Research On GNSS Autonomous Integrity Monitoring Methods

With the progress of human civilization, Global Navigation Satellite System has become an important space infrastructure applied to land, sea and air travel. As the key indicator of navigation system, positioning accuracy has meet the requirements of most scenes. However the development of GNSS integrity monitoring technology lags behind its positioning technology. When there exists a failure in navigation system, it will pose a serious threat to the safety of the users if integrity monitoring system could not alarm it timely. So, research on GNSS integrity monitoring method has important practical significance from a security point of view.Focused on GNSS autonomous integrity monitoring, this thesis researches deeply on satellite’s integrity monitoring methods and receiver autonomous integrity monitoring methods. The main work includes:1. Research on Satellite Autonomous Integrity Monitoring algorithm based on Inter-Satellite measurement and Chi-square test. The measurement error model based on Inter-Satellite is described in detail. A test statistics for SAIM is constructed and the expression and calculating method of Minimal Detectable Bias is demonstrated. The simulation experiments shows that the algorithm has a good monitoring performance under Gaussian model, and the detection performance will enhance with the increase of number Inter-Satellite.2. An orbit integrity monitoring algorithm based on control chart is proposed. The shortage of integrity monitoring method by comparing orbit integration accuracy of different satellite is pointed out. On this basis, theory of Shewhart control chart and CUSUM control chart are given. Simulation of two control charts in different sizes and velocity of migration are compared, and monitoring result based on IGU and IGS is given.3. Research on Receiver Autonomous Integrity Monitoring methods in single and multiple navigation system. The deficiency of performance of traditional “Snapshot” RAIM methods in single system is pointed out. On this basis, principle of RAIM in GPS+Galileo integrated navigation satellite system is proposed, and procedure of fault detection and identification is described. After simulating constellation of GPS and Galileo, this thesis analyzed RAIM performance of integrated system. The result shows that GPS+Galileo integrated navigation satellite system has a higher performance in geometric dilution of precision, fault detection and identification.4. RAIM simulation software is developed. The architecture and function of the software is designed. The process of software is elaborated, and interface of software is presented. At last, this thesis tested the feasibility of software.