Height Data Acquisition And Map Matching In Three-Dimensional Navigation System

With the development of road construction and requirement of transport system, overpass has been more and more widely used. Space-separated methods are used to eliminate cross-traffic conflicts in path plane. At the same time, achievement of automatic driving with the use of electronic map database of road information and traffic information has become an important development direction of intelligent transportation system. Therefore, effectively dealing with map matching on overpass becomes very important to the navigation system.However, there are two shortcomings in current two-dimensional vehicle navigation systems in dealing with overpass sections. On one hand, drift phenomenon often occurs when the vehicle is running on the ramp or the main road of the overpass which is parallel to each other due to the accuracy of GPS signals and electronic map. On the other hand, GPS signals are often subject to temporary suspension near the overpass, and then if the vehicle runs from ramp into the main road or from the main road into the ramp, interpolation error will appear in inertial navigation systems. Map matching errors due to the two deficiencies above lasts a long time before they are corrected. Therefore, the map matching performance on overpass of the navigation system needs to be improved on accuracy and real-time aspects.In this paper, the topic is study of height data acquisition and its application in map-matching in three-dimensional navigation system, including the acquisition of height data, the ways how to use the height data, as well as how to improve the performance of map matching in overpasses using height data.First of all, an altimetry is designed to obtain the height data which is accurate enough to the application module. In this section, the main task includes: the selection of using SCP1000-D11 pressure sensor chip and writing code for its driver, the description of the principle of height measurement from pressure and the conversion formula, the design of error correction algorithms based on the analysis of error sources of height data, the authentication of height data amendment effect through a static test experiment, and the summary of the entire process of height measurement module ultimately.Second, the application of height data in map matching in overpasses sections in three-dimensional navigation system is focused on. In this section, the main task includes: the analysis of defects in map matching on overpass sections in two-dimensional navigation system, the analysis of ways and principles to use height data, the analysis of the way how to conduct map matching in overpass sections based on height data in detail, the portrait of map matching algorithm on overpass sections based on height information used in this article, the data collection through actual car driving, the simulation of D-S evidential reasoning map matching algorithm which is now widely used in two-dimensional navigation system and the algorithm proposed in this article in the MATLAB, the authentication of improvement of performance of three-dimensional navigation system on accuracy and real-time aspects on map matching on overpass sections through comparing the experimental results of two algorithms.The algorithm of map matching on overpass sections proposed in this paper which is based on height information is very important to the improvement of the entire navigation system performance, and this has reached the desired objective of this article.There are 33 figures, 10 tables and 42 references in this article.