GPS-RTK技术在杭州湾跨海大桥桥址地震勘测中的应用

杭州湾跨海大桥桥址区域发现大面积天然气，为合理开发油气以及保证杭州湾跨海大桥施工建设和运行安全，为此采用地震方法探明该地区地层结构及油气分布状况。杭州湾跨海大桥桥址水域宽约30km，因杭州湾潮汐影响，水流湍急，水面高程变化很大，平潮与退潮后水位差10余米，作业条件十分困难，用常规定位测量方法是不可想象的。在实时导航定位中采用现代GPS-RTK（Global Positioning System Real-Time Kinematic）技术，实现了水上远距离、大范围的地震测量实时精确定位，并采用事后差分技术提供震源三维坐标数据，为地震空间定位分析提供了可靠保障。

THE APPLICATION OF THE TECHNICAL GPS-RTK IN THE EARTHQUAKE SURVEY AT THE BAY OF HANGZHOU BIG BRIDGE

A large area of oil field is found at the bay of Hangzhou big bridge,and to exploit reasonably the oil under the sea and to ensure the construction and its safety of the bridge ,it is necessary to explore the stratum's structure and its state of oil. The water area's width of Hangzhou big bridge is about 30 kilometres, and because of the effect of tide,the sea water flows rapidly and its elevation changes greatly, the difference between slack tide and ebb tide is about 10 metres. The work condition is hard ,so it is unimaginable to use our common way to do navigation and survey. The author adopted the technical GPS RTK(Global Positioning System Real Time Kinematic), which is called the advanced technique of three dimensional space position system. and has navigated the ship in the oil field at a long distance and in a large scale field. By using the technique of post difference we can give three dimensional space coordinate, so this ensures that we can carry out spatial seismic analysis reliably.