Date of Award
Master of Science in Electrical Engineering
Department of Electrical and Computer Engineering
John F. Raquet, PhD
The accuracy and worldwide availability of the Global Positioning System (GPS) make it the dominant system for navigation and precise positioning. Unfortunately, many situations arise in which GPS may not be adequate, e.g., urban navigation. This research evaluates the navigation potential of the National Television System Committee (NTSC) broadcast signal using a time-difference-of-arrival (TDOA) algorithm. TDOA measurements are made using NTSC broadcast signals collected from low and high multipath environments. These measurements are then used to evaluate the severity and dynamic effects of NTSC broadcast multipath signals. Three data reduction algorithms were developed--one that modifies the classical cross-correlation TDOA approach, and two that difference the signals' time-of-arrival at each receiver. Each algorithm was evaluated for consistency and accuracy in each environment. Multipath mitigation was demonstrated using a locally fabricated antenna. Collected NTSC broadcast signal samples reveal TDOA measurement errors ranging from 1 to 200 meters, with typical errors between 10 and 40 meters. Multipath was shown to be the dominant error source. However, errors due to the particular hardware configuration used in this research were also significant. Simple multipath mitigation techniques were able to reduce these errors, and analyses of the received waveforms provide the foundation for developing additional active multipath mitigation techniques. Simulations using eight television station locations near Dayton, Ohio reveal 40 meter position accuracy with the typical range errors found in this research. Extreme measurement errors from high multipath areas reduced this accuracy to 100 meters.
DTIC Accession Number
Eggert, Ryan J., "Evaluating the Navigation Potential of the National Television System Committee Broadcast Signal" (2004). Theses and Dissertations. 4039.