Frequency Calibration of A/D Converter in Software GPS Receivers

L. L. Liou, D. M. Lin, J. B. Tsui, J. Schamus, J. T. Morton

Abstract:	This paper presents a software-based method to calibrate Analog-to-digital converter (ADC) sampling frequency in a software GPS receiver. Two front-end systems of a GPS software receiver were used in this study. The sampling frequencies of the ADC were found deviated from the nominal values provided by the manufacturers. Software algorithm was developed to calibrate the sampling frequencies. The algorithm is based on the initial-code-phase velocity and the carrier-phase velocity of the GPS signals at L1 frequency obtained by software receiver measurements. Allan variance analysis of this frequency characterization method is also included in this study.
Published in:	Proceedings of the 37th Annual Precise Time and Time Interval Systems and Applications Meeting August 29 - 31, 2005 Vancouver, Canada
Pages:	652 - 659
Cite this article:	Liou, L. L., Lin, D. M., Tsui, J. B., Schamus, J., Morton, J. T., "Frequency Calibration of A/D Converter in Software GPS Receivers," Proceedings of the 37th Annual Precise Time and Time Interval Systems and Applications Meeting, Vancouver, Canada, August 2005, pp. 652-659.
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