Construction of tsunami disaster reduction system using the GPS tsunami measuring system

我们设计了一种海啸监测系统，它使用携带RTK-GPS的浮标。浮标处采集的信号被传输到陆上基站，并在基地进行RTK处理。分析的浮标运动被传输到大船渡市政厅和消防局，以监测海面运动。该系统是在1999年在相模湾进行的初步实验的基础上改进的。本系统的长期试验于2000年1月23日在大船渡市近海开始。距岸边约1.5公里，设计了为期一年的试验。该系统能够记录到6月25日(日本夏令时)传播到太平洋上的海啸，海啸是大约一天前在秘鲁近海发生的地震造成的。测量海啸的精度似乎在1-2厘米左右，足以探测到海岸上的危险海啸。分析后的数据被自动上传到网页(http://tsunami.ekankyo21.com/))，任何人都可以在任何可以使用互联网的任何时间监测海面。尽管到目前为止，试验取得了成功，但要将该系统扩展到更多的近海设施，现在显然存在一些问题：1)将RTK定位的精度保持在超过10公里的基线上约2-3厘米，2)在更深的海洋上可靠地系住浮标，3)强大的数据遥测系统和4)开发自动海啸探测算法。

We have devised a tsunami monitoring system which uses a buoy that carries a RTK-GPS. The signal acquired at the buoy is transmitted to the onshore base station and the RTK processing is done at the base. The analyzed motion of the buoy is transmitted to the Ofunato City Hall and the Fire Station to monitor the sea surface motion. The system was an improved set based on the preliminary experiment conducted in the Sagami Bay in 1999. The long-term experiment by the present system began on January 23rd, 2000, at the offshore of Ofunato city. The distance from the shore is about 1.5km and one year of experiment was designed. The system was able to register the tsunami on June 25th (JST) that was propagated over the Pacific, which was generated by an earthquake offshore Peru about one day before. The accuracy of measuring the tsunami seemed to be about 1-2cm, which is good enough to detect hazardous tsunami at the shore. The analyzed data are automatically uploaded to the web page (http://tsunami.ekankyo21.com/) which allowed anyone to monitor sea surface at any time where internet is available. Although the experiment has been successful so far, some problems are now evident to extend the system for further offshore establishments ; 1) maintain the accuracy of RTK positioning to about 2-3cm for more than 10km baseline, 2) reliable tethering of the buoy at deeper ocean and 3) robust data telemetry system and 4) development of an automatic tsunami detection algorithm.