Date Added: Jul 2012
For variety of applications of sensor networks like tracking, monitoring, intrusion detection, geographical routing etc, localization plays a critical role. Any information from a remote node without its location is of less use in most of these applications. For small sized nodes with limited resources and densely distributed nodes, accurate and low cost localization is a critical issue. An efficient localization scheme exploits inherent collaborative nature of nodes in a sensor network to identify the location of nodes. More than 50 localization schemes exist as of now. Contribution of this paper is to present various localization schemes based on various measurement techniques and algorithms thereof. Based on factors like accuracy, communication cost and feasibility in three dimensional scenarios is discussion.