At this meeting two of four University of Calgary winners of ION GNSS 2012 best presentation awards , Dr. Fatemeh Ghafoori and Laura Ruotsalainen, presented their papers to the Alberta Section. [download here, and here]
Fatemeh Ghafoori is a post-doctoral fellow in Geomatics Engineering, Schulich School of Engineering, at the University of Calgary. She received her M.Sc. in Digital Communication Systems and Technology at the Chalmers University of Technology, Sweden, and her Ph.D. in Geomatics Engineering at the University of Calgary, Canada. Her research interests focus on ionospheric scintillation effects on GNSS receivers.
In this project research is conducted to quantify ionospheric scintillation impact on GNSS services and operations in the Arctic region. Auroral and polar ionospheric scintillation events are chosen from a Canadian high-latitude GPS database and the observed real scintillation parameters are used to drive GNSS signal simulations. Simulated signals are processed using a software receiver and impact on observation quality is quantified in terms of loss-of-lock probability and tracking errors; number of satellites affected simultaneously is also determined. A generic carrier tracking loop is implemented to determine impact on low-cost single frequency (marine and aviation) receiver performance. Robust receiver settings are recommended to improve receiver tracking capabilities under scintillation conditions.
Laura Ruotsalainen is a research scientist at the Department of Navigation and Positioning at the Finnish Geodetic Institute and a PhD candidate in the Department of Computer Systems, Tampere University of Technology, Finland. She received her M.Sc. degree from the Department of Computer Science, University of Helsinki in 2003. Currently, she is a visiting researcher in the Position, Location And Navigation (PLAN) group, in the Department of Geomatics Engineering at the University of Calgary. Her doctoral research is focused on visual-aided seamless indoor/outdoor navigation.
A pedestrian navigation system has to be accurate, reasonably priced, easy to use and light to carry to be adopted into use. Smartphones are attractive platforms for the navigation systems due to their small size, low cost and diversity of sensors feasible for positioning. Pedestrian navigation is mostly needed in GNSS degraded and denied areas such as indoors and in urban canyons. Self-contained sensors function independently regardless of the environment by augmenting the radio positioning systems, like GPS or wireless radio sensors, using information of the motion of the user. The measurements from self-contained sensors in a smartphone are, however, noisy and biased and thus need some aiding. This paper presents a method of using measurements from consecutive images as a gyroscope and an odometer. The rotation of the camera is calculated from vanishing points and the change in the heading angle used as a gyroscope measurement. Using the tilt obtained from the vanishing point calculations the distance to the objects in the navigation environment is observed and the translation between consecutive images measured with image homography from the image points of the objects. The translation measurements are then used as measurements from an odometer.