Precise Mass-Market Mobility
GPS 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:
- 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.
- Differential carrier-phase-based positioning is power hungry compared with standard code-phase positioning. On a mobile device, milliwatts matter.
- Lack of a killer app.