Indoor Positioning System

Why there is need of Indoor Positioning system?

1.       GPS (Global Positioning System) is used for outdoor Global Positioning.

2.       GPS requires connection with GPS satellites for positioning.

3.       For positioning inside building, PS satellite signals are weakened by roofs or wall of buildings.

4.       In such cases we need to have own positioning system called IPS (Indoor Positioning System)

How IPS (Indoor Positioning System) is different from GPS?

IPS works on the same lines as GPS except you use different signals than GPS satellites.

What are the ways to achieve Indoor Positioning System?

1.       Wi-Fi Triangulation – Use existing Wi-Fi Routers as signal sending devices to accurately pinpoint location inside a building.

·    Every Wi-Fi router sends signals in Circular pattern.

·         Device which falls in the range of Wi-Fi router can read the signal strength without even connecting to the router.

·         Generally Wi-Fi signal strength captured by device is related to distance of the device from the router given as following mathematical formula –

‘S’ signal strength captured by device from a certain Wi-Fi router located at a distance ‘R’ is represented as

S α R²

To accurately get position of a device using Wi-Fi Router, with the help of geometry we can say that

                Three circles intersect in one and only single point.

Thus if a device is surrounded by at least three Wi-Fi routers we can get the fingerprint of the device i.e. device location with reference to the signal strength from all such Wi-Fi routers.

Let’s simplify this using a diagram :

With routers this will be like –

2.       Location Triangulation using Beacons dedicated for our use.

·         Wi-Fi triangulation technique uses existing Wi-Fi router which are basically not setup for positioning.

·         So we can have dedicated signal emitters for our location systems which are called as Beacons.

·         Rest goes same with this type of system

3.       Other sensors to uniquely fingerprint a location inside building like – Magnetometer

·          This is unique technique but rather difficult to design and manage.

·         Wi-Fi Triangulation and Beacon techniques rely on external hardware setup but this system is completely based on device itself.

·         If you are using magnetometer, basic idea is Earth magnetic field can be measured at any location on earth by using Magnetometer and which is unique with respect to the building or structure you are in.

·         This way we can create fingerprint of location inside a building which is unique in itself.