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Characterization of On-Orbit GPS Transmit Antenna Patterns for Space UsersThe GPS Antenna Characterization Experiment (GPS ACE) has made extensive observations of GPS L1 signals received at geosynchronous (GEO) altitude, with the objective of developing comprehensive models of the signal levels and signal performance in the GPS transmit antenna side lobes. The experiment was originally motivated by the fact that data on the characteristics and performance of the GPS signals available in GEO and other high Earth orbits was limited. The lack of knowledge of the power and accuracy of the side lobe signals on-orbit added risk to missions seeking to employ the side lobes to meet navigation requirements or improve performance. The GPS ACE Project lled that knowledge gap through a collaboration between The Aerospace Corporation and NASA Goddard Space Fight Center to collect and analyze observations from GPS side lobe transmissions to a satellite at GEO using a highly-sensitive GPS receiver installed at the ground station. The GPS ACE architecture has been in place collecting observations of the GPS constellation with extreme sensitivity for several years. This sensitivity combined with around-the-clock, all-in-view processing enabled full azimuthal coverage of the GPS transmit gain patterns over time to angles beyond 90 degrees off-boresight. Results discussed in this paper include the reconstructed transmit gain patterns, with comparisons to available pre-fight gain measurements from the GPS vehicle contractors. For GPS blocks with extensive ground measurements, the GPS ACE results show remarkable agreement with ground based measurements. For blocks without extensive ground measurements, the GPS ACE results provide the only existing assessments of the full transmit gain patterns. The paper also includes results of pseudorange deviation analysis to assess systematic errors associated with GPS side lobe signals.
Document ID
20180006897
Document Type
Conference Paper
Authors
Donaldson, Jennifer E. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Parker, Joel J. K. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Moreau, Michael C. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Highsmith, Dolan E. (Aerospace Corp. Greenbelt, MD, United States)
Martzen, Phillip (Aerospace Corp. Greenbelt, MD, United States)
Date Acquired
October 25, 2018
Publication Date
September 24, 2018
Subject Category
Astronautics (General)
Report/Patent Number
GSFC-E-DAA-TN60821
Meeting Information
ION GNSS+ 2018(Miami, FL)
Funding Number(s)
CONTRACT_GRANT: SAA5-14-2-N16999
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.
Keywords
space
service
volume

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