Results of Shipboard Relative GPS (SRGPS) Testing for the Pegasus X-47A Unmanned Combat Air Vehicle (UCAV)

P. Sousa, L. Wellons

Abstract:	The U.S. Congress has mandated that unmanned air vehicles will become a significant percentage of the DoD aviation fleet in the coming years. The Defense Advanced Research Projects Agency (DARPA) and the Office of Naval Research (ONR) established the Naval Unmanned Combat Air Vehicle (UCAV-N) effort to demonstrate integration of an airborne unmanned combat system with U.S. Navy aircraft carrier operations. The UCAV-N missions include surveillance, strike, and suppression of enemy air defenses. The UCAV-N effort seeks to identify a design for the UCAV-N Operational System (UOS), to map the Technologies, Processes and System Attributes (TPSAs) which are critical enablers for system success, and finally to design a UCAV-N Demonstration System (UDS) to mature the identified TPSAs. A critical technology for UCAV-N is being developed under the Joint Precision Approach and Landing System (JPALS) program. Navigation of the UCAV-N and its sea-based operational concept are based on the Shipboard Relative GPS (SRGPS) component of JPALS. SRGPS provides three critical functions to facilitate the routine operation of UCAV-N from aircraft carriers: (a) reliable and safe automatic launch and recovery in both normal and adverse weather; (b) operations in the control zone under visual (VFR) and instrument (IFR) flight rules as well as Emissions Control (EMCON) conditions; and (c) ability to "see and avoid" other aircraft. Current shipboard systems have limited coverage, do not fully support EMCON or VFR operations, fall short of the required reliability, and require significant manual effort to operate. Northrop Grumman Corporation went beyond the studies required under the UCAV-N Phase I program and internally funded development of the X-47A Pegasus air vehicle. Among other goals, Pegasus was designed and built to demonstrate aerodynamic flying qualities and navigation and control systems suitable for aircraft carrier operations. This early demonstration of UCAV-N carrier suitability represents a dramatic acceleration of the UCAV-N concept. The Naval Air Systems Command (NAVAIR) similarly accelerated the maturation of the JPALS concept by building an SRGPS prototype, integrating it with an F/A-18, and successfully conducting automatic landings aboard the USS Theodore Roosevelt (CVN-71) in April 2001. With this concept demonstrated, the SRGPS prototype was integrated with the Pegasus air vehicle and Mission Control System (MCS). Once integration and buildup testing was completed, the Pegasus equipped with SRGPS was flight tested at the NAVAIR facility at China Lake, CA. Specific demonstration objectives included: ·•Low Speed Aerodynamic Handling Qualities·•Compatibility with the SRGPS Carrier Landing System·•Simulated Arrested Landings·•Air Vehicle Management System Applicability to Future Unmanned Vehicles. This paper focuses on the results of the first flight of the X-47A Pegasus at China Lake, CA. Landing performance of the air vehicle as well as SRGPS navigation system performance results are presented. The first flight of a U.S. Naval Unmanned Combat Air Vehicle demonstrator using SRGPS to meet the demonstration objectives represents a significant accomplishment for unmanned aviation.
Published in:	Proceedings of the 59th Annual Meeting of The Institute of Navigation and CIGTF 22nd Guidance Test Symposium (2003) June 23 - 25, 2003 Hyatt Regency Hotel Albuquerque, NM
Pages:	291 - 300
Cite this article:	Sousa, P., Wellons, L., "Results of Shipboard Relative GPS (SRGPS) Testing for the Pegasus X-47A Unmanned Combat Air Vehicle (UCAV)," Proceedings of the 59th Annual Meeting of The Institute of Navigation and CIGTF 22nd Guidance Test Symposium (2003), Albuquerque, NM, June 2003, pp. 291-300.
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