Research On High Precision GPS Positioning Method For The Track Traffic Station

Maintenance inspection is an important work which related to the safe operation of the track traffic. The equipments are numerous and scattered on the track traffic station, which need a lot of repairmen to check and maintain timely, it is particularly important for the real-time location, tracking and management to the people. The problem of the GPS positioning has been researched by domestic and foreign scholars, but the proposed GPS positioning method is generally applied to vehicle in the highway traffic system, which rarely involves personnel location on the traffic station. Although some kinds of improved GPS matching algorithm have been proposed, they don’t have the characteristics of the track traffic station into consideration, which generally exists great problems of positioning error, data drift and unable to realize high precise positioning to the personnel. So, based on the analysis of the characteristics and topology structure of the track traffic station, a high precision GPS positioning is researched from three parts of GPS data acquisition, data pretreatment and GPS positioning matching in the paper. The main works are as follows:1. The connection-control point method is used to collect GPS data in the paper, which can reduce the error caused by data drift. Based on the topological structure characteristics of the station, the method proposed to set some connection points and control points in the key position with which accurate coordinate are known, and adjusts the collecting GPS data by the constraint of these points.2. In order to improve the efficiency and instantaneity of the data pretreatment, a real time self-adaption dynamic correction method which based on the data change rate is researched in the paper, it determines the upper and lower correction limits by the change rate of rolling sample data, then find the error points according to this correction range, and eliminate or interpolate them.3. A map matching algorithm based on two-circle method is researched to ensure the GPS positioning precision in the paper. It divides the track station into small rectangular areas, then obtain the track segment to be matched though combination of the concentric circle and the rectangular. Then different optimize matching algorithm are used to different characteristics track area in the paper:i. The position point matching algorithm is used for the ordinary straight and curved track;ii. The map-matching algorithm which based on the constraint of historical conditions is used for the adjacent parallel track, it makes full use of history matching information to constraint the current GPS point, and can improve the jump matching between the adjacent track;iii. A separation line which is build by T-S fuzzy model is used for the track switch buffer, it determines the current track for the matching point through classify, and can reduce the matching errors around the switch;Finally, the experimental results by Wuhan subway show that the high precision GPS positioning method proposed in the paper effectively improves the personnel positioning on the track traffic, the positioning precision is up to2meters and the matching rate reduced to3%. The method has the advantages of speedily matching, highly efficiency and low rate of mismatch, and it realize high GPS positioning for the repairmen on the track station under the condition of real time matching.