Research On Ultra-tightly Clupled Navigation System Based On MINS/GPS

At present,industry applications such as autonomous driving put forward higher requirements for the positioning stability and positioning accuracy retention capabilities of vehicle navigation systems in complex urban environments.In the existing mature MEMS inertial sensor-based inertial navigation/satellite(MINS/GPS)integrated navigation system,when the satellite signal is partially obscured or interrupted for a short time,the positioning accuracy is completely dependent on the performance of the MEMS inertial sensor,and there are problems such as unstable positioning and poor accuracy retention.On the one hand,the ultra-tightly coupled navigation system based on MINS/GPS takes advantage of the short-term accuracy of MINS to aid the GPS carrier tracking loop and improves the anti-jamming capability of satellite positioning.On the other hand,it uses multi-sensor data fusion technology to improve the short-term loss of satellite signals.The ability to maintain positioning accuracy can improve the comprehensive positioning performance of the vehicle integrated navigation system in a complex urban environment.In this paper,aiming at the problem of positioning performance degradation of MINS/GPS integrated navigation system caused by satellite signal occlusion,interference or short-term loss in urban environment,ultra-tightly coupled navigation system based on MINS/GPS is adopted,and GPS carrier tracking loop method aided by MINS and multi-source information fusion method are studied.The correlation is verified by mathematical simulation,hardware in the loop simulation and sports car experiment The effectiveness of the method is verified.(1)The main research content of the thesis includes the following four aspects: Based on the principles of inertial navigation and GPS navigation,the MINS/GPS ultra-tightly coupled navigation system is designed,focusing on the inertial navigation update method,GPS baseband signal processing and positioning method,integrated navigation positioning method based on Kalman filter,etc.(2)Taking the basic second-order PLL as the object,the GPS carrier tracking technology is studied,and the reason why the GPS carrier tracking loop based on the second-order PLL cannot achieve both dynamic performance and anti-jamming performance is analyzed;the MINS-aided GPS carrier tracking loop is studied.It also compares and analyzes the auxiliary effects of MINS with different accuracy and different update rates,and puts forward suggestions for the device selection and scheme design of the MINS module in the ultra-tightly coupled navigation system.(3)The MINS/GPS/odometer multi-source data fusion method is studied,and the MINS/GPS tight integrated navigation scheme aided by the odometer is designed.When GPS is valid,the MINS/GPS combination method based on pseudorange and pseudorange rate is used to ensure the stability of positioning;when GPS is lost for a short time,the MINS/odometer speed combination method is used to improve the positioning accuracy of the combined system.The simulation results show that the multi-source data fusion method based on MINS/GPS/odometer can effectively improve the integrated positioning ability of the integrated navigation system in a complex urban environment.(4)By introducing MINS auxiliary information on the existing satellite navigation experimental verification platform,it is verified that the MINS-aided GPS carrier tracking loop method can effectively improve the satellite receiver's ability to track satellite signals with low carrier-to-noise ratio;using synchronously collected micro-inertial sensors Data and the original satellite navigation data(navigation message and pseudorange,pseudorange rate information),the MINS/GPS tight combination method was simulated in half-physical form,and the positioning performance under the condition of satellite signal interference was verified;MINS/GPS/ The odometer integrated navigation system verifies the multi-source data fusion method,and it is verified through the sports car experiment that the multi-source data fusion method can effectively improve the system's positioning accuracy retention ability when the GPS satellite signal is blocked.