Nowadays, people spend most of their time in indoors environments for work and leisure, while using mobile computing devices such as smart phones, tablets and laptops. It is necessary to remotely determine the position of individuals and various items within complex indoor environments for location and relative navigation purposes. Some detection techniques have been introduced in a bid to provide indoor positioning solutions. These techniques employ Positioning System signals such as Radio-frequency identification, Wi-Fi, ultra-wide band, Bluetooth etc. However to effectively locate mobile gadgets indoors, most of these systems require installation of high-tech hardware and equipment within rooms, which usually has the disadvantages of: very high costs, high-energy consumption and limited precision. In this paper, we propose a hybrid indoor location system (HILS), which relies on low energy Bluetooth and ultrasonic technologies. HILS is a low cost and low energy consumption system that provides real time precise location of individuals and various items within complex indoor environments. HILS is based on the deployment of equidistant nodes on the ceiling, that communicates with mobile smart devices within the transmission range. The nodes are programmed to activate when a smart device enters within the broadcasting range and broadcast a Bluetooth RF beam on a periodic time-pace of 400ms. The smart device then determines its location using the three access points (nodes) with the highest signal strength. If the smart device can no longer reach an accurate location, it will automatically transmit three RF frames; by default, only three nodes will respond and each node will transmit an ultrasound Beep which the smart device receives using its microphone and then give feedback using algorithms. Test results showed that HILS can accurately locate devices within a range of 80cm in a real-world environment.
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