Arc Heart-based Wireless Sensor Network Node Positioning Algorithm Research

Wireless sensor network is a hot technology bringing huge influence to life style of human in 21 century following Internet, which is of great application value and foreground in many fields (e.g., military, industrial, civilian, etc.). A wireless sensor network (WSN) consists of a set of sensors that communicate in an ad hoc manner. In this kind of network, sensor nodes are deployed randomly and densely in the area to be monitored. The precise positions of the sensors may not be known in advance; but to process information, it is important to know where the data comes from. So, determining the positions of sensors is a key problem in many applications.This paper presents a new distributed positioning algorithm for unknown nodes in a wireless sensor network. First, assuming that there are some anchor nodes in WSN, the positions of which are already known. Then geometric relationships and communication constraints among the unknown node and the anchor nodes are founded based on the assistant plane coordinates system and the radio-communication range of sensors. A circular belt containing an unknown node is obtained using information about the anchor nodes that are in radio range of the unknown node, based on the geometric relationships and communication constraints among the unknown node and the anchor nodes. Then, the centroid of the circular belt is taken to be the estimated position of the unknown node. Since the algorithm is based exclusively on connectivity, range-free and distributed, it is very simple, and the communication loads as well as computational loads are very small. Furthermore, the algorithm is robust because neither the failure of old unknown nodes nor the addition of new unknown nodes influences the positioning of unknown nodes to be located. These features make this algorithm suitable for all sizes of low-power wireless sensor networks. In addition, the lack of a generally applicable positioning algorithm for WSNs motivated us to devise a more efficient one to fetch up the blank of algorithms which are used to position the unknown nodes in a three-dimensional WSN. A new distributed positioning algorithm that is based on the centroid of a three-dimensional graph is devised. The constructing method of a three-dimensional graph containing an unknown node is researched based on the geometric relationships and communication constraints among the unknown node and the anchor nodes. And the centroid of the three-dimensional graph is taken to be the estimated position of the unknown node. This new algorithm is used to determine node locations in three-dimensional WSNs to accelerate the application and development of WSNs.A theoretical analysis and simulation results show that the algorithm based on the centroid of circular belt does not produce any cumulative error and is insensitive to range error, and that a change in the number of sensor nodes does not affect the communication or computational load. These features make this algorithm suitable for all sizes of low-power wireless sensor networks.