Marine ubiquitous sensor network at harbor/shore area

本研究旨在基于高精度的位置信息，实现包括水下传感器节点和港口附近浅水区海底传感器节点在内的海洋传感器网络。由于第一年对已开发和评估了许多系统的陆地上的类似研究进行了调查，研究对象从泛在环境转移到研究成果较少的海洋领域。主要结果如下：特别是在海洋中可以实现高精度GPS的传感器网络研究中，更是受到了重视。无处不在的、更大范围的无线网络海洋传感器网络节点密度稀疏，海上传感器网络节点之间的距离比陆地长。对长距离PAN进行了评估，采用GPS同步方式和高效晶体滤光器窄带扩频方式实现了原来300m左右的极低功率通信。低端L1、CAGPS/天线的高精度测量利用L1/CAGPS模块u-blox 4T在海面附近用原始软件评估了RTK GPS的可能性。单历元动态GPS方法1秒内固定成功率为30%~40%。浅海超声波通信实用化研究该浮标是为构成利用水中超声波的传感器网络节点而设计的，并在约2m水深范围内进行了收发试验。为了消除相位的影响，采用了FSK方法。针对海面和海底变化快、多路径波的特点，采用了通信决策反馈均衡器(DFE)方法。针对海底传感器的位置估计问题，开展了基于MEMS的自主导航研究。并对MEMS传感器进行了初步评价。这些研究将继续进行。

This research is to realize the oceanic sensor network including the sensor node in underwater and bottom of the sea at shallow water area near harbor based on highly accurate location information. As a result of the investigation at first year about similar research on land where many systems has been developed and evaluated, the research object was shifted from a ubiquitous environment to the sea field where the research results were little.The main result is as follows. Especially, it is given priority in the sensor network research that uses highly accurate GPS that can be achieved in the ocean.1. Ubiquitous, wireless network in larger areaThe density of marine sensor network nodes was sparse, and the distance between nodes for marine sensor network at sea is longer than on land. The long distance PAN was evaluated, and the original very low power communication of about 300m was enabled by GPS synchronous method and efficient Crystal filter narrowband SS method.2. Highly accurate measurement with low end L1,CAGPS/antennaThe possibility of RTK GPS by using L1/CA GPS module u-blox 4T was evaluated by original software in the vicinity of the surface of the sea. The fix success rate of 30-40% was obtained for one second by a single epoch Kinematic GPS method.3. Practical use research on supersonic wave communication in shallow water areaThe buoy was designed, which was produced to compose the sensor network node where the supersonic wave in water had been used, and it experimented on the sending and receiving wave in region of about 2m in depth. To exclude the influence of phasing, the FSK method is adopted. Because of rapid change and many multipath wave from sea surface and from the bottom, the communication DFE (Decision Feedback Equalizer) method was used.4. The position estimation of sea bottom sensors.Research of autonomous navigation by MEMS was started. and MEMS sensor was evaluated as first step. These study will be continued.