Multi Constellation and BOC-Signal Problems with Group Delay

P.G. Mattos

Abstract:	GNSS signals from different constellations such as GPS/GLONASS are on different frequencies passing down the RF chain of the receiver. Similarly, BOC signals have an upper and a lower sideband separate by some MHz. In both cases, group delay variation with frequency, as found in SAW filters, means the signals are not equally delayed. The measurements documented by the manufacturers refer to the carrier wave itself, but neglect the effect on the modulation or spreading codes. Slope in the group delay response has a vastly magnified effect on the modulation, while non-linearity, or curvature, has complex effects on the correlation response as reported in this paper. Modelling the effect of delay on the signal confirms these theories. Modelling the passage of the signal through the model SAW filter however shows no such effect, indicating that the signal travels at the carrier frequency, not at the sidelobe frequency as suggested by the spectrum analyser.
Published in:	Proceedings of the 2012 International Technical Meeting of The Institute of Navigation January 30 - 1, 2012 Marriott Newport Beach Hotel & Spa Newport Beach, CA
Pages:	1875 - 1909
Cite this article:	Mattos, P.G., "Multi Constellation and BOC-Signal Problems with Group Delay," Proceedings of the 2012 International Technical Meeting of The Institute of Navigation, Newport Beach, CA, January 2012, pp. 1875-1909.
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