Design And Implementation Of Dam Construction Monitoring System On PDAs

In dam information system, it is really needed to find a mobile information platform applicable to field operations, offering functions like data-cllection, multi-level verification and location based service. Development of technologies, especially the wireless communication, network deployment and mobile location technologies, provide convenience for realization of efficient dam construction monitoring system on embedded device.According to the specific requirements, this thesis designs and implementes a construction monitoring system based on PDAs. The system is developed on Windows Mobile, which can decrease development complexity and maintenance expense. It uses GPRS for wireless communication between clients and servers to ensure network connection and coverage, and uses GPS to realize location functions in dam area to improve positioning precision and flexibility. In this thesis, the detailed implementation of dam construction monitoring platform is discribed, we use three-layer C/S structure, and the main contents can be subdivided into data collection, remote transmission, multi-level verification and location service. For the function flexility, client customization is used in data collection and multi-level verification. The mobile location solution is based on DRG (Digital Raster Graphic) and GPS, and we bring some new treatments for spatial data to conquer the poor computing power and slow screen speed of PDA. At the end of this thesis, a hybrid location method is researched to avoid the conditions of no GPS signal, which combines GPS with WLAN location methods. And the feasibility of this method is verified.In order to ensure the reliability and stability of the system, many tests for functions and performance are carried out. The contents of these tests contain data-collection, GPRS data transmition, server concurrent pressure, response to map operation and location performance. The results show that all the system functions meet the demands and the position map-matching also has a good effect.