Map-matching Method Designing Based On Road Spatial Relations

The vehicle carried GPS, which have attracted more and more attention, will gain great economic and social benefits, along with GIS (Geographic Information System), GPS (Global Positioning System) and GPRS (General Packet Radio Service) technologies becoming more advanced. As there are always some positioning errors from any positioning technology, car navigation systems will not be able to play its due role, or even lose their own value of existence if the errors are too much. In order to improve navigation accuracy, people often work on the hardware, however the cost will increase. A possible approach with affordable costs and improved accuracy is to use software aided map matching, which will improve navigation accuracy.Map matching algorithm is a correction method which eliminates positioning error between measurement points and real points using corresponding algorithms. The core of the method is the introduction of the corresponding algorithms. The measured location of the vehicle at a certain time is generally not the real position because of the inherent errors in GPS system. The map-matching algorithms will eliminate error between the two and correct the measured location on the road.In the paper, the map matching algorithms and their roles in positioning and navigation system were discussed in detail, the factors which affect navigation accuracy were analyzed, and several common matching algorithms were studied. As a result, different methods, different implementations, and different elements considered, each method can solve a certain range of problems. Nevertheless each method has drawbacks. On the basis of previous studies, this paper made full use of the available information and designed matching methods which will take matching criteria based on three elements of road space. When distance elements were studied, the idea of calculating distance between straight lines based on the method of area in cartography was used, and the thinking of definite integral in advanced mathematical which seeks areas of polygons and arc lengths of curved was used rationally, curve expression was obtained by curve fitting. In order to make matching algorithm more comprehensive and applicability, algorithm fusion of distance, angle and topology relation were made and the fusion function expression is given. To verify the rationality and reliability of the algorithm, Car experiment was made, rationality and reliability of map matching algorithm based on spatial relations of the road was described qualitatively and quantitatively and the desired effect of the design was achieved.