“…Nowadays, there are a large number of applications for ILBS in market. And researchers have carried out a large number of studies on indoor positioning technologies and developed corresponding indoor positioning systems, such as the infrared [ 1 ], ultrasonic [ 2 ] or sound [ 3 ], radio frequency identity [ 4 , 5 ] (RFID), ZigBee [ 6 ], Wi-Fi [ 7 , 8 ], Bluetooth [ 9 ], microelectromechanical systems (MEMS) sensors [ 10 ], ultra-wideband [ 11 ] (UWB), geomagnetic field [ 12 , 13 ], visible light [ 14 ], computer vision [ 15 ], pseudolites [ 16 ] (PL), etc. However, due to the complexity of the indoor environment, it is usually difficult to provide a satisfactory level of accuracy in most applications.…”