Research Of Different Grade INS And GNSS Integrated Navigation

This thesis focuses on the technologies of INS and GNSS integrated navigation,including research and verification of solution process and related algorithms of INS,GNSS and their integrated navigation respectively.It mainly analyzes the principle and implementation of INS aiding GNSS signal acquisition and tracking,and designs an INS sensors selection strategy based on the analysis.Besides,it designs an optimal bandwidth and evaluates the bandwidth improvement after different grade INS assisting GNSS signal tracking.Firstly,the thesis researches INS solution,analyzing an alignment algorithm based on the double epoch GNSS information,then the quaternion based attitudes solution,velocity solution and position solution process.Then it analyzes the GNSS velocity and position solution process using pseudorange information,deducing algorithm of INS and GNSS integration navigation,then verifying the feasibility of the algorithm and presenting the performance of algorithm by using field test data.Then,the principle of INS aiding GNSS signal acquisition and index to evaluate performance of GNSS signal acquisition are presented in the thesis.INS error modeling and velocity error assessment are showed later.Then performance evaluation of different INS aiding GNSS signal acquisition is given according to different carrier dynamic situations and an INS selection strategy based on it is designed:there is no need to use INS when the carrier is under low dynamic situation.For middle dynamic carriers,it only requires automotive grade INS within short interval and tactical and navigation grade INS within long period of time.For high dynamic carriers,it is feasible to utilize consumer and automotive grade INS during short interval,but requires tactical and navigation grade INS in long period of time.Besides,the detection probability is improved and acquisition time highly compressed after INS assistance,the detection probability increased at least 20%under different dynamics,the acquisition time decreased more than 60%,and can be decreased 99%when the INS velocity error is small?5m/s?.Later,the principle of INS aiding GNSS signal tracking is illustrated and contradiction between high dynamic and increasing loop error is showed.Utilizing INS in GNSS signal tracking can solve this contradiction efficiently.Then the thesis introduces the loop design and optimal bandwidth design of the INS aided PLL.After analyzing different INS assisting GNSS signal tracking then it comes to the conclusion:when the C/N₀ is more the 20dB-Hz,tactical INS can condensed the loop bandwidth up to 68.69%compared to traditional loop,navigation grade INS can condense the bandwidth up to 97.84%.However,the automotive and consumer grade INS can not effectively help the bandwidth reduction for their worse error characteristics.Finally,it concludes the work of this thesis and puts forward the question worth researching in the future according to the restraints and shortcomings in the current research.This thesis mainly assesses the performance of different INS aiding GNSS signal acquisition and tracking,then comes up with an INS sensor selection strategy when aiding the GNSS signal acquisition.It also designs an optimal bandwidth based on the INS assisted PLL.In all,it provides certain guidance in the realization of INS/GNSS deeply integration system.