| The underwater sensor node location depends on the coordinate provided by the anchor node.Because the cost of the anchor node is much higher than that of the ordinary node,the number of anchor nodes deployed in the network is much smaller than that of the ordinary node.While the anchor nodes are randomly deployed in the network,and the node keep moving and dispersing due to water flow and aquatic organisms touch.These will lead the emergence of isolated nodes.The isolated node can't be located if it can't obtain enough number of neighbor anchor.In the view of this problem,this paper presents one kind multiple anchor node cooperative localization method MACL to achieve two-hop anchor node distance estimation.In the MACL localization method,the unknown node will request two-hop anchor node information from its neighbor node when the number of one-hop anchor nodes is insufficient.Its neighbor node will send its own one-hop anchor node information to the unknown node.The unknown node will select two neighbor nodes with a common one-hop anchor node.Then the unknown node will project the two neighbor nodes and their one-hop anchor nodes to the depth of the unknown node by using the projection technique.After protecting,the unknown node constructs the geometry including the unknown node,the two neighbor nodes and their one-hop anchor nodes and their projection nodes.Then the unknown node will compute the distance between itself and the two-hop anchor node by looking for the geometric shapes Edge – angle relationship.When the number of anchor nodes is satisfied,the unknown nodes will compute its position by using the trilateral measurement method through projection technique.This paper uses MATLAB simulation platform to simulate the proposed MACL location method and then compared with the existing location method.The experimental results show that the method proposed in this paper has higher node coverage and smaller localization error and lower communication cost. |
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