The WAAS/L5 Signal for Robust Time Transfer: Adaptive Beamsteering Antennas for Satellite Time Synchronization

D. S. De Lorenzo, S.C. Lo, J. Seo, Y-H. Chen, P.K. Enge

Abstract:	Geostationary satellites of the Wide Area Augmentation System (WAAS) offer a novel, robust, and cost-effective means of synchronizing time at widely-separated ground facilities, to levels of ~50ns, without the need for dedicated long-distance wired communication networks. However, reliance on satellite-based signals for time synchronization in high-reliability applications is problematic without explicit hardening against radio frequency interference (RFI). The primary innovations to be discussed in this paper are: (1) adaptive electronicallysteered multi-element antenna arrays and signal processing strategies for RFI mitigation, (2) live signal, synthetic interference, and hardware-in-the-loop testing of jammer cancellation algorithms, and (3) preparations for over-the-air interference tests which will probe the effects of front-end saturation on digital beamsteering performance. We describe a hardware system assembled from readily-available commercial building blocks (data acquisition system, antennas, etc.), and a critical goal of this research is to realize significant GPS anti-jam performance in an open-architecture (or non-defenserelated) platform. Therefore, the central innovations in this research enable adaptive electronic beamsteering with high-dynamic-range signals (14-bit I/Q digitization), employing commercial off-the-shelf (COTS) hardware and computer systems, and targeted for a civilian highreliability, high-volume (many hundreds of deployed systems) GPS timing application.
Published in:	Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010) September 21 - 24, 2010 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	2106 - 2116
Cite this article:	De Lorenzo, D. S., Lo, S.C., Seo, J., Chen, Y-H., Enge, P.K., "The WAAS/L5 Signal for Robust Time Transfer: Adaptive Beamsteering Antennas for Satellite Time Synchronization," Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010), Portland, OR, September 2010, pp. 2106-2116.
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