Recent Advances in Wireless Indoor Localization Techniques and System

Table 3

Comparison of common position systems used for localization.

System	Accuracy	Principles used for localization	Coverage	Power; consumption	Cost	Remarks
GPS	6 m–10 m	ToA	Good outdoor Poor indoor	Very high	High	(1) Satellite based Positioning.; (2) Processing time and computation is slow.
Infrared	1 m-2 m	Proximity, ToA	Good Indoor	Low	Medium	(1) Short range detection.; (2) No invasion of multipath.
WiFi	1 m–5 m	Proximity, ToA, TDoA, RSSI Fingerprinting, and RSSI theoretical propagation model	Building level (outdoor/indoor)	High	Low	(1) Infrastructure available everywhere.; (2) Initial deployment is expensive.; (3) Multipath susceptible slightly.
Ultrasound	3 cm–1 m	ToA, AoA	Indoor	Low	Medium	(1) Sensitive to environmental.; (2) No invasion of multipath.
RFID	1-2 m	Proximity, TOA, RSSI theoretical propagation model	Indoor	Low	Low	(1) Real time location system.; (2) Response time is high.; (3) Manual programming.
Bluetooth	2 m–5 m	RSSI fingerprinting and RSSI theoretical propagation model	Indoor	Low	High	(1) Data transfer speed is high.; (2) Limitation in mobility.
ZigBee	3 m–5 m	RSSI fingerprinting and RSSI theoretical propagation model	Indoor	Low	Low	(1) Low data transmission rate.; (2) Nodes are mostly asleep.
FM	2 m–4 m	RSSI fingerprinting	Indoor	Low	Low	(1) Less susceptible to objects.; (2) Signal is strong; due to this, it covers large areas.

cm: centimeters; m: meters.