The word ubiquitous means anywhere. Ubiquitous positioning, as the name implies, is the provision of continuous positional information of a device in both indoor and outdoor environments. Ubiquitous positioning technologies include, but not limited to, for example, Global Satellite Navigation Systems (GNSS), cellular and WiFi networks, Radio Frequency Identification (RFID), Ultra Wide Band (UWB), ZigBee, and their integrations. The diagram shows the integration of GPS and ZigBee technologies  for ubiquitous positioning inside the PolyU campus. Since the area is surrounded by tall buildings, although GPS can provide positional information in the outdoor environment, the positions have much deviation from the actual path. ZigBee technology can be used to improve the positioning accuracy in the outdoor-to-indoor transition, and  provide position information inside the building.