Indoor Positioning Systems are the underlying technology that enables a number of location based solutions, including:

  • Real Time Location Systems (RTLS)
  • WayFinding
  • Inventory Management
  • First Responder Location Systems

In order to build one of the solutions above, first by using indoor localization, the position of the object of interest must be determined, and that position is fed into the application software to make that information useful.

For systems that rely on indoor location tracking, a number of different technologies can be used, including the five options listed below.

Proximity Based Beacon Tags (Bluetooth Low Energy)

AirFinder is an example of a proximity based beacon tag based indoor positioning system technology. Here, simple and inexpensive tags transmit their identification to a number of “readers” which pass this identification and the signal strength to a backend system that calculates the position.

The benefit of Proximity Based Systems is that the are the lowest cost systems to accomplish simple indoor localization.

» Learn more: 5 Things to Consider When Selecting Healthcare RTLS

WiFi Based Tags

In a WiFi based system, tags are WiFi transmitters which send simple packets to a number of WiFi access points in a facility. These access points report the time and strength of that reading to a backend which uses algorithms to compute position. These system can be very accurate, but require location enabled WiFi access points, and costly WiFi based tags.

Ultra Narrow Band

UNB systems are really cool. In an UWB based indoor location tracking system, inexpensive UWB tags “chirp” out a very weak and wideband signal which is received by three or more readers. Because the UWB signal is very wideband, the accuracy of the location information is very good.

These tags can be inexpensive and the location is probably the most accurate of any system out there. The drawback is that because of the limited range of the tags, many expensive readers are needed to be installed in the area of interest.


A number of new indoor position systems have come onto the market recently that use ultrasonic pulses from tags to locate them within an indoor environment. It’s pretty much like it sounds (ha!), but the benefit of using sound is that you need less signal bandwidth to resolve multipath because the speed of sound is so much less than the speed of light.


IR based indoor location systems use IR light pulses (like a TV remote) to locate signals inside of a building. IR readers are installed in every room, and when the IR tag pulses, it is read by the IR reader device. It is a near foolproof way of guaranteeing room level accuracy. The drawback is that every room needs a wired IR reader to be installed in the ceiling. It is commonly used in new hospital construction.

There are a few more technology types out there that enable indoor positioning systems, but these are the main ones. Each technology type has advantages, disadvantages, and unique costs. Anyone looking at indoor location tracking applications should understand the implications of the underlying technology.

Healthcare RTLS

Written by Brian Ray

Brian is the Founder and CTO of Link Labs. As the chief technical innovator and leader of the company, Brian has led the creation and deployment of a new type of ultra long-range, low-power wireless networking which is transforming the Internet of Things and M2M space.

Before starting Link Labs, Brian led a team at the Johns Hopkins University Applied Physics Lab that solved communications and geolocation problems for the national intelligence community. He was also the VP of Engineering at the network security company, Lookingglass, and served for eight years as a submarine officer in the U.S. Navy. He graduated from the U.S. Naval Academy and received his Master’s Degree from Oxford University.