These two new blog articles from the IESSG were published on the GPS World Tech Talk Blog:
Aiding Indoor Pedestrian Navigation with Building Heading
January 12th, 2011 by Khairi Abdulrahim
By K. Abdulrahim, C. Hide, T. Moore, C. Hill
This article presents a simple solution to one of the main challenges of indoor pedestrian navigation. Many researchers have shown the benefits of using low cost shoe mounted IMUs, but the major drawback of these systems is the rapid and dramatic growth in heading drift error. The method proposed constrains this heading drift by simply using the orientation of buildings (derived from aerial imagery). Using this approach a series of real world trials have demonstrated that it is possible to return to a known point with a position error of just 0.1% of the total distance travelled, whilst using only a self contained low cost IMU.
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January 11th, 2011 by Chris Hide
Chris Hide, Terry Moore and Marcus Andreotti, IESSG, University of Nottingham
Tom Botterill, University of Canterbury, New Zealand
Introduction
Low cost MEMS gyros and accelerometers are often considered as a potential solution for indoor navigation, but the reality is that such sensors are only sufficient to provide useful positioning for very short periods of time. This is due to sensor errors such as biases and scale factor errors that are not necessarily constant over time. Low cost MEMS sensors have recently been demonstrated to provide useful levels of performance through innovative ideas such as mounting an Inertial Measurement Unit (IMU) on a user’s foot and using zero velocity updates every time a user takes a step. Another form of frequent measurements to correct the IMU comes from using computer vision. Cameras can be used to provide measurements such as translation and rotation between frames by tracking features contained in the image. This article builds on work from Hide, C., Botterill, T., & Andreotti, M., 2009, and looks at the use of aiding measurements from a camera attached to an IMU where the user is walking with the device held out in front of them with the camera pointing towards the ground. Some smartphones already contain these sensors so this method could be a viable form of navigation in the future. Read the rest of this entry »