Research On The Theory And Method Of Multi-frequency GNSS/INS Integrated System Precise Positioning And Orientation

In the future,most of the Global Navigation Satellite System(GNSS)will transmitte triple even multiply frequencies signals,which could provide more observables and develop the precision and reliability of the navigation and positioning.In recent years,the research on multifrequency is at the leading edge of the GNSS.However,the methodology about utilizing the multifrequency for GNSS/INS(Inertial navigation system)integrated system has not been fully investigated.Thus,the relevant theory and method of the multi-frequency GNSS/INS integrated system are deeply researched in this thesis,the main works and creations are as follows:1.A triple-frequency differential GNSS/INS tightly coupled integration model is presented,which fully benefits from the redundant observables and the fast speed of the triple-frequency integer ambiguity resolution(TCAR).The new model is optimized on model architecture,observation utilizing and computing efficiency.Besides,the robustly adaptive Kalman filter is applied and the dual-factor weight function and adaptive factor fit for the new model are constructed.The research of this paper demonstrates that the new model has the better computing efficiency than the traditional model,while also achieves the same precision level.2.The method of inertial aided three carrier ambiguity resolution(iTCAR)is proposed.With the advantages of TCAR and the assistant of the INS,the iTCAR is fast and reliable in complex kinematic condition.Three vehicle integrated navigation tests are performed to analyze the success ratio of different observation condition,the success ratio of the EWL when using different pseudo range source.And the performance of iTCAR is demonstrated that more reliable when compared to the traditional TCAR.3.The new method of inertial aided multi-frequency ambiguity resolution(IMAR)is proposed.The IMAR utilizes the combined observations which are characterized by long wavelength,low carrier-phase noise and ionospheric delay.The mathematical model of the IMAR is derived.The impacts of the carrier-phase noise,ionospheric delay and INS predicted position error on the ambiguity resolution success ratio of combined observation are analyzed through probabilistic method,based on which the selection strategy of the combinations are proposed.The combinations(0,-1,1),(1,4,-5)and(4,-2,-3)are selected to resolve the original ambiguity.Vehicular navigation is conducted and the new method perform well when the signals of the satellites are normal,partial blocked,and complete blocked.4.The new method of inertial aided multi-frequency linear combinations for cycle slip detection and repair are proposed.Benefits from the high precision INS predicted geometry information and the characteristic of combinations,the new method can detect and fix small cycle slip reliability.The probabilities of missing detection and false alarm are derived.And the impacts of carrier-phase noise and INS predicted position error on the precision of combine cycle slip detection are investigated.Based on above investigation,the combinations(0,-1,1),(1,3,-4),(-3,4,0)are selected to detect and repair cycle-slip cooperatively.A land vehicle test data is utilized to demonstrate,and result show that the new method can detect and fix the cycle slip when simulative cycle on each epoch,BDS satellite signals partial outage and BDS satellite signals complete outage.5.The comprehensive research about the effects of multi-frequency,BDS/GPS integrated,INS aiding from the tightly-coupled,multi-frequency on the Ratio value,ADOP,float ambiguity error,AR(Ambiguity resolution)success ratio,AR correct ratio is made in this paper.The triplefrequency BDS/GPS/INS tightly-coupled integration model is built first.The ADOP closed-form expression of the multi-frequency is derived,based on which the impact of the multi-frequency on the ADOP is analyzed and demonstrated by test data.The experimental results show that the multifrequency,INS aiding,BDS/GPS integrated develop the performance of the LAMBDA for the kinematic real-time positioning.The investigation and conclusion are helpful for the surveying user choosing the signal frequency,navigation system and INS aiding.