Marine ubiquitous sensor network at harbor/shore area

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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.