| In-vehicle navigation systems generally have requirements for positioning all day,all sections,and high accuracy.With the development of sensor technology and the improvement of computer computing power,the practical application of multi-source heterogeneous sensor fusion will be a natural development trend.The research on the embedded module system of vehicle multi-source integrated navigation will be conducive to the promotion and application of high-performance vehicle navigation system.The main research content and innovations of this thesis can be elaborated as follows:Aiming at the problems of low reliability of single-sensor positioning and limited resources of embedded systems,the GNSS/INS/ODO/BARO combined navigation algorithm is adopted,and an adaptive factor robustness algorithm based on GNSS status is proposed.The robustness algorithm dynamically adjusts the observation uncertainty covariance matrix by using GNSS status information such as differential positioning flags,position precision factors,and the number of visible satellites,combined with adaptive factor theory,thereby effectively suppressing the influence of GNSS gross errors on the Kalman filter state quantity Impact.Experimental results show that,compared with the GNSS/INS integrated navigation method,the use of odometer improves the system’s horizontal positioning accuracy by 27.62%(2σ),the use of barometer increases the system’s elevation positioning accuracy by 12.57%(2σ),and the use of robust algorithms The positioning accuracy of the system is improved by 21.65%(2σ).Aiming at the potential fault problem in the fusion of multi-source heterogeneous sensors,the two-state propagation χ^2 fault detection algorithm is improved,and a model based on two-level fault inspection is implemented.The experimental results show that,when the RTK fixed solution and the noise-added positioning solution are considered comprehensively,compared with the traditional method,the improved two-state propagation χ^2 fault detection algorithm has better fault detection and isolation capabilities,and the two The first-level fault inspection model can effectively detect GNSS soft faults,GNSS hard faults,ODO faults and INS faults.Aiming at the real-time and scalability requirements of embedded systems,an embedded software and hardware design scheme for multi-source fusion navigation is adopted.Realizes module-level RTK data acquisition.The device can independently obtain the differential correction number through the mobile communication network and calculate the RTK positioning solution in real time;according to the performance characteristics of each sensor and the hardware interface characteristics,it realizes the multi-source heterogeneous oriented car navigation The sensor’s time synchronization strategy;the use of DMA and other software and hardware combination methods,so that the driver occupies less than 1% of the CPU computing resources.Under the complex actual drive test environment,the horizontal positioning error is less than 1m(2σ)and the elevation positioning error is less than 1.5m(2σ)navigation positioning accuracy,which proves the superiority of the vehicle-mounted multi-source integrated navigation embedded module system. |
