An Improved Weighted Centroid Localization Algorithm For Wireless Sensor Networks

Wireless Sensor Networks (WSN) has great application such as surveillance andtarget tracking. In recent year, smart sensor node, which is small size, inexpensivewhile with processing ability, have developed for a wireless communication network tofulfill desired task by great number of sensor nodes. Sensor node self-Localization is afundamental issue, it is able to provide necessary position information for routing,monitoring and target tracking in many application. Therefore, It has attracted greatamount of attention of researches and make great advancement.The location techniques for WSN can be divided into two categories:Range-based approaches and Range-free approaches. The former one has betteraccuracy, but requires additional hardware at the sensor nodes. The latter one has loweraccuracy and requirement of hardware.For advantages and disadvantages of range-based and range-free localizationalgorithm, the thesis mainly focuses the investigation on combination of ranged-basedand range free localization algorithm for WSN, which includes three aspects as follow.First of all, we proposed a range-based localization algorithm, i.e., double anchornodes localization algorithm when nodes density is sparse in terms of difference ofrange and radio radius and between two anchor nodes. Secondly，when density is highwe proposed weighted centroid localization based on multiple double nodes. Thisapproach firstly select multiple double nodes for coordinate localization estimate. Thenusing weighted centroid localization to enhance localization accuracy. Thirdly,introducing relative receive signal strength indicator as weight fro calculate coordinateof unknown sensor nodes. The approach adapts moving average method in time weight.We applied it to WCL space. Simulation shows, when nodes density is sparse,compared to traditional centroid localization and weighted centroid localizationalgorithm, double anchor algorithm will enhance accuracy of localization; whendensity is high, weighted centroid localization based on double anchor nodes isemployed can not only improve accuracy localization but also overcome errorgenerated from noise; the localization accuracy of weighted centroid localization basedon relative RSSI Superior to the traditional CL and the WCL algorithm.