|Abstract||In a wireless sensor networks, knowing each sensor location is essential for efficient management of the network. There are various geometric localization schemes have been proposed to identify the sensor location within the network. However, these schemes shows high localization error when we give priority to unsymmetrical distribution of radio signal and less deployment density of reference nodes (location aware nodes). In this dissertation, we have proposed four geometric constraint based range free localization schemes. We have also considered the different deployment scenarios such as static sensors-static anchors and static sensors and mobile anchor. Besides, we have consider the worst scenario of different performance evaluating parameters to authenticate the applicability of proposed schemes in terms of localization accuracy.