“…Systems based on Wi-Fi, 2,3 Bluetooth, 4,5 UWB, 6 cellular networks, [7][8][9] or RFID 10 were proposed. Moreover, other sensors can also be used to estimate the position of mobile devices, including measurements of sound, ultrasound, 11 magnetic field, 12 cameras, light, 13 or inertial forces. 14 However, solutions based on radio signals seem to be most frequently proposed.…”