Application Of Information Fusion Technology In GPS/INS Combined Guidance System

The purpose of this paper is to reduce the guidance tool error(navigation system error)of GPS/INS combined guidance system using information fusion technology.This paper focus on how to improve the accuracy and reliability of GPS/INS integrated navigation system and provide accurate navigation parameters(including speed,location and attitude information)to generate accurate guidance instructions,thus improve the guidance accuracy of precision-guided weapons.Main research contents and innovations in this paper are as follows:(1)The INS and GPS navigation parameter calculating method is determined.The inertial navigation error equation,inertial sensor error equation and GPS receiver error equation are also established.The INS and GPS navigation simulation under specific trajectory is completed.(2)The strong tracking Kalman filter algorithm is improved and applied to the GPS/INS tightly coupled navigation system.The residual observations are used to adjust the filter gain matrix at the same time,the strong tracking filtering algorithm is improved by adding time-varying noise estimator.It solves the problem of filter estimation deviation caused by the inaccuracy of the noise model or the uncertain change of the noise model.It effectively enhances the system's accuracy and anti-interference ability.(3)The wavelet analysis technology was applied to detection the fault in the GPS/INS combined system.Wavelet analysis shows good detail processing characteristics in the time-frequency domain.The GPS receiver's measurable data or navigation location data are taken as processing objects,and multi-scale analysis is carried out.The outliers are identified to identify the faults.The method has the characteristics of high efficiency,sensitivity,simplicity and intuition,and easy to be realized in engineering.It effectively solves the problem that the detection method based on Kalman filter relies heavily on accurate mathematical model,the failure inspection is not timely,and the calculation of is increased.(4)The GPS/INS fault-tolerant combined guidance system is designed and used for the midcourse guidance of the cruise missile.For the GPS / INS loosely coupled navigation system,firstly,using the “variance upper bound” technology to solve the problem of position and velocity measurement of GPS receiver are related.Then,a federal fault-tolerant Kalman filter is used to fuse the navigation information to detect and isolate the GPS fault.Finally,a three-tier fault detection structure is adopted to achieve fault-tolerant design of the whole system.The guidance accuracy is analyzed by combined navigation error,speed error spread domain and position error spread domain at the end point of middle guidance.Simulation results show that cruise missiles using GPS / INS fault-tolerant composite guidance can effectively reduce the velocity and position deviation at the end point of middle guidance,which caused by the guidance tool error.Guidance systems can ensure high guidance accuracy through their fault-tolerant performance in the event of GPS receiver failure.