Research On RAIM Technology Of GNSS Multi-constellation And Multiple Faults

With the sustainable development of global navigation satellite system(GNSS)and integrated networking,the accuracy of GNSS has been able to meet the needs of most fields.However,in some areas related to life safety,such as navigation and aviation,in addition to the accuracy requirements of satellite navigation system,integrity,as one of the important performance indicators of navigation system,also plays an important role in these areas.Receiver autonomous integrity monitoring(RAIM)is widely used in integrity monitoring because of its fast response to faults,low cost and wide coverage.The traditional RAIM method has a good recognition effect when there is only one fault satellite.However,with the expand of multi-constellation association positioning technique,rising number of satellites,and the rising chance of multiple kaput satellites in the meantime.The traditional RAIM method has poor recognition effect.Therefore,the research on RAIM method with multi constellation and multi fault has strong research significance and application value.The research of this subject will be carried out from the following aspects:1.The research background and significance of receiver autonomous integrity monitoring(RAIM)are summarized,and the research and current development of RAIM technology at the whole world in current years are summarized;the GNSS positioning theory and positioning principle are introduced,and the error sources of abnormal integrity are analyzed.2.The related concepts and classification of RAIM are summarized;the principle and process of RAIM algorithm are introduced;the usability of RAIM algorithm is studied;two traditional RAIM methods are deduced and compared by simulation.3.The implementation pattern and process of multi-constellation RAIM method are researched;the model of multi-constellation RAIM algorithm is established,and the traditional RAIM algorithm is extended to multi constellation for research,and a weighted least squares residual method is proposed.4.The advantages and disadvantages of RAIM algorithm in multi constellation and single constellation are analyzed,and the performance of RAIM algorithm in different constellation is compared.5.Through the study of the original grouping method,aiming at the shortcomings of the original method,an improved grouping RAIM method is proposed,and the simulation analysis of this RAIM method is carried out under the condition of multi constellation and single fault.6.Based on the research idea of random search RAIM algorithm,and combined with the satellite selection method,a RAIM method for optimizing satellite selection is proposed,and the simulation analysis is carried out under the conditions of multi constellation single fault and double fault respectively.