Research And Implementation Of Multi-modal GNSS Navigation And Position Information Processing System

With the development of navigation technology,especially the rapid deployment and improvement of each global navigation satellite system,the combination of various navigation systems has become a hot spot and trend.At the same time,the demand for high performance navigation in various fields is also increasing,the single navigation system is usually difficult to meet the needs of navigation and positioning.In this thesis,based on the GNSS multi-mode combined positioning and INS/GNSS combination navigation,we studies the combination of positioning information processing between multi-navigation systems.The main work of this thesis is divided into the following parts:1.Study the pretreatment process and method of GNSS and INS data.The parameter characteristics of GNSS system are analyzed,and the unity of space coordinate and time system is realized.Then,the GNSS data quality is analyzed from two aspects of the navigation signal power spectrum and the carrier to noise ratio,and the data is verified by real data,which can provide some prior information for the realization of GNSS multi-mode combination positioning.This thesis analyzes the principle of INS algorithm,and puts forward the solution to the inconsistency of the speed in filtering fusion positioning.2.The process and method of multi-mode combined navigation of GNSS are researched.Firstly,this thesis describes the GNSS signal processing,satellite position speed calculation,user location calculation.The problem of satellite information optimization is studied,and a new method is proposed,which takes into consideration the quality of satellite signal,the error of observation and the elevation angle.Analysis of the GNSS multi-mode combined solution principle,established the Kalman filter model of multi-mode combined,in the actual calculation of the measured values at each epoch do serial processing,and testing the validity of measurements.Based on the observation data of IGS,the corresponding experimental verification is done.3.GNSS and INS system combination techniques and methods.Based on the small angle error assumption,the INS error model is educed,respectively established the spatial arm error model and time synchronization error model,then used them as states of integrated navigation filter.To analyze the GNSS/INS loose couple information processing,a combined model of position/velocity deviation is established.Based on Kalman filter,the GNSS/INS loose couple is done.To analyze the processing method of GNSS/INS tight integrated,the state equation and measurement equation is established.Based on the unscented Kalman filter,the GNSS/INS tight couple is done.Analysis the advantages and disadvantages of the loose and tight couple.For the deterioration of the loose couple system performance owing to lack of star in the city valley,an improved mode of combination is proposed.The INS position is used in the GNSS solution,then the derivation,analysis and simulation verification has been completed.4.Based on the analysis of GNSS multi-mode combination positioning and INS/GNSS positioning,this thesis designs a semi-physical realization platform to verify related theoretical methods.The multi-mode signal of GPS/BDS is collected by the GNSS IF signal sample equipment,and the multi-mode combined processing software is designed to capture and track the real data.Signal tracking stability,and the positioning accuracy up to 4.5m(95%CEP).Secondly,using IMU and GNSS equipment to collect the data of satellite and INS,then the GNSS and INS loose and tight integrated navigation are realized.The experiments show that the performance of the two integrated is quite similar in the ordinary vehicle environment.Aiming at the lack of star in the city valley,the comparison between the improved combination and tight integrated navigation shows that the performance of the improved combination is similar with tight integrated when the star is lacking.