Chai and Du propose a triangulation-based algorithm based on received RSSI value
Chai 2016. First, the RSSI value is preprocessed by removing outliers and calculating a moving average. Next, a calculated distance is determined from the pre-processed RSSI value, and an actual distance is calculated via Kalman filtering. Finally, triangulation is used to determine the actual location of the mobile device using the distance calculations from three or more BLE beacons. This resulted in a positioning error of 0.2 to 0.4 meters.