Precision Navigation for UAS Critical Operations

Alison K. Brown, Dien Nguyen and Paige Felker, Glenn Colby and Frank Allen

Abstract:	The Navy Unmanned Combat Air System (N-UCAS) is a carrier-based, autonomous combat air vehicle designed to conduct long-endurance strike and ISR operational missions. Due to its very nature, the N-UCAS requires the ability to perform precision navigation in a variety of roles. The current precision approach to support Autonomous Aerial Refueling (AAR) relies on a Precision GPS (PGPS) technique utilizing relative kinematic GPS positioning, coupled to an inertial navigation solution. This method depends on the tanker and the Unmanned Aerial System (UAS) tracking common GPS satellites, and then using relative pseudorange and carrier-phase differences to resolve the relative carrier cycle ambiguities between the aircraft’s observations and thus determine their precise relative positioning to update the INS solution. Under contract to the Navy, NAVSYS is developing an alternative PGPS architecture, termed Precision RELNAV (P-RELNAV) where the tanker and the N-UCAS are able to independently navigate to a high degree of precision without requiring carrier cycle ambiguity resolution using Precision GPS Ephemeris (PGE) updates to a tightly coupled GPS/inertial solution onboard each aircraft. In this paper, we present test results that show how the PGE-enhanced navigation solution rivals that of conventional relative kinematic techniques while providing a more robust positioning solution that reduces message traffic between aircraft and does not require a long filtering time to obtain carrier cycle ambiguity resolution.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	1870 - 1876
Cite this article:	Brown, Alison K., Nguyen, Dien, Felker, Paige, Colby, Glenn, Allen, Frank, "Precision Navigation for UAS Critical Operations," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 1870-1876.
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