Research On INS/GNSS/CNS Integrated Navigation System Of High Altitude Aircraft

High altitude aircraft with its high mobility characteristics has been widely studied and applied in the field of the military and civilian aircraft at home and abroad.Taking into account its special military applications,high altitude aircraft can have high accuracy navigation ability has become the key of the research.To improve the accuracy of high altitude aircraft navigation systems effectively,the method of constructing the integrated navigation system that each of them with advantages came into being.On this basis of the above,this paper analyzes the working principle and characteristics of inertial navigation,global navigation satellite and astronomy navigation systems,and carries on the key research and analysis on the problem and corresponding solutions of the INS/GNSS/CNS combined navigation system applied to the high altitude aircraft.The main research work is as follows:1)This paper deduces the model structure of INS/GNSS/INS integrated navigation system,including INS error equation,GNSS dynamic positioning principle,CNS attitude determination principle and construction of the integrated navigation system.And in view of the advantages of each navigation subsystem construct position,velocity and attitude navigation system.2)Give research on the measurement asynchronous issue which exists in information fusion of INS/GNSS/CNS multi-sensor integrated navigation system,and solved this problem using asynchronous data fusion.Then analyze the navigation calculating error bring from GNSS measurements lagging,and solve this problem using lag compensation with the standard of INS measured output.Finally give INS/GNSS/CNS integrated navigation system centralized asynchronous fusion algorithm with lag compensation.The simulation also shows that the algorithm can solve synchronized of the measurement in the integrated navigation system and lagging impact by GNSS.3)In order to improve the INS/GNSS/CNS integrated navigation system fault-tolerant performance and reduce the navigation system filtering decoding complexity improving the real-time performance of navigation calculating,distributed federal filter is proposed to filtering calculate.And also,the information distribution method in the filtering algorithm directly affects the filtering precision of navigation system.Considering the conventional information average allocation algorithm can't reflect real-time calculating precision of each filter in the filtering process,this paper proposes a kind of dynamic allocation vector information of federated filtering algorithm.This algorithm combining with filter each moment of navigation subsystem observable degree and precision of each filter to filter can effectively solve the problem that brings from conventional information distribution method.Finally the simulation shows that navigation calculating accuracy has improved greatly compared with conventional federal filtering.4)Considering the INS/GNSS/CNS integrated navigation system navigation filtering model error,this paper give research on the state noise model uncertainty and the observation model problems.Aiming at state noise model uncertainty,this paper uses the Sage-Husa adaptive filtering algorithm for online adjustment.Aiming at the observation model problems,this paper puts forward the idea of interactive multiple model,constructing observation normal model and observation model to solve this problem.the simulation shows that adaptive interacting multiple model algorithm can effectively control the effects of model uncertainty in the INS/GNSS/CNS integrated navigation system.