Research On The Key Technology Of GNSS/INS High Precision Fusion Positioning

With the development of society and technology,navigation positioning is no longer limited to the military field,but also plays an important role in the civil field.In order to give full play to the advantages of various navigation systems and overcome respective shortcomings,the integrated navigation has become a research hotspot in the field of navigation and positioning.Only a single Global Navigation Satellite System(GNSS)or Inertial navigation system(INS)can't meet people's requirements for accuracy and reliability.The GNSS can provide high-precision three-dimensional position information for moving carriers.The positioning error of GNSS can't accumulate over time,but GNSS is shielded or interfered by the signal.The INS can use inertial components(gyroscope and accelerometer,etc.)to calculate the navigation information of position,velocity and attitude.Inertial navigation system has autonomous navigation capability and strong anti-interference ability.The INS solution is based on the integration principle,so it is difficult to get rid of the limitation of error accumulation over time when obtaining the navigation information of the moving carrier.GNSS and INS are the research hotspot in the field of integrated navigation because of their good complementary characteristics.The GNSS/INS system can obtain 3D position,velocity and attitude information with better reliability,higher accuracy and faster data update rate.In the case of GNSS signal shielding or loss of lock,the GNSS/INS integrated navigation system can only use INS for navigation.However,the system accuracy of integrated navigation will be reduced due to the accumulation of INS navigation errors.When GNSS is shielded by signal and INS accumulated error is large,the system accuracy is lower than that of GNSS with good signal and small INS error,so it is difficult to realize unified positioning under indoor,outdoor and signal shielding conditions.Therefore,how to maintain the high accuracy and reliability of integrated navigation system for a long time remains to be studied.According to the different error characteristics of GNSS and INS in different stages of time domain,the INS cumulative error model in time-domain and the GNSS error model in time-domain are established.This paper studies GNSS/INS high-precision information fusion,including INS error analysis and processing,the error models of GNSS and INS,the dynamic weighted fusion of GNSS/INS and the opportunity correction of GNSS/INS integrated system.The main conclusions and innovations are as follows:(1)The research status of GNSS/INS integrated navigation is analyzed.The existing research methods of INS error processing technology and GNSS/INS fusion positioning technology are reviewed.In view of the current problems of poor real-time navigation performance of GNSS/INS and low accuracy during frequent GNSS lock loss or long lock loss,the dynamic weighted GNSS/INS information fusion algorithm is proposed.(2)Based on the study of the existing INS error analysis methods,the INS error accumulation formula in time-domain is derived.Considering the different error characteristics of GNSS and INS in different stages of time domain,the INS cumulative error model in time-domain and the GNSS error model in time-domain are established.(3)Based on the error models of GNSS and INS in time-domain,the weight factors of GNSS and INS in information fusion are calculated,and the GNSS/INS combined positioning algorithm of dynamic weighted is designed.In addition,the moving carrier is constantly detected at rest in the process of GNSS/INS integrated system.When the moving target is in the static state,the integrated system can enter the opportunity correction state.(4)The simulation and performance of the proposed algorithm verify the effectiveness of the proposed algorithm.Compared with other combination methods,the GNSS/INS combined positioning algorithm of dynamic weighted can suppress the positioning error of the integrated system and improve the positioning accuracy of the integrated system.