Indoor Positioning System

Indoor Positioning Systems (IPS) locate and track objects in buildings. All systems apply wireless concepts or optical tracking, some systems apply ultrasound. The located objects shall be tagged with labels, tags, tokens or transponders to enable locating or positioning. Examples of tagged objects are for example patients in any type of care or equipment in any type of hospital.

Special examples of discovered objects are people confined in burning buildings.

Outdoor systems are of comparable design, however do not oiffer special features for indoor usage, as efor example detection under avalanches or cooperative locating of soldiers in open air on a battlefield. .

The design of some of the known systems of this type is functionally equivalent to RTLS or Real time locating systems according to ISO?/IEC 19762-5 ans ISO/IEC 24730-1. However, many designs just report the location of the active unit. Some of the systems do not change a position nor report a location of any other object but their own location. Some of the systems have no specified latency to provide a location report. For more detailedinformation on this topic refer to the main article on Real time locating systems.

Global Positioning Satellite Systems (GPS or GNSS) are not suitable to establish indoor locations, since microwaves will be attenuated and scattered by roofs, walls and other objects. To overcome such conditions, an IPS will make use of uses local points of reference with wireless, infrared, or ultrasound transponders.

Radio communication
There are several approaches with wireless communication for indoor locating. All theses systems suffer from the problem that radio frequencies will multiply interfere with dielectric and metallic surfaces and cause multipath propagation. The mandatory requirement is to improve performance with repetitive locating to form tracks and to conquer faulty measurements with qualified mathematics.

Non radio communication
Infrared and ultrasound transmission is useful in confined contiguity where radio frequencies will possibly interfere with critical equipment.

Common technologies

 * Ultrasound Identification (USID)
 * Infrared (IR)
 * Real-time locating (RTLS)
 * Ultra-wideband (UWB)
 * Wi-Fi