An RSSI gradient-based AP localization algorithm

Recent rapid rise of indoor location based services for smartphones has further increased the importance of precise localization of Wi-Fi Access Point (AP). However, most existing AP localization algorithms either exhibit high errors or need specialized hardware in practical scenarios. In this paper, we propose a novel RSSI gradient-based AP localization algorithm. It consists of the following three major steps: firstly, it uses the local received signal strength variations to estimate the direction (minus gradient) of AP, then employs a direction clustering method to identify and filter measurement outliers, and finally adopts triangulation method to localize AP with the selected gradient directions. Experimental results demonstrate that the average localization error of our proposed algorithm is less than 2 meters, far outperforming that of the weighted centroid approach.