Analysis on the Application of GPS-RTK Technology using in Yangkou man-made Island in Nantong City

The marine surveying is one of the branches of geomatics, and the sea navigational affairs project construction belongs to the marine surveying application category. The advent of GPS technology creates a new hightech avenue for marine surveying. This paper mainly discussed the application of GPS-RTK technologies in marine surveying. Taking the project of Yangkou manmade island in Nantong city as an example, it was introduced that the main job and work procedure of GPS technologies in under-water survey and steel sheet pile implementing the localization. Problems need to be cared during the procedure and how to solve them also were being discussed. And also some beneficial experiences of GPS technology applying in marine surveying were summarized. Keywords— GPS, steel sheet pile, independent coordinate system, under-water survey, section image Marine survey is a branch of geomatics. The main job is to get the basic information of the sea by surveying the sea and the seaboard in order to offer service for shipnavigation, national defense construction, seadevelopment and sea-research [1]. Marine survey mainly includes sea-navigation, marine geodesy and under-water topographic survey. Marine geodesy includes arrangement of geodetic control network and marine gravimetry. On the base of marine geodesy we can do under-water topography surveying, under-water topography mapping and the determination of the Marine geoid [2]. In addition, the work of marine surveying also includes maritime delimitation, hydrographic and oceanographic exploration and mining (marine fisheries, offshore oil industry, the continental shelf and exclusive economic zones of development), Haitian pipe laying, offshore engineering (such as the Harbour Engineering), fishing, dredging and so on. For the purposes of scientific research services(determining Earth shape and external gravity), marine surveying not only includes marine gravimetry, the average sea surface measurement and ocean surface topography, but also includes currents, sea level change, plate movement and tsunamis measurement[3,4]. Since the appearance of the GPS-RTK technology, the measurement mode realized the leap from point and line surveying to surface surveying. Water-depth measurement developed from survey point by point to Lines continuous measurement, with the advent of Multibeam Sounding Depth Measurement System, water-depth measurement developed to surface continuous measurement, raising the work efficiency and the density of water-depth measurement greatly [5]. At the same time data acquisition realized by simulation type to digital type leap. Information acquisitions tends to be more real-time and more standardization, information collection flat tends to be more multiplex, the management and using information tends to be more normalized, digit information product tends to be more diversified. GPS technology application develops fast then ever; Coastal GPS Differential Technique, WADGPS, Precise Point Positioning, Interstellar Differential Technique, RTK and Continuously Monitoring GPS Sites Technique are widely used in control surveying and sea navigation [6, 7]. This paper researched GPS-RTK technology in marine surveying on the base of project example. I. SURVEY OF THE PROJECT Yangkou Port artificial island project in Nantong Port is located in the west sun sandbar of Rudong beach shoal, Nantong City, Jiangsu Province, which lies to 32 kilometers west from Xiaoyangkou Port, 50 kilometers southeast from Lvsi Port, and the geographic location of which lies to 32°32′50′′ north latitude, 121°25′35′′east longitude, and 13 kilometers away from the nearest land coastline. Artificial island project is the most important Corresponding author: Yufeng Zhu, Master, Lecturer. Email: yfzhu@ecitcn; phone 86 794 8258309; fax 86 794 8258309. Fund Project: Natural Science Foundation of China (40874010). 1444 JOURNAL OF NETWORKS, VOL. 6, NO. 10, OCTOBER 2011 © 2011 ACADEMY PUBLISHER doi:10.4304/jnw.6.10.1444-1451 component of Nantong Port Yangkou Port system projects which includes Area Waterways, Pierhead Trestle, Artificial Island, and Continental Island Channel. Artificial island is located in the beach of the west sun sandbar with the elevation of -2.5 ~ +4.0 meters, the coastal sedimentary environments is greatly influenced by tides, sandy soil and cohesive soil alternated with the depositions metrically, of which the northeast wind has the most influence on the project . Design water level is +6.89 meters, low water level is +0.81 meters, the extreme high water level is +9.00 meters, and the extreme low water level is -0.25 meters. In order to prevent the seabed washout, the wash-prime steel pile was hitted into the 50m~65m place to the axis of the artificial island northeast side. The numbers of YASP-IV type of antiscour is and is 277, and the number of OZ-20 type is1885, the AU-20 type 200, and the AU16 type 599, so the total number is 4860, 84366 meters’ long. This project scope includes: island wall structure, the formation of fore backfill ground , II and III, inside partition embankment, LNG tanker spills construction. And the area of ground (ING receiving station) is 299,660m, the area of oil and chemical industry in ground II is 326,600m, the area of mineral and coal in ground III is 806,700m , the area of fore backfill ground II and III is 226,340 m , the total length of the island wall structure is 4688.458m, the total length of inside partition embankment is 3477.094m, the plan sketch is shown in Fig.1. Figure 1. Plan sketch of the project The GPS primary control network of Yangkou harbor in Nantong harbor district was trusted to Nantong survey bureau by the entrepreneur; it was arranged in October 2006. The original control network contained 13 control points, which were 3 A-grade points, 6 B-grade points, and 4 C-grade points. Elevation control network was surveyed by the method of second-class leveling surveying. According to the project's characteristic and the survey's special details of the construction scene, 5 control points were selected (Changsha Junior middle school, B03, B04, B05 , C01) as the primary control points of the under-water topographic survey. The data of control points were showed in the next Table1. TABLE I. DATA OF CONTROL POINTS UNIT: METER Number Name Ordinate X Abscissa Y Altitude