a2048: GPS l3 remains on

04apr18


Links to sections

Dynamic spectra  of the 9 scans
gps L3 power vs time
Satellite locations
Summary





    Project a2048  took data on 04apr18 01:37 to 05:13 UTC using alfa and the mock spectrometers. They reported GPS l3 interference for most of the run.

Their setup was:

Dynamic spectra for  the 9 data scans

The table below identifies the different rfi bands
freq
source
1381.05
GPS L3
1349.6,1344.4,1257.6,1252.5
FAA radar
1294.5,1279.5,1243.5,1228.5
Punta salinas radar
1288,1278
galileo satellite E6 band
1268
beidou satellite
1246
glonass?


Total power GPS L3 versus time

    The average power 1381.05 +/- .5 Mhz was computed for each 1 second spectral sample.
The data was normalized  to Tsys when the rfi was off.

the plot shows the GPS L3 frequency power vs time (.ps) (.pdf)

Location of satellites

    The GPS satellites are in 1/2 sidereal orbits (every l1.x hours). (not sure about galileo).
Plots were made of the az,za  (relative to AO) for each satellite of the GPS and galileo constellations. The
pass selected was the closest to the observation times (00:00 01:00 ast 04apr18).
The right side of the plot labels the satellite and the AST date/time for the closest approach of the pass.

GPS constellation      (.ps) (.pdf)
glonass constellation (.ps) (.pdf)

The final plots shows the GPS satellites that were above the horizon during the observation (.ps) (.pdf)

Summary:


processing: x101/180404/gpsrfi .pro




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