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GPS Space Service Volume: Ensuring Consistent Utility Across GPS Design Builds for Space UsersGPS availability and signal strength originally specified for users on or near surface of Earth with transmitted power levels specified at edge-of-Earth, 14.3 degrees. Prior to the SSV specification, on-orbit performance of GPS varied from block build to block build (IIA, IIRM, IIF) due to antenna gain and beam width variances. Unstable on-orbit performance results in significant risk to space users. Side-lobe signals, although not specified, were expected to significantly boost GPS signal availability for users above the constellation. During GPS III Phase A, NASA noted significant discrepancies in power levels specified in GPS III specification documents, and measured on-orbit performance. To stabilize the signal for high altitude space users, NASA DoD team in 2003-2005 led the creation of new Space Service Volume (SSV) definition and specifications.
Document ID
20150011650
Acquisition Source
Goddard Space Flight Center
Document Type
Presentation
Authors
Bauer, Frank H.
(SGT, Inc. Greenbelt, MD, United States)
Parker, Joel Jefferson Konkl
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Valdez, Jennifer Ellen
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
June 26, 2015
Publication Date
May 27, 2015
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking
Report/Patent Number
GSFC-E-DAA-TN23947
Meeting Information
Meeting: National Space-Based Positioning, Navigation, and Timing Advisory Board Meeting
Location: Annapolis, MD
Country: United States
Start Date: June 11, 2015
End Date: June 12, 2015
Sponsors: NASA Headquarters
Funding Number(s)
CONTRACT_GRANT: NNG11HP14C
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Volume
Design
GPS
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