handGPS chipsets are getting smaller, cheaper, and more energy efficient. They are now ubiquitous in smartphones and tablets, enabling a host of location-based services. But the underlying positioning accuracy of consumer-grade GPS receivers has stagnated at approximately 2-3 meters.  We are engaged in bringing about the next revolution in consumer-grade mobile positioning, which will take us to centimeter accuracy.  The challenges of cm-accuracy on consumer devices are daunting:

  1. The GPS antennas on mobile handsets and tablets are little better than smashed paper clips. Their poor quality (15-20 dB below that of even a cheap patch antenna and dismal multipath mitigation) makes it extremely challenging to extract carrier phase measurements accurate enough for fast fixing of the integer ambiguities that arise in the carrier-phase differential technique. And mobile users are impatient: they may be persuaded to wait 30 seconds for a cm-accurate position fix, but only a resolute few would hold out for longer. 
  2. Differential carrier-phase-based positioning is power hungry compared with standard code-phase positioning. On a mobile device, milliwatts matter.
  3. Lack of a killer app.

We are working on innovations to meet these challenges. The most promising of these innovations exploits a mobile device’s camera in a near-optimal combination of visual SLAM and centimeter-accurate carrier phase differential GPS adapted for mobile devices. This combination will produce not only precise precision for mobile devices but a complete and precise pose (position and orientation), which will be a key enabler for convincing mobile augmented reality (AR).  We believe that video-see-through AR built on this technology has the potential to become a must-have application for future mobile devices.

Projects:

Recent Publications: