Research Of Wireless Sensor Network Node Localization Algorithm Without Ranging

As wireless technology has a sensing sensor, collection, and wireless communicationcapabilities, coupled with a large number of sensor nodes, distributed random, Therefore wirelesssensor has tremendous applications in military, industrial control, civil, medical assistance,environmental monitoring, underground coal mines, forest fires, urban transport and so on.The wireless sensor nodes localization is prerequisite for the monitoring information targetpositing. Currently there have been a variety of different algorithms. In accordance with the nodesneed ranging into ranging and free ranging. Location algorithms based on high complexity, highenergy consumption, may be affected by environment, do not meet mobile location between nodesaccording to the network connectivity requirement. The paper focuses on the range free nodelocalization of network, node localization without ranging applications for APIT algorithmimprovements and DV-Hop algorithm in underground coal mines. The main innovations of thisdissertation are the following three points:(1)Within a point of the triangle approximation currently testing non-ranging techniques(APIT), This paper proposes an improved algorithm based on the area of localization algorithm(S-APIT) under a two-dimensional space. Location area between the node and use the algorithm todetermine a node is on the inside or outside of the triangle, to solve the classic algorithms rely onsensor network communication overhead and node density. Improved algorithms can be applied ina resource constrained environment.The simulation experiment proves that in the less dense anduneven distribution of communication radius changing circumstances, compared to the classicalmethod, the improved algorithm to improve the positioning accuracy, reduce errors and improvethe localization rate of unknown nodes.(2) DV-Hop algorithm in the underground coal mine roadway nodes communicate in adifferent roadway, according to the characteristic, create a different coordinate systemclassification, using the coordinates of anchor nodes or the length of roadway, the minimumnumber of hops between the calculated distance tunnel anchor nodes and nodes and nodes,between the unknown node and anchor node distance, then suing the maximum likelihoodestimation method, the coordinate the unknown node, so as to obtain the average error rate,together with the coverage and, through simulation the influence lever l drift layers change on theerror rate. (3) An average of two per hop for improvement, the first is the use of an unknown node toanchor nodes and unknown nodes average hop distance to the nearest anchor node means averagehop distance. The second is the average of the unknown node to jump between all anchor nodes.From the ratio of the total number of hops. The simulation shows that the improved algorithmunder certain conditions is better than the classical algorithm, the improved algorithm can reducethe error rate, improved the unknown node location.