Papers by Keyword: GPS Data

Abstract: Taxis account for a large percent of urban public passenger transport. This research proposes a monitor model of analyzing unoccupied taxis at a defined area. By scientific analysis of taxi GPS data precision and quality, 16,255 valid taxis in register list were filtered, and two coefficients were introduced to correct the taxi monitoring model. Based on the location reports of valid taxis, the number of unoccupied taxi which was able to dispatch to meet passengers’ demands can be predicted. Take the terminal 3 of Beijing Capital International Airport as a case study, the field investigation results show that the precision of model reached 87.25%. It provides reliable systematic support and alert for a low taxi number when there comes up large taxi travel demand during the peak period or under severe weathers.

Abstract: Effective management and evaluation of on-site supervision staffs in large hydropower project is a key method to strengthen management, improve efficiency, and ensure the progress and quality of projects. A new method based on smart phones and real-time tracking technology was developed to manage and evaluate on-site supervision staffs. The location information of supervisors at the construction site is collected and uploaded to the server by smart phones containing a GPS data uploading application. The server stores and processes the data, and displays the location and the track of staffs on the web page to achieve real-time monitoring. The collected GPS data is deeply analyzed to identify the specific work context of supervisors and to build 3 indicators: Field Work Time, Effective Work Time and Effective Work Scope which are effective indicators to measure the workload. The feasibility of the method was verified by simulation experiments. Experimental results show that the proposed method can determine the real-time position of supervisors accurately, and identify their work contexts effectively. Extracted indicators meet the realities of situation. The method possesses abroad potential in large hydropower construction management.

Abstract: Due to development in computer and information technology, data access and collection have becoming more and more convenient. In many cities’ transit system, transit vehicle GPS data and passenger IC card data could be provided. This paper focuses on the method that uses the passenger IC card data (only record once per trip) and transit vehicle GPS data to generate the transit OD matrix. After analyzing the characteristic of transit trips, the author gives the definition of continuity for a transit trip. Based on this definition, this paper then presents a search method to generate the transit OD matrix. The validity of this method has been tested in the modeling process for Zhengzhou city’s comprehensive transportation system. At the end, it is hoped that this research may give a useful lesson for other cities’ transportation modeling practice.

Abstract: Short-term adverse weather conditions have a direct impact on geological disasters. However, the data source of high-precision weather on real time can be provided by GPS technology. At the same time, the high-precision and real-time weather forecast can provide important and basic information for geological disasters monitoring, forecasting and prevention. However, the precision of the total zenith delay in troposphere directly affects the estimating precision of the water vapor contents over stations, which affects the accuracy of real-time weather forecast. In this paper, the total zenith delay of GPS observational station is solved respectively by GPS data on GPS observational station grouped with different IGS stations using high-precision software-GAMIT/GLOBK developed by the Massachusetts Institute of Technology. The solving results are comparatively analyzed to draw：the best number of IGS tracking stations by grouping network for improving the precision of the total zenith delay in troposphere is 3. It is of great realizable significance.