Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished

Modern cell phone hardware, due to its integrated peripherals, provides a low cost intelligent controller for use in the navigation of an Automated Guided Vehicle (AGV). Most commercial AGV’s use proprietary hardware which is expensive to replace and also difficult to maintain. Using industrial hardware components combined with Android mobile platforms could provide a low-cost alternative. This would be easier to maintain, using existing in-house factory maintenance knowledge. A prototype AGV was designed and developed based on an integrated system between an industrial Programmable Logic Controller (PLC) and an Android operating system mobile platform. This system utilises the mobile platforms integrated Global Position System (GPS) or video camera as tools for navigation. Experimental tests were performed to determine whether the prototype can navigate a predefined course by making use of GPS and camera line following algorithms. The accuracy of the line following algorithm was influenced by the speed at which the research AGV moved. Mounting the Android camera higher above the ground improved the vision and therefore accuracy of the algorithm. The GPS algorithm successfully navigated to various waypoints. The accuracy of the implemented GPS unit on the Android device is its limitation. The research unit was only capable of reaching a waypoint consistently within a three-metre radius.

<p>The need for an aviation navigation system is established from examining the phase out of current systems and the delay in the development of replacement systems. The systems engineering approach has been applied to ensure that a capable system is developed. After establishing the need, two GPS based methods of creating an aviation navigation system are examined. A system based on the differential GPS method is chosen as the most feasible.</p> <p> The functional analysis, operational requirements and maintenance concept are defined based on the differential GPS choice. A conceptual system design is then described for each system element, the ground beacon element and the aircraft element. The allocation of requirements, element architecture and element reliability are examined in the conceptual design.</p> / Master of Science

<p>With continuing advances in technology, the market for vehicle navigation systems is expected to grow over the next several years. The systems engineering process is applied to ensure that an effective system is developed. After the need is established, four methods of implementing a vehicle navigation system are described. A system employing differential GPS to determine the location of the vehicle is chosen to be the most feasible approach. Based on this choice, the operational requirements and maintenance concept are defined. Possible design approaches are then discussed. A terrestrial radio link is selected over a satellite link to transmit the differential corrections to users. Finally, an analysis is performed to estimate the number of reference stations that will be required to implement the system. The results can be used as a guideline to determine the potential cost of providing a differential GPS service.</p> / Master of Science

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Data from a Coarse Acquisition (C/A) Global Positing System (GPS) map-grade receiver were evaluated to assess the accuracy of differentially corrected points. Many studies have focused on the accuracy of GPS units under ideal data collection conditions. Ideal conditions allow the collection of data with four satellites (3D mode), yet field data conditions are often less than ideal. Four satellites may not always be in view because of mountainous topography, heavy forest cover, or other obstructions which block satellite signals from the receiver. This study examines GPS accuracy when four satellites are not available, instead collecting data with only three satellites (2D mode). 3D GPS points compute four unknowns: x, y , z, and clock error. In comparison, 2D GPS points are less accurate as only three unknowns are calculated: x, y, and clock error. Elevation (or z) is not computed for 2D points, causing increased error in the horizontal (x, y) measurement. The effect of elevation was evaluated on 234 2D GPS data points. These points were collected and corrected at elevation intervals of true elevation, +-25 meters, +- 50 meters, and +-75 meters. These 2D points were then compared to surveyed points to measure the effect vertical error has on horizontal accuracy. In general, the more error in the vertical estimate during correction, the greater the horizontal error. / Master of Science

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No description available.