Node localization is important parameter in WSN. Node localization is required to report origin of events which makes it one of the important challenges in WSN. Received Signal Strength (RSS) is used to calculate distance between mobile node and reference node. The position of the mobile node is calculated using Multilateration Algorithm (MA). Extended Kalman Filter (EKF) is utilized to estimate the actual position. In this paper, the implementation and enhancement of a tracking system based on RSS indicator with the aid of an Extended Kalman Filter (EKF) is described and an adaptive filter is derived.