If you want to use the Global Positioning System (GPS) you need visual contact to several satellites, which is not always given. In outdoor areas it can be interrupted by trees, clouds, tunnels or skyscrapers. Indoors there is hardly a chance to receive GPS signals. Moreover, with GPS it is not possible to determine the floor that a device or person is located on inside a building.
For this reason, other technologies are used indoors. The most common solutions are positioning with Bluetooth Low Energy (BLE) beacons or Wi-Fi in combination with smartphone sensors. With these technologies, the position of an end device can be determined and various applications such as indoor navigation are possible.