合定位算法作了对比,实地NLOS条件下所得的实验结果表明在相同条件下最速下降混合定位算法比泰勒级数-最小二乘混合定位算法定位精度高;在采用最速下降混合定位算法时,GPS卫星数越多,TDOA观测量数目越多定位精度越高。在3颗卫星和3个基站的混合定位情况下,最速下降混合定位算法所得结果的平均误差为17.64 m,可以满足一般导航系统的需要。
Under certain bad conditions,the number of observed GPS satellites is less than 4 for location determination and TDOA location method in cellular networks can not get enough TDOA measurements to position the mobile.In this paper,steepest decent method is used to fuse GPS pseudo-range and TDOA observations and resolve the problem;and the method can calculate the location even when neither of the two methods has positioning ability.The algorithm first differentiates between GPS pseudo-range equations to eliminate the constant terminal clock bias and gets GPS hyperbola equations.Then the GPS hyperbola equations are combined with TDOA hyperbola equations from cellular networks to define the weighted residual objective function.The optimal solution of the objective function is obtained with steepest decent method.The proposed algorithm is compared with Taylor-least squares hybrid location algorithm in field experiments.Results show that under the same condition,the proposed hybrid algorithm can achieve higher accuracy.The algorithm can perform better with more observations of GPS pseudo-range and TDOA.With 3 GPS pseudo-ranges and 3 TDOA,using the steepest decent hybrid algorithm,the average error is 17.64 m,which meets the requirements of general navigation systems.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2011年第7期1500-1506,共7页
Chinese Journal of Scientific Instrument
基金
"十一五"国家科技支撑计划资助项目(No.2008BAJ11B01
No.2008BAJ11B02)资助
