Principles And Practices Of WSCORS Construction

GPS surveying technique has been developed from static, fast static to real time kinematic and network RTK positioning,the positioning accuracy have been improved significantly at the same time. Network RTK, which the typical technique of is Virtual Reference Station(VRS), revals out the limitations of tradional RTK technique, greatly improves the efficiency and ensures the measurement accuracy and reliability at the same time. Continuously Operating Reference System(CORS) with multi-base stations providing a good platform for network RTK changes the acquiring way of spatial information and enlargs the area of GPS application. CORS is a kind of positioning system retegrates the internet, weireless communication technique, compute network, database and GPS and represents a navol developing trend of the traditional spatial positioning technique.This paper firstly introduces the current situation of CORS system development at home and abroad. The details of some famous CORS system are discussed and the feasibility and necessity of CORS construction are proposed. The following summarizes the basic concept of GPS and the positioning principles including absolute positioning, relative positioning, differential GPS positioning and all kinds of errors of GPS positioning.Secondly, WSCORS uses NRS software and the CORS equipment of south surveying and mapping science and technology co., LTD which based on virtual station (VRS) technique. When WSCORS was completed,the system’s function and performance index was tested and met the the design requirements. High precision dynamic coordinate frame is established, the system is provided with a good system completeness detection ability and can possess the conversions of coordinate and elevation systems.Finally using the observation data of reference starions in the65day to71day, the precise geocentric geodetic coordinates of WSCORS reference stations is obtained with software GAMIT/GLOBK software. In GAMIT baseline calculating processing, BJFS, KUNM, URUM, WUHN, SHAO, LHAZ of IGS reference stations and station XIAG from China Crustal Monitoring Network are leaded to participate in WSCORS baseline solution and the above datum stations coordinates are supported the net adjustment. So can provide the geographical spatial coordinate determinations of WSCORS reference satations, which are ITRF97,2000coordinates results. The data communication link between WSCORS and HHCORS and the datum uniform are discussed too. Through the data of shareing reference stations transmits to the control centers respectively, the connection of WSCORS and HHCORS is realized. The methods of uniform datum are introduced using nine parameter coordinate transformation model or making the basis standardization in baseline calculation or coordinate adjustment. By the general formula of coordinate transformation, the conversion can be getten after network adjustment.