Indoor navigation fills the blanks that global positioning systems (GPS) leave. Since satellites don’t pick up well indoors, navigating indoors requires a separate system that relies on near field objects. Indoor positioning systems may use dead reckoning, fixed anchor nodes or magnetic positioning to identify user and object or destination locations.

1. No standard exists for an IPS system. Multiple systems are in the market that use acoustic, optical and radio technology.

2. Similar systems detect magnenometric information inside iron ore mines or steel structures.

3. An indoor positioning system requires trilateration, meaning three independent measurements used together to unambiguously pinpoint a location.

4. Marketing and sales use the gps for indoors to make purchasing easier. For example, Apple iBeacons lets you order donuts on your phone, then alerts the cashier when you enter the bakery. The cashier scans a QR code on your cell phone and your payment processes automatically from your e-wallet or linked credit card. According to Apple, its system can pinpoint locations from to two inches to 160 feet.

5. Beyond commercial applications, there are systems of indoor navigation for the military, such as Locata, accurate up to eight inches from its target, according to test results made public in 2013. Such systems help “grunts” navigate indoors or in urban caverns, for example, sewers.

6. Using Bluetooth and an app, a user can access indoor maps that let them navigate quickly through large, indoor areas like airports, football arenas, or shopping malls. A quick search for a destination, say a specific gate, produces a route result and a signal that guides them through the route. Some systems offer specialized navigation aid functions for physically disabled or sight-impaired users. These help users locate needed building elements like automatic doors, elevators, accessible bathrooms and the help/information desk for check out of power chairs or indoor scooters.

7. Using beacon technology, an IPS can provide automatic, “E-Z Pass” access to buildings. It can recognize authorized users as they approach the building. For added security, a building owner might add thumbprint or eye-scan recognition.

8. Commercial mapping services created the first indoor maps. Google chose London’s Wembley Stadium and Las Vegas’ Caesars Palace as some of its first projects.

IPS and indoor mapping provide two examples of wide-ranging applications of the Internet of Things. Using only their cell phone and its Bluetooth, users can connect with, interact with and communicate with objects in their home, office or during errands, and navigate through any indoor area they visit.