GPS (Global Positioning System) is a well known technology used for tracking and navigating. Everyone that have used GPS knows that the signal is blocked when you are inside a house, in a garage or surrounded with tall buildings. IPS (Indoor Positioning System) is a technology used for positioning were GPS can not be used. The most common technologies for IPS are radio, infrared or ultrasound signals.
Lets have a quick look at the three different IPS technologies.
IPS based on radio signals can use WLAN or Wi-FI. Advantages using this: Low cost, exists a lot of places and covers large areas and could work across multiple buildings. The disadvantage is low accuracy.