The recent technological developments in low-power electronics and wireless communication have increased the use of ad hoc wireless sensor networks for environmental monitoring and security applications. A typical network is a randomly distributed collection of scores of low-power wireless sensor nodes. Network localization is the process of estimating the location of each sensor in the network. Network localization is an imperative capability for the effective operation of wireless sensor networks. In this research project we explore an innovative approach to localization that uses an array of directional antennas, together with a node’s radio communications, to sense the bearing and distance between neighboring nodes. We also pursue a variety of computational methods to determine the best position estimator. We found that the proposed localization approach can measure the angle of arrival (AOA) with about 4 degrees mean absolute error and can determine distance between the transmitter and receiver with 5 feet mean absolute error using the prototype antenna array. In addition, the mean absolute distance error between the actual and estimated positions was found to be 14.5 feet (about 4.5 meters). Also, compared to other approaches, our approach can solve the network localization problem with fewer beacon nodes needed in the network, which means a significant reduction in hardware and software cost. Our findings demonstrate the feasibility of non-coherently using directional arrays in wireless sensor networks for determining angle from radio signal strength. The estimated angles, combined with either coarse distance information or a few known node locations, provide a solution for the network localization task.