A carrier phase reconstruction technique is presented as an enabler for low-power centimeter-accurate mobile positioning. Accurate carrier phase reconstruction permits the duty cycling of a Global Navigation Satellite System (GNSS) receiver whose outputs are used for precise carrier-phase differential GNSS (CDGNSS) positioning. Existing CDGNSS techniques are power-intensive because they require continuous tracking of each GNSS signal’s carrier phase. By contrast, the less-precise code-ranging technique that is commonly used in mobile devices for 3-to-10-meter-accurate positioning allows for aggressive measurement duty-cycling, which enables low-power implementations. The technique proposed in this paper relaxes the CDGNSS continuous phase tracking requirement by solving a mixed real and integer estimation problem to optimally reconstruct a continuous carrier phase time history from intermittent phase measurement intervals each having an ambiguous initial phase. Theoretical bounds on the probability of successful phase reconstruction, corroborated by Monte-Carlo-type simulation, are used to investigate the sensitivity of the proposed technique to various system parameters, including the time period between successive phase measurement intervals, the duration of each interval, the carrier-to-noise ratio, and the line-of-sight acceleration uncertainty. Results indicate that coupling a GNSS receiver with a smartphone-grade inertial measurement unit enables reliable phase reconstruction with phase measurement duty cycles as low as 5%.

Cite and download the paper:
K.M. Pesyna Jr., Z.M. Kassas, R.W. Heath Jr., T.E. Humphreys, "A Phase-Reconstruction Technique for Low-Power Centimeter-Accurate Mobile Positioning," IEEE Transactions on Signal Processing, 2014.