Crowded Streets of Spectrum - is GPS Being Walked all Over?

Greg Gerten

Abstract:	The RF spectrum has increasingly become more crowded due to the nature that there only exists so many frequencies and new devices and needs are continually being developed. The radio spectrum, seen in Figure 1, shows just how tight and many slots exist today. Radar, communication, and radio navigation systems all have to share and in some cases overlap each others spectrum. Systems that may cause problems to GPS uplinks, cross-links or downlinks include emissions and spurs from radar systems, communication systems, other navigation systems, and other high power RF systems (weather radars, television, and radio transmitters). While there are standards set up by the International Telecommunications Union (ITU), these are constantly being reevaluated and “bartered” by competing systems and countries to squeeze in more systems in tighter allocations. In this paper, I will investigate the spectrums “bottle-necks” and analyze the effects of spectrum overlap has on GPS. These effects will be analyzed at the engineering level (interference power into the receiver) analyzing the measured power spectral densities (PSD) of several systems and then summarized at a higher level to determine what the impact is of RF overlap on GPS performance.
Published in:	Proceedings of the 63rd Annual Meeting of The Institute of Navigation (2007) April 23 - 25, 2007 Royal Sonesta Hotel Cambridge, MA
Pages:	198 - 203
Cite this article:	Gerten, Greg, "Crowded Streets of Spectrum - is GPS Being Walked all Over?," Proceedings of the 63rd Annual Meeting of The Institute of Navigation (2007), Cambridge, MA, April 2007, pp. 198-203.
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