Localization Systems based on wireless communications are required to complete the deployment of reference nodes and it is essential to deploy three or more reference nodes before providing localization service. Also, It is difficult to provide accurate direction to users because of accumulated error of inertial sensor with time and influence of external magnetic field. This paper presents the localization system for estimating relative coordinates without pre-deployment of the reference nodes based on UWB(Ultra Wide Band) ranging communication. The proposed localization system which consists of a mobile node composed of three nodes estimates relative coordinates of the reference node and azimuth. Also, In the process of estimating relative coordinates of the reference node, errors are minimized through a RE (Rounding Estimation) technique and Kalman filter. Experimental results show the feasibility and validity of proposed system.