Improving GNSS carrier-phase tracking via oscillator g-sensitivity compensation

In this paper the influence of oscillator g sensitivity on carrier-phase tracking performance in a global navigation satellite-system receiver is examined. It is illustrated that the local oscillator can be a limiting factor in the tracking threshold when the receiver is subject to pedestrian or vehicular dynamics. A novel feed-forward compensation technique is presented, which draws upon the inertial measurement unit resources of the receiver to alleviate these detrimental oscillator-based effects. Performance evaluation considered live global navigation satellite-system signals, a range of consumer-grade oscillators, and both high-quality and Microelectromechanical systems (MEMS)-grade inertial measurement units, in both pedestrian and vehicular operating environments. The results show that the process-noise spectral density corresponding to the signal acceleration state of the Kalman-filter-based tracker can be reduced significantly with compensation. It is also shown that three-dimensional velocity error reduces from 0.17 to 0.06 m/s with compensation.