A New Positioning Algorithm Of Sensor Nodes Based On Interference Of Waves

Wireless sensor networks (WSNs) will be one of most important new technologies in the future. Its development and extensive applications will surely bring great impact on human life style and also steer to industrial renovation. And compared with familiar wireless networks such as Mobile Communication Network,Wireless Local Area Network,Bluetooth Network,Ad hoc Network etc, WSN has a lot new properties and many research hotspots.A wireless sensor network (WSN) consists of a set of sensors that communicate with each other 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. The nodes are typically highly resource-constrained (processor, memory, and power), are prone to failure, have limited communication range. These characteristics present great difficult to large-scale sensor networks' localization techniques. This thesis focuses on self-localization problem in wireless sensor networks.First the thesis reviews of the localization problem in wireless sensor networks, introduces the fundamental principles of self-localization techniques, discusses the evaluation criterion of the performance and the taxonomy of wireless sensor networks self-localization algorithms, discusses the principles and characteristics of some representative localization approaches.Then the thesis proposes a new method of angulation of unknown nodes. Based on the theory of interference of waves, this method transforms the angle measurement to the easier frenquency measurement. In simply, the beacon node sends interference of waves and changes the frequency, in this processs, changing frequency of the composed waves intensity in different directions to the beacon node is different, i.e., the changing frequency of the composed waves intensity is small when the angle is small, and goes up with angle. According to this truth, unknown nodes can measure the angle to the beacon node. Finally, based on the new measurement of the angle of sensor nodes, the paper discusses about the positioning algrithm and does the experiment.This new method of angulation of unknown sensor nodes is simple and easy to use, compared to AOA, has lower request to the handware of sensor nodes and has higher precision. This angle measurement is new and suitable for the wirelesss sensor networks.