Wireless Sensor Network Positioning System Design And Implementation

Wireless sensor network node positioning technology has a very importantapplication, the premise of the correct position monitoring events is the correctlocation information of the node itself. The correct positioning of the node itselfcan determine the correct position of the monitoring events. The node itselfpositioning is to determine its own position in the case of a small number ofknown node, according to the certain positioning mechanism. Most of theexisting location algorithms are the simulation node system in a simulatedenvironment, get the accuracy of the algorithm, simulation experiment canreflect the positioning effect of algorithm theory, but in the actual applicationlocalization algorithm will be affected by many factors, simulation method cannot simulate all influencing factors completely, so the positioning system basedon sensor networks node development is very necessary.This paper uses iris nodes of Crossbow Company and TinyOS softwareplatform to establish three positioning system prototype, and verify theperformance of directly RSSI location algorithm, improved RSSI locationalgorithm and weighted centroid location algorithm.First based on RSSI localization algorithm to develop the standard RSSIpositioning system, the system is written in NesC and implements the RSSIlocalization algorithm, and burns it to the corresponding node. Unknown nodeobtains three different RSSI values by communication between the three knownposition coordinate value of the node and the unknown node, using the wirelesssignal attenuation model to estimate the distance the three beacon nodes and theunknown node. Combing known node position coordinate values calculate theposition coordinate values of the unknown node.Second based on improved RSSI localization algorithm to develop theimproved RSSI positioning system, the system is written in NesC andimplements the RSSI localization algorithm, and burn it to the correspondingnode. Unknown node obtains five different RSSI value by communicationbetween the five known position coordinate value of the node and the unknown node, unknown node retain or discard the data determine by the node ID number.Using four received RSSI value to calculate the location path attenuation indexvalues and the closest distance to three known nodes, combining with theknown node position coordinates to calculate unknown coordinate values.Once again based on improved RSSI localization algorithm to develop theimproved RSSI positioning system, the system is written in NesC andimplements the RSSI localization algorithm, and burn it to the correspondingnode. Unknown node obtains three different RSSI values by communicationbetween the three known position coordinate value of the node and theunknown node. Combing known node position coordinate values calculate theposition coordinate values of the unknown node.