Design of Second and Third Order PLLs with Adaptive Bandwidth in Real Time

S. Ugazio, M. Fantino, L. Lo Presti

Abstract:	This paper proposes an algorithm which adapts the Equivalent Noise bandwidth (ENB) of a Digital Phase Lock Loop (DPLL) in real time, with the objective to implement it within a fully software receiver. The algorithm is tailored for Global Navigation satellite System (GNSS) receivers, and can be easily implemented in a fully software platform. The algorithm aim is to reduce the dynamics stress error and the tracking jitter which affect the carrier phase estimate as much as possible. As the dynamic stress error is inversely proportional to the ENB, while the tracking jitter due to the noise is directly proportional to it, a trade-off is needed. This goal is reached by minimizing a cost function, containing the sum of two contributions depending respectively on the input dynamics and on the input noise. In particular the input signal frequency is considered linear, so the input dynamics is related to the input frequency slope. The minimum of the cost function is found by using some simplifications, necessary to achieve a computational speed suitable for real-time adaptation.
Published in:	Proceedings of the 2011 International Technical Meeting of The Institute of Navigation January 24 - 26, 2011 Catamaran Resort Hotel San Diego, CA
Pages:	1281 - 1292
Cite this article:	Ugazio, S., Fantino, M., Presti, L. Lo, "Design of Second and Third Order PLLs with Adaptive Bandwidth in Real Time," Proceedings of the 2011 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2011, pp. 1281-1292.
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