Research On Fault Tolerant And Reconfiguration Algorithm For Redundant Navigation System

Navigation system is one of the most key parts for unmanned aerial vehicle(UAV). Its accuracy and reliability is very important to the execution of control commands and the safety of flight. So generally, the UAVs with high requirements of reliability are configured redundant navigation system. But in redundant navigation system, a navigation signal maybe exist multiple signal sources. In order to make the best use of the different source signals and achieve high reliability and realize the goal of fault tolerance, we must have a management to deal with them. Therefore, the fault-tolerant and reconfiguration algorithm of redundant navigation system is one of the key technologies of UAV system. This paper mainly includes the following aspects of the research work in this area:At first, introduce the theories relating to the integrated navigation system whose core is SINS/GNSS/ADS. Base on the Studying of each sub navigation system and Modeling for SINS and GNSS, build the simulation model of the SINS/GNSS/ADS integrated navigation system and carry out the simulation of the whole system.The second, aiming at the problem of high cost of hardware redundancy, a navigation solution based on analytic redundancy is proposed. Based on the kinematic equation of the aircraft, the analytical redundancy technique is used to construct the navigation sensor signal to join the calculation navigation parameters and build a redundant parallel to the real navigation equipment. The analytic signals are involved in fault tolerant and reconfiguration management with signals from hardware devices, which not only provides reference basis for fault detection, but also can extend the working time of the system indirectly.Third, the fault tolerant and reconstruction algorithm used in navigation system is studied. Analyze fault tolerant reconfiguration algorithm from fault detection and the vote of redundant signal two directions. On the basis of previous studies, an improved fault tolerance and reconfiguration algorithm based on the parity detection method and the statistical characteristics of navigation signal is proposed. The improved method make use of the statistical information of the difference between sensor signals, combining self-detection and mutual-detection to achieve the purpose of fault detection, and isolating the fault signal. Then use the improved method to complete the voting and reconstruction.At last, combining hardware redundancy and analyze redundancy, designed the architecture of the redundant navigation system. And the redundant navigation signals are managed by the improved fault tolerant and reconstruction algorithm. Finally, use SIMULINK to build its model and carry out the Simulation of the system.The final results show that the modeling and Simulation of redundant navigation system in this paper has good capability of fault tolerance and reconfiguration. Fault tolerant and reconfigurable management algorithms can detect the once-fault and twice-fault of the Treble-Redundancy system. At the same time, the improved redundant voting method can also greatly force the reconstruction signal approaching the true signal, enhancing the safety and reliability of the whole system.