针对超宽带(ultra wide band,UWB)和微机电系统(micro electro mechanical system,MEMS)惯性测量单元(inertial measurement unit,IMU)紧组合滤波系统中,UWB测距信号存在较大的非视距(non line of sight,NLOS)误差及滤波系统异常,易造成噪声参数与真实噪声的概率分布严重不符,导致整个滤波系统发散甚至崩溃,严重影响紧组合系统性能的问题.提出UWB/MEMS IMU紧组合自适应扩展卡尔曼滤波算法(adaptive restimation extended Kalman filtering,AREKF),充分发挥惯性导航系统(inertial navigation system,INS)短时高精度特性,对UWB观测值进行异常探测,利用新息序列对观测噪声和预测状态误差协方差矩阵进行自适应调节,降低异常观测或NLOS误差的影响,有效防止滤波器过度收敛、发散、崩溃现象.动态行人实验结果表明,UWB/MEMS IMU紧组合AREKF方法N和E方向均方根(root mean square,RMS)优于 0.3 m,U方向RMS优于1.3 m,较UWB加权最小二乘法(weighted least squares,WLS)、UWB扩展卡尔曼滤波(extended Kalman filter,EKF)、UWB/MEMS IMU松组合EKF和UWB/MEMS IMU紧组合EKF有效提升了定位系统的精度、稳定性和可靠性.
Research on UWB/MEMS IMU tight combination adaptive robust Kalman filtering localization algorithm
In the ultra wide band(UWB)and micro electro mechanical system(MEMS)inertial measurement unit(IMU)tight-combination filtering system,the existence of large non line of sight(NLOS)errors in the UWB ranging signals and the anomalies in the filtering system are prone to cause serious discrepancies in the probability distributions of the noise parameter and the real noise,which leads to dispersion or even collapse of the entire filtering system,and seriously affects the performance of the tightly-combined system.The UWB/MEMS IMU tight combination adaptive robust extended Kalman filter(AREKF)method is proposed to give full play to the short-time high-precision characteristics of the INS to detect anomalies in the UWB observations,and utilize the innovation sequences to adaptively adjust the covariance matrices of the observation noise and the prediction state error,to reduce the impact of the anomalous observation or NLOS error,and effectively prevent the filter from over-convergence,dispersion,and collapse phenomena.Dynamic pedestrian experimental results show that the UWB/MEMS IMU tight combination AREKF method has RMS better than 0.3 m in the N and E directions and 1.3 m in the U direction,which effectively improves the accuracy,stability and reliability of the positioning system compared with the UWB WLS,the UWB EKF,the UWB/MEMS IMU loose combination EKF and the UWB/MEMS IMU tight combination EKF.
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