【作者】 李倩；

【导师】 战兴群；

【作者基本信息】 上海交通大学 ， 导航制导与控制， 2010， 硕士

【摘要】 全球定位导航系统(GPS)可以提供高精度的导航定位信息,但是由于外部环境因素影响导致GPS信号失效时,GPS接收机不能正常工作。捷联惯性导航系统(SINS)是一种自主式导航方式,不受外界环境影响,但是捷联惯性导航系统由于自身工作原理的原因,导致导航定位误差积累,所以捷联惯性导航系统不能长时间单独工作。GPS/INS组合导航系统很好的解决了这个问题,它弥补了惯性导航误差积累的问题,同时在GPS信号失效的短暂阶段可以由惯性导航单独工作继续连续的提供导航定位结果。本文首先对捷联惯性导航系统和全球定位导航系统分别进行了详细的分析,进而对GPS/INS组合导航系统相关关键技术进行了深入研究。其中,重点讨论了组合导航系统中的时间同步问题,分析了时间偏差对滤波结果的影响,并基于FPGA设计完成了GPS/INS时间同步系统;同时,对GPS/INS组合导航系统中的松组合算法和紧组合算法分别进行了仿真验证,特别是针对紧组合算法,验证了紧组合导航系统在卫星数少于4颗时的工作情况;最后,本文在工程背景下,基于MEMS级别的IMU实现了GPS/INS松组合导航系统,并针对地面车辆的运动特点,引入了车辆的不完全约束条件。论文中,通过半物理仿真实验验证了所设计的基于FPGA的GPS/INS时间同步系统的有效性,解决了GPS/INS组合导航系统中时间偏差对导航结果影响的问题;在Matlab环境中,对紧组合导航算法进行了着重研究,通过仿真结果验证了在可见卫星数少于4颗时,紧组合导航系统仍然可以正常工作,并通过比较仿真结果,定量分析了可见卫星数目对导航定位精度的影响;最后,通过户外跑车实验,验证了本文中所实现的GPS/INS松组合导航系统的可行性,进而有效的证明了本文引入的车辆的不完全约束条件的有效性,成功地解决了GPS信号失效阶段,低精度惯性导航设备单独工作时误差快速积累的问题。更多还原

【Abstract】 Global Positioning System (GPS) provides the high accuracy of positioning output under normal environment, but the GPS receiver can’t work well when the signal is attenuated under the complex environment. The Strapdown Inertial Navigation System (SINS) has the advantage of being independent of external electromagnetic signals, and it can operate in any environment. But the SINS system suffers from time-dependent error growth which causes a drift in the solution for the work principle. The integration of GPS and SINS can overcome the defects of SINS or GPS standalone systems, and benefits from the complementary characteristics of the two systems. When the GPS signal is outage, the SINS can work alone till the GPS signal is gotten back to provide the continuous positioning output.Based on a detailed analysis of the SINS and the GPS, the crucial technology of GPS/INS is discussed in detail, which includes the time synchronization between the data from GPS receiver and IMU and the integration algorithm. For reducing the influence of time synchronization error on the data fusion performance of hybrid filter, some equations are derived to determine the influence of time synchronization error on the Kalman filter and a new solution for time synchronization based on a Field Programmable Gate Array (FPGA) is proposed. The loose integration and the tight integration algorithm is simulated to approve the validity, specially the validity of tight integration algorithm of GPS/INS is discussed under the environment of fewer than four satellites. In the context of engineering, a loose GPS/INS integration scheme is implemented based on MEMS IMU, and the non-holonomic constraints for land vehicle applications is introduced to keep the position accuracy within bounds when the GPS is not available. The result of the field test demonstrated the validity of the system.更多还原