基于UKF的GPS定位算法

GPS Positioning Algorithm Based on UKF

针对EKF通过局部线性化方法处理非线性问题可能产生的精度下降问题,提出了用UKF进行GPS定位解算的方法。介绍了UKF方法的原理,分析了GPS伪距方程的线性化近似误差和定位精度的关系,并讨论了利用UKF进行定位解算的有效性。采用"当前"模型,利用伪距和多普勒观测量进行定位解算。利用Spirent GPS模拟器和NovAtel差分定位系统及NovAtel接收机分别进行了仿真实验和现场实验。结果表明,当滤波器状态初值误差较大时,UKF与EKF相比有明显的优势。

The extended Kalman filter deals with nonlinear problems using Taylor series expansion,leading to degraded performance.The UKF is adopted for GPS positioning in this paper.After formulating the UKF algorithm,a relationship between the linearized approximation error of GPS pseudorange equation and the positioning error is analyzed.The validity of UKF in GPS positioning is discussed.Pseudorange and Doppler shift measurements are used and the current statistics model is utilized in data processing.Simulation and field experiment are carried out by employing Spirent GPS simulator and NovAtel differential positioning system as well as NovAtel receiver,respectively.The results show that UKF has better performance than EKF when there are large errors in initial state values of the system.