I came across this quote in an article on Indoor Navigation on the IEEE Spectrum website. I see where Professor Pahlavan is coming from. At Llama we’ve been exploring different indoor positioning solutions over the past six months after a pub conversation in which we discussed providing targeted content in museums based on a user’s location. We quickly learnt that this is a nut that many others have also been trying to crack.
So, what is indoor positioning?
Put simply, it is an alternative to GPS for inside buildings.
GPS is, more often than not, unavailable once you are inside a building. And at best it is only accurate to around 10m. This is fine for an outdoors environment, but not indoors – where a 10m error could easily locate you in a different room, building or on a different floor.
What is the difference between Indoor Positioning Systems (IPS) and Real Time Locating Systems (RTLS)?
As I started exploring the subject I kept coming across these two terms. They seem like they are used synonymously, but actually they are looking at location positioning from opposite perspectives.
IPS usually refers to a user with a smartphone navigating and receiving position-related content and services in real time.
RTLS is to do with locating people and things at a distance. This tends to involve RFID tags (Radio-frequency identification).
IPS is what we are interested in at Llama – for now.
Methods of Indoor Positioning
A variety of methods have emerged as solutions for indoor positioning with varying success. All of the methods below use technology that is available in smartphones.
Tapping into the near ubiquitous proliferation of Wi-Fi access points in urban areas, this method uses a ‘fingerprint’ made up of relative signal strengths of all the detectable wireless access points.
This method uses light pulses from LEDs that are manipulated by a microchip in the LED. The LED transmits information by flickering rapidly (too fast to be detected by the human eye) and this is detected by the smartphone camera which decodes the signal to determine the location.
Inspired by the way certain animals can detect their location based on local anomalies of the Earth’s magnetic field, this method uses a ‘fingerprint’ of magnetic field disturbance throughout a building.
As mentioned above, RFID tags (radio-frequency tags) are more frequently used for RTLS (real-time locating systems) than IPS. However, they can be used for IPS. When a phone passes very close to a tag it can trigger a transaction. If we know where the tag is we can then deduce the position of the person.
Beacon / iBeacon
Beacons are small standalone devices that use Bluetooth Low Energy technology to regularly transmit identifying information. A smartphone can detect the presence of beacons within range (typically up to around 50m) and make an approximation of distance based on relative signal strength.
iBeacon is Apple’s brand name for the Beacon technology which has been added to iOS7.
The inclusion of iBeacon is iOS7 has been a game changer for IPS. With iBeacon now easily accessible on iPhones, the iBeacon technology appears to be the most likely solution for IPS in the near future. A range of beacon hardware has become available in recent months – some of which we have been experimenting with.
In the coming posts I will describe how we are progressing with our beacons.