• Joe
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When you show someone geolocated AR (augmented reality), generally the first natural practical application they suggest is to use it indoors, in order to enhanced the visit to a mall or airport. This sounds great but currently its not possible, at least not that easily. Let me explain…

The basics

Let’s expand on a subject that might be obvious to some of us on this field, but its not to most people. In order for any geolocated app to work, it needs to know its location. On a mobile device, the proper way to know this is by way of GPS. However GPS signals don’t work indoors, hence the phone defaults to triangulation (explained better below), which will depend on the fall back (i.e. No GPS signal) services the app is using (Google, Skyhook, Apple maps, etc). It will give the phone (hence the user) and approximative area on where the phone is. On the image below, the circle around the dot has two objectives:

Image taken from psychemedia on Flickr
  1. To facilitate the user the view of the his/her location (i.e finding the dot easier on the screen)
  2. To give an estimate on where the user is, because the triangulation location method used by these services its not as precise as the GPS the phone device has. Let it be stated, that a triangulation made by an operator can be very precise. But that’s the conundrum, Google, Apple nor Skyhook has direct access to operator’s networks and vice-versa. Honestly I don’t think neither party will want to share this info. So things stay as they are.

Why GPS signals don’t work indoors?

Because they are extraterrestrial signals! 🙂 A more serious answer is that for a signal in order to go through the atmosphere needs to be a very high frequency. These types of frequencies normally used by GPS and communication satellites are in the order of Ghz (gigahertz). Because they are so high frequency and because the GPS constellation of satellites are above the earth (far away, ok geeks, +22 thousand Kms), when these signals arrive to earth and our devices, they are indeed very weak. So we can’t possible ask them that after that long voyage, go throughout concrete and many other construction materials.

One way to eliminate this problem is to install GPS relays/repeaters on the venue. This is quiet feasible, the problem might be then (as always) justify the cost of installing the repeater vs. the benefits. After all, its not that people are claiming for indoor GPS within malls, in first place because they don’t know that there’s use for it (chicken and egg problem). Hence we can discard the installation of repeaters.

A-GPS (assisted GPS) exists to overcome these limitations, by way of the phone requesting its location to the cell tower, again this solution depends on the operator, meaning its not ubiquitous as a GPS signal might be, no matter how weak it is.


Fortunately many creative people are trying to tackle the problem, whether its by software or hardware. Junaio has for some time now, offered a workaround to this limitation by way of QR codes. Scanning these codes gives the Junaio browser immediate location aware, guiding the user of his/her surrounding. Granted this method implies:

  1. Create QR codes with the geolocation information. Later putting these QR codes all around the venue.
  2. People has to scan the QR code frequently all around the building

Its not an ideal solution, but its there.

Qualcomm comes to the rescue

Qualcomm its not the only company trying to solve this problem, but might be the closest one to popularize a solution. What they’re proposing is to put the location information on the WiFi signal itself. After all, we can agree WiFi is almost everywhere, so such a solution its more feasible to see mass adoption, contrary to other ones. Of course, Qualcomm proposal is that: a proposal, we still have to see if all this becomes a reality, we surely hope so, because we need to augment it 🙂

More info here.

Author: Joe