Table 2: Comparison of main indoor positioning technologies. UC: end user cost; IC: installation and maintenance cost; H: high; L: low; ML: multiple levels.

IPS Technology Approx. accu. Coverage Cost Strengths Weaknesses
IC UC

Technologies with signal encoding
[22] Infrared 57 cm–2.3 m RoomH L Cheap for user Sunlight interference
[23] VLC 10 cmBuilding (ML)H L Cheap for user, unintrusive Expens. infrast.
[24]Ultrasonic1 cm–2 mRoomH H Good precision Cost, interfer.
[25] Audible sound Meters RoomL L Low cost Low precision
[26] Wi-Fi 1.5 mBuildingL L Low cost, good precisionVulnerable to access point changes
http://research.nokia.com/news/11809Bluetooth 30 cm–meters BuildingL L Low cost, good precision Intrusive; needs signal mapping
[27] ZigBee 25 cm BuildingL H Could reuse infrastructure Low precision; user needs special equip.
[4]RFID 1–5 m RoomH L Very low cost passive side Very low precision
[28] UWB 15 cm BuildingH H High precision High cost

Passive technologies without signal encoding
http://www.indooratlas.com/ Geomagnetic 2 mL L No need for infrastructure, good precision Requires mapping
[29] Inertial 2 mL L Low cost, privateAccumulates error
[30] Ambient sound MetersL L Cheap, not intrusive Not accurate, sensitive to changes
[23] Ambient light 10 cm–metersL L Cheap Sensitive to sunlight and changes such as a bulb and a window
[9]Computer vision 1 cm–1 mL L Low cost, privacy if cellphone camera is used Sensitive to light conditions