Bluetooth-based indoor positioning with fuzzy based dynamic calibration

Indoor positioning using readily available Bluetooth (BT) technology and Received Signal Strength Indication (RSSI) values on a BT node has been a goal of researchers for some time. However, the fluctuations of the RSSI values due to the nature of RF signals and the environmental changes lead to significant errors in the accuracy of the indoor positioning applications. This paper proposes a new approach based on monitoring variations of the received RSSI and dynamic calibration of the BT nodes to adapt to these variations. In order to further enhance the accuracy, a fuzzy logic unit has been designed to perceive the situations when the BT node is in proximity to one of the reference nodes available in an environment. Testing results show that the proposed scheme can significantly improve the performance of the indoor positioning compared to other known methods. Results show that the new approach is able to locate objects in the indoor environment with an average error of 1.27 m, which is sufficient for many indoor positioning applications.