Research On The Hybrid Positioning Strategy For Vehicle Using Dual-mode Gnss And Multi-sensors Based On Enhanced Digital Maps

In order to improve the positioning accuracy and reliability of the traditional GPS/INS integrated positioning system under the complex traffic environment,a dual-mode GNSS and vehicle sensors fusion positioning technology based on enhanced digital maps is studied in this paper.Meanwhile,the key issues such as road modeling,map making and multi-weight map matching algorithm are analyzed and explored in depth.Finally,the positioning results are optimized by using the enhanced digital map,which further improves the positioning accuracy and reliability of the system.The specific research content of this paper is as follows:(1)A design concept of an enhanced digital map oriented to the vehicle positioning system is studied.Based on this concept,the appropriate geographic information collection method and digital map editing software are selected.Then,the overall scheme of enhanced map making is given.(2)Based on the actual requirements of enhanced digital maps,a conventional road model and an intersection model are designed for different road network forms.And the Cardinal spline is chosen to fit the road plane curve.Then the optimization schemes of these two road models are proposed accordingly.(3)The problems of unified spatial-temporal reference and pseudo-range error correction in the dualmode GNSS fusion positioning process are studied.Then based on RISS,a vehicle positioning model is established.And a low-cost dual-mode GNSS and vehicle sensors fusion positioning system is used to obtain initial positioning result of the vehicle.(4)The vehicle positioning algorithm based on enhanced digital maps is studied,and a multi-weight map matching algorithm considering topological relationship,historical locus points,and other factors is proposed,which can further improve the positioning accuracy and reliability of the system.(5)Preliminary real vehicle experiments are designed and developed.Firstly,the road modeling method based on Cardinal spline in this study is compared with the method based on B-spline.Then the dual-mode GNSS pseudo-range dual-frequency correction,multi-sensors fusion positioning and multi-weight map matching positioning results are compared.The experimental results show that the road modeling method based on the Cardinal spline can realize a near-optimal balance between the efficiency and reliability requirements.And it can further improve the positioning accuracy and reliability of the system by using the enhanced digital map.