A more pressing issue for an application such as BuildingAnatomy is the accuracy of GPS in urban landscapes. In built up areas GPS accuracy was less than 70m whereas we estimate we need 0.5-1m accuracy to align a 3d model to a building façade. Our workaround was to enter the location manually using the Layar Settings page which is fine for testing but not a compelling solution in the field.
We have a few ideas about ways to overcome this. One involves setting up predefined vantage points (perhaps using QR codes [12]) to obtain an accurate GPS reading that could be used for viewing a point of interest from a known location or to calibrate the device. Another approach that has been adopted elsewhere [13] is to employ 3d image recognition techniques to accurately pinpoint the users location relative to known building footprints. We recommend further investigations into these techniques as clearly improve the accuracy of the device geo fix is crucial to many teaching and learning applications of AR.
