Research Of Marine Monitoring Sensor Networks On Key Technologies

Marine monitoring sensor networks are wireless sensor network extensions in the oceans. It is deployed in an extremely complex marine environment for specific applications to achieve real-time monitoring of the oceans. Marine monitoring sensor networks include two parts:one part is deployed underwater and the other part is deployed on the sea surface. In a broad sense, ocean monitoring sensor networks include land-based marine near-shore networks and space-based satellite networks, so as to form a three-dimensional monitoring of marine sensor networks. This article is mainly focus on a narrow sense of the ocean monitoring sensor networks, and includes the water surface sensor networks and underwater sensor networks.The water surface sensor networks which use radio for communication and networking can be used to detect wind direction, wave height, tides, water temperature, light, water pollution, and other ocean-related information. In addition to that, the water surface sensor networks are responsible for the information transmission of the underwater sensor networks. Underwater sensor networks are currently the main method of underwater acoustic communications and networking. Compared with the terrestrial wireless sensor networks, underwater sensor networks have the following characteristics:communication channels with high delay, delay dynamic, high-attenuation, high bit error rate, multi-path effects, doppler dispersion and highly dynamic changes of the channel, low-bandwidth which are considered as the most difficult wireless communication channel; networks with mobility features; battery-powered nodes and the battery replacement is more difficult; the node's engery consumption for the sending mode is often a hundred times than that of the receiving mode; due to the reason that nodes are expensive, underwater sensesor networks are always sparsely deployed. Thus, we should design new protocols to deal with these features of underwater sensor networks.In this paper, we mainly focus on the following key technologies of marine monitoring sensor networsks:1. For the sparse deployment of marine monitoring sensor networks, in particular mooring marine monitoring sensor networks, the energy balance problems are investigated. Marine monitoring sensor network typically use battery-powered nodes, and the battery is not easy to replace. However the balanced energy consumption will affect networks'lifetime. The mooring of marine monitoring sensor network has the characteristic of sparse, which makes the balanced energy consumption more important. In response to these characteristics and energy consumption according to an underwater model, this paper presents two algorithms EBH and the DIB to extend the network lifetime. EBH is a hybrid data transmission algorithm in which the nodes change working mode automatically according to nodes'residual energy to reach balanced node consumption among the entire networks. DIB is a heterogeneous network based algorithm, and it achieves energy balance by configuring the nodes with different initial energy level according to their working load.2. Localization for the marine monitoring sensor networks is a key technology of obtaining real-time marine monitoring information. Whether environmental monitoring, disaster avoidance, underwater security intrusion monitoring, energy-efficient routing control, are inseparable from the node location information. The node's engery consumption for sending data is often a hundred times than that of receiving data. With this feature, as well as the characteristics of the sparsely deployment of underwater networks, this paper presents two passive localization algorithms. These algorithms use AUV to assist localization which transfers the localization energy consumption from node to the AUV, because AUV is easier to replace or recharge energy. In the passive localization algorithm, the node can calculate its position after receiving location beacons sent by the AUV. The algorithms are applied to two-dimensional and three-dimensional underwater environment. Both algorithms take advantage of the angle of directional hydrophone to send beacons, which simplify the positioning algorithm and reduce energy consumption. In addition, the algorithms do not depend on the networks'node density, and therefore they are more suitable for marine monitoring sensor networks. 3. Marine monitoring sensor network security intrusion detection is an important component of defense and safety. It is used for the port protection, maritime border protection, marine facilities, such as offshore oil platforms, fishing facilities protection and so forth. In this paper, we have done research on vessel intrusion detection on the sea surface, and propose an algorithm. We mount imote2 with three-axis acceleration sensors on buoys, and then deploy the buoys on the sea for a preliminary experiment. Through data analysis and processing, we found that ship waves and the ocean waves have different spectrum properties. With these features we have designed a three levels intrusion detection algorithm. According to the characteristics of ship waves, we combine temporary cluster and fixed cluster approach to have a better use of space-time relevance of intrusion detection. In addition, with the manual deployment, we can estimate the speed of the vessel.Marine monitoring sensor networks can be used for marine environmental protection, resource conservation and management, disaster monitoring, marine engineering, offshore production operations, military and other activities by providing better information platform. China is a major ocean country and ocean monitoring sensor networks has a broad application prospects. As researches on marine monitoring sensor network technology continue, it must have a good support to the sustainable economic development.