“…However, GNSS does not work well indoors due to the high attenuation and complex reflections of electromagnetic waves in buildings. To determine the location of mobile devices in an indoor environment, it is possible to use data from various supporting technologies such as WiFi [ 1 , 2 , 3 , 4 ], Bluetooth [ 5 ], RFID (Radio Frequency IDentification) [ 6 ], ZigBee [ 7 ], MEMS (Micro-Electro-Mechanical Systems) sensors [ 8 , 9 ], UWB (Ultra-Wide Band) [ 10 , 11 ], geomagnetic field [ 12 , 13 ], LiFi (Light Fidelity) [ 14 ], and acoustic signals [ 15 , 16 , 17 , 18 ].…”