RTLS Systems Designing Approach Using Beacon Technology

This article presents extensive research and analysis of the location capability of Bluetooth low energy (BLE) in designing real-time location systems (RTLSs). The main assumptions for the proposed approach are to optimize precision of location to less than 2 m, its reach up to 20 m, and system response time not exceeding 5 s. In addition, the system should be characterized by low energy consumption, and low construction and operating costs. In order to meet the above assumptions, extensive studies of received signal strength indicator (RSSI) radio signal parameters and time interval (TI) parameters were carried out. The tests were performed at a distance of 1 to 20 m for different types of emitter (beacon)–scanner pairs (microprogrammable platform). Detailed studies of location accuracy were performed using several nonlinear regression methods. The selection and assessment of the reliability of the approximating models was based on the information criterion measures and cross-validation. The influence of the training set size and the test set size on the adopted model’s reliability was examined. Based on TI values, predicted response time was estimated for real-time localization, and the relationship between system dynamics and localization accuracy was investigated.