As the demand for indoor localization increases, several ultrawideband (UWB) localization systems are proposed and evaluated. The most difficult challenge for positioning is to find the simplest and most accurate indoor localization method. In this paper, a method of a 2D UWB indoor localization system is presented, allowing to improve the accuracy of angular measurement using a sliding window correlation method. The proposed architecture is simple, and the position of a tag is determined by the relative range and angle from the dedicated localization base station. The experimental results show that the proposed method can achieve high accuracy in estimating position and angle