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Testing the Preliminary X-33 Navigation SystemThe X-33 Reusable Launch Vehicle (RLV) must meet the demanding requirements of landing autonomously on a narrow landing strip following a flight that reaches an altitude of up to 200,000 feet and a speed in excess of Mach 9 with significant in-flight energy bleed-off maneuvers. To execute this flight regimen a highly reliable avionics system has been designed that includes three LN-100G Inertial Navigation System/Global Positioning System (INS/GPS) units as the primary navigation system for the X-33. NASA's Marshall Space Flight Center (MSFC) tested an INS/GPS system in real-time simulations to determine the ability of this navigation suite to meet the in flight and autonomous landing requirements of the X-33 RLV. A total of sixty-one open loop tests were performed to characterize the navigation accuracy of the LN-100G. Twenty-seven closed-loop tests were also performed to evaluate the performance of the X-33 Guidance, Navigation and Control (GN&C) algorithms with the real navigation hardware. These closed-loop tests were also designed to expose any integration or operational issues with the real-time X-33 vehicle simulation. Dynamic road tests of the INS/GPS were conducted by Litton to assess the performance of differential and nondifferential INS/GPS hybrid navigation solutions. The results of the simulations and road testing demonstrate that this novel solution is capable of meeting the demanding requirements of take-off, in-flight navigation, and autonomous landing of the X-33 RLV. This paper describes the test environment developed to stimulate the LN-100G and discusses the results of this test effort. This paper also presents recommendations for a navigation system suitable to an operational RLV system.
Document ID
20010019998
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Lomas, James J.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Mitchell, Daniel W.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Freestone, Todd M.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Lee, Charles
(Litton Systems, Inc. Woodland Hills, CA United States)
Lessman, Craig
(Litton Systems, Inc. Woodland Hills, CA United States)
Foster, Lee D.
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Aircraft Communications And Navigation
Meeting Information
Meeting: Guidance and Control
Location: Breckenridge, CO
Country: United States
Start Date: January 31, 2001
End Date: February 4, 2001
Sponsors: American Astronautical Society
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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