GPS Antenna Characterization Experiment (GPS ACE) 
Reconstructed GPS L1 Antenna Patterns

README Generated on 09-Oct-2018
Source: https://esc/gsfc.nasa.gov/navigation

Antenna Pattern Data Column Definitions:
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GPS Off-Nadir (deg) 

This angle is defined as the off-boresight or off-nadir angle which points along
the +z axis of the spacecraft body frame. An angle of 0 degrees indicates
boresight of the antenna.

GPS Azimuth (deg) 

This angle is defined as the azimuth angle referenced from the +x axis of the
spacecraft body frame with a positive rotation about the +z axis.  An azimuth
angle of 0 degrees indicates a point on the +x axis and and angle of 90 degrees
indicates a point on the +y spacecraft body frame axis. 

Gain (dB)

The reconstructed GPS antenna gain in dB.

Std Dev of Gain

The standard deviation of the data points used to create the average gain for
each off-nadr/azimuth pair. This is an indicator of variation in the data set,
however, it is not an absolute measurement of the accuracy of the reconstructed
gain value. A 'NaN' value in this column indicates that no data was available
and therefore the corresponding value in the gain column is an interpolated
value.

SVN to Block Mappings
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Block IIA SVNs:
23,26,34,38,40

Block IIR SVNs:
41,43,44,45,46,51,54,56

Block IIR-M SVNs:
47,48,50,52,53,55,57,58,59,60,61

Block IIF SVNs:
62,63,64,65,66,67,68,69,70,71,72,73

Normalization Constants Description
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The normalization constants are the mean gain offset between the GPS ACE
reconstructed antenna patterns (before normalization) and available ground
measured gain patterns of the mainlobe. More detailed information on how the
antenna patterns were normailized is provided in the "Characterization of
On-Orbit GPS Transmit Antenna Patterns for Space Users."

GPS Yaw Model Diagrams
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These diagrams provide a visual reference for the GPS spacecraft body frame
definitions by GPS Block. 
