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传统的GNSS/IMU(global navigation satellitesystem/inertial measurement unit)组合导航系统采用固定速率更新策略,平等地对待每一个观测量。因而在受到突发干扰情况下,精度恶化的观测量可能影响到更新后的组合导航结果的精度。该文提出一个双门限的观测量丢弃策略,它同时监控估计量的误差累计程度和观测量的恶化程度。当估计量误差很低或者观测量恶化很严重时,把观测量丢弃掉,使组合导航系统工作在INS(inertial navigation system)单独导航模式。真实的外场试验结合仿真干扰表明:含观测量丢弃策略的扩展Kalman滤波(EKF)跟传统的固定更新速率EKF相比,在干扰条件下具有更低的误差。
The traditional GNSS / IMU integrated navigation system uses a fixed rate update strategy to treat each observation equally. Therefore, in the case of sudden interference, the observation of deteriorating accuracy may affect the accuracy of the updated combined navigation results. This paper presents a double-threshold observation drop strategy that monitors both the cumulative error of observations and the deterioration of observations. When the error of estimation is very low or the deterioration of observation is very serious, the observation is discarded and the integrated navigation system is operated in inertial navigation system (INS) navigation mode. The real field experiment combined with simulation interference shows that Extended Kalman Filter (EKF) with observed discard strategy has lower error under interference condition than the traditional fixed update rate EKF.