Evaluating the Correlation Characteristics of Arbitrary AM and FM Radio Signals for the Purpose of Navigation

摘要

The Global Positioning System (GPS) provides position estimates on the Earth at anytime, anywhere and in any weather. However, to provide robust positioning, GPS requires an unobstructed path to satellite signals. As such, GPS performance generally degrades or becomes non-existent in environments such as large urban areas. This research investigates and analyzes the correlation characteristics of arbitrary AM and FM radio signals for the purpose of navigation. Simulations are conducted with different combinations of correlation methods ('fixed' or 'varying'), modulation types (AM or FM), and signal types (song or voice). Out of the eight different variations considered, only two provided promising results for the purpose of navigation. Both the FM voice and FM song signals exhibit distinct autocorrelation peaks (i.e., 5.0 dB peak-to-sidelobe ratios) using the 'fixed' reference correlation method. However, results for both FM signal types revealed limited potential for navigation when using the 'varying' reference correlation method. All the AM signals considered yielded relatively limited potential for navigation using either correlation method.