Applied Research Of Single Base CORS Technology In Land Surveying And Demarcating

In recent years, with the rapid development of the society and economy, the positioning technology based on the conventional GPS-RTK exceedingly makes convenience for the users who need data acquisition of dynamic measurement with high precision. Nevertheless, the traditional RTK(Real-Time Kinematic) positioning technology is criticized cumulatively by mapping department due to its insufficiencies in measurement range, data communication chain, move of reference station(base station) for ambiguity resolution, operating efficiency along with the increasing distance between moving station and reference station(base station). In order to meet the requirements of mapping departments on high-accuracy and high-efficiency mapping production, the problems on how to break off the inefficiency and complexity of traditional GPS- RTK mapping production and how to achieve a broader scope of work are becoming more and more prominent, especially for the positioning of high precision dynamic in strip projects such as water supply engineering, railway engineering, road engineering. In pace with the speedy development and modification of information technology, computer network and communication technology, engineering, e-government, e-commerce, digital city of reality, digital province of reality and digital earth of reality get close contact, which makes it possible to realize real-time transmission and processing of massive data, so to find a kind of efficient, low-cost, high accuracy real-time dynamic positioning system is particularly significant. In this case, the CORS system(Continuously Operating Reference Stations) has entered the vision of manufacturers and Mapping Department, and it gains rapid development in all industries owing to its adaptive comprehensiveness. At present in our country, a large number of provinces, cities,towns and industries also set some such reference station network systems, such as Jilin CORS, Chongqing CORS, Guangdong CORS, Yichang CORS, to satisfy industry demands. This paper takes “the water supply project from Songhua river in the central city of Jilin Province "as the basic of research, systematically introduces the application of single base CORS system in plane surveying, height measurement,topographic map measurement, boundary points lofting of land surveying and demarcating projects through the concrete practices.The applications of single base CORS technology in land surveying and demarcating, not only reduces the production cost in the provision of efficiency of mapping production, but also offers a reliable verification method for the application of advanced measurement technology in practice, to broaden the application scope of the method and supply valuable experience for enriching the measuring means,especially the application in strip project. However, CORS technology also has some limitations; it is still difficult to solve problems in some special areas by using GPS-RTK in measurement. For example, in the forest or some areas with underdeveloped network where still have blind angles. But with GPS-RTK satellite receiver, the plough system, the development of network construction, the blind angles will become less and less. In this paper, it analyzes the problems encountered in the application of CORS and puts forward some solutions. Research results have considerable theoretical significance, and provide the units and individuals that use single base CORS system with practical guiding significance of mapping.In summary, the research results are as follows:1. It participates in the establishment of single base CORS system, and tests the performance indicators and functional indicators of single base CORS system,including the test of accuracy of system static and dynamic positioning, system usability test; system functional test includes the test of remotely control ability, the test of system fault-tolerant ability, compatibility test. Through tests, the paper draws that the service range of a single reference station CORS is about 30km; with the increase of distance between moving station and base station, the precision of point position is decayed; initialization time of RTK usually is 3-40 seconds. The system possesses availability, reliability and efficiency, which can be fully applied in projects of land surveying and demarcating.2. It takes “the water supply project from Songhua river in the central city of Jilin Province "as an example, connects RTK with single base station in practice, applies opposite side measurement mode of total station instrument to verify the accuracy of RTK layout mapping control point. Practice has proved that application of total station instrument on side length of all RTK dynamic measurement, the maximum deviation of length is △ Lmax=2.4cm, average deviation is △ L=0.96 cm, mean square error of a point: ± 0.9cm, which can fully meet the requirements of therelevant norms based on RTK layout mapping control point of CORS system.3. This paper analyzes the problems encountered in the process of RTK measurement and puts forward effective solutions by practical application.