Petovello, MarkLachapelle, GérardBellad, Vijaykumar2015-12-072015-12-072015-12-072015Bellad, V. (2015). Intermittent GNSS Signal Tracking for Improved Receiver Power Performance (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26614http://hdl.handle.net/11023/2667Power consumption is critical in battery-operated devices using GNSS receivers. Modern day receivers track satellite signals from multiple constellations to achieve a better position performance making power conservation critical. Receivers in battery-operated devices employ intermittent signal tracking (or cyclic tracking) to conserve power. This research investigates various aspects of intermittent tracking and analyze the positioning and tracking performance with different duty cycles and solution update intervals in stationary and kinematic cases. Although power conservation is important it is preferable to achieve position accuracy equivalent to that of a continuously tracking receiver when operating in intermittent tracking mode, known as “feasibility” in this research. However, pseudorange accuracy and in turn position accuracy depend on the ability of signal tracking loops to converge during the receiver active period. Predicting code phase and Doppler values over the receiver sleep period can help to achieve this. The first part of this research identifies code phase and Doppler parameters as the factors influencing intermittent tracking operation, proposes a vector-based approach to improve their estimates at the end of sleep periods and provides a theoretical framework to determine the feasibility of intermittent tracking. The signal parameter errors at the end of sleep periods, length of the receiver active periods and the tracking loop transient response determine the feasibility. The amount of power saving can be as high as 60% to 70% in typical open sky kinematic cases with a longer solution update interval of 5 s. The second part of the research investigates intermittent tracking in weak signal environments. Doppler uncertainty during the receiver sleep period is identified as the limiting factor when longer coherent integration is used and a method is proposed to overcome this challenge. The last part of the research explores the use of inertial sensor aiding for improving intermittent tracking performance. A MEMS IMU (representative of very low power modern day IMUs) is used to assist tracking and improve power performance through GPS/INS integration. The inertial aiding does not improve the code phase estimation accuracy during the sleep period significantly; however improved Doppler estimation makes shorter duty cycles feasible.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Engineering--Electronics and ElectricalGeotechnologyGNSS receiversPower savingIntermittent trackingdoctoral thesis10.11575/PRISM/26614