Abstract: Wireless Sensor Networks have emerged as one of the key research area since last few years containing various challenges. Determining the accurate position of nodes in sensor networks is one of those imperative and tedious tasks.Once the precise location of nodes has been established only then the required functions such as routing, forwarding, information broadcasting can be achieved. To achieve localization,we need some deployed nodes whose position is pre-known.These nodes are called anchor or landmark nodes. With the help of these anchors,location of sensing nodes are found out.This paper presents an analysis of various localization schemes and contrasts the traditional techniques with modern ones.

Keywords: Sensor networks, anchors, localization, range based, range free, mobile nodes