Open-Source Hardware-Based Three-Dimensional Positioning Device for Indoor Measurement and Positioning

Abstract

Indoor private (local) wireless networks are considered key enablers for the industrial Internet of Things (IIoT). To ensure that a private network satisfies its own requirements and guarantees coverage, it is important to accurately measure the radio performance at the accurate position to further optimize the network. Additionally, as carrier frequencies increase, cellular network-based positioning becomes increasingly important, as it enables more accurate positioning. For example, centimeter-level accuracy is expected in beyond 5G systems owing to the sub-THz band carrier frequency. To accurately compare and assess various cellular network-based positioning methods, positioning devices, which can move along the same trajectory more accurately than at the centimeter-level, are required. To this end, we implemented a three-dimensional (3D) positioning device developed from open-source hardware, which is generally used to implement computer numerical control (CNC) machines and 3D printers. The implemented 3D pointing device is cost-effective and portable and can be freely configurable and resized in one, two, and three dimensions owing to the use of open-source hardware. The received signal strength indicator (RSSI) employing the LoRa module can be obtained using the implemented device. Using a very low carrier frequency system, it is possible to accurately measure the RSSI variations due to multipath propagation. After demonstrating the reproducibility of the data, the effectiveness of the implemented device was confirmed by showing that the RSSI variation and fading correlation coefficient are close to the Rayleigh fading variation.