Moustafa Alzantot and Moustafa Youssef at Alexandria University in Egypt have developed an app that crowdsources data from smartphone sensors to construct indoor floorplans automatically. It's called CrowdInside.
It uses a variety of sensors (GPS, wi-fi, accelerometers, etc.) to gather data, but regularly updates the data with a kind of ground truthing.
The basic technique is dead-reckoning using an accelerometer as a pedometer and the magnetometer as a direction finder. The number of steps in a specific direction give a rough idea of the distance walked.
The problem, of course, is that dead-reckoning is notoriously susceptible to errors, which build rapidly in time. To get around this, the system needs to be constantly re-calibrated using points at a known location.
This is the clever part of the system. Alzantot and Youssef start by using the location where GPS data becomes unavailable to determine the entrance to the building. That gives a starting point for the dead-reckoning.
Next, they use the sensor data to spot when the users are in an elevator, using an escalator or simply walking up or down stairs. In each case, the movement produces a unique pattern of acceleration that is different from walking and so makes them easy to spot.
It's unclear how or if the app will be marketed.
- Tech Review via reader Kevin
The mobile platform company now known as Unwired Planet, which most of us knew as Openwave, is suing Google and Apple for patent infringement including infringement of LBS and related patents in Google Maps, Safari and Apple Maps. it seems Unwired Planet hasn't done too well of late and this is a way to bring in some revenue, per analysts. Microsoft has paid to use some of Openwave's patents in the past.
MIT researchers have built a wearable sensor system that automatically creates a digital map of the environment through which the wearer is moving. The prototype system, described in a paper slated for the Intelligent Robots and Systems conference in Portugal next month, is envisioned as a tool to help emergency responders coordinate disaster response.
- MIT News