Intro  (top)

    The galileo satellites are the European global navigation satellite system
There are currently (may2012) 4 satellites in orbit:

17may12 galfacts sees the galileo satellites  (top)

    On 17may12 project a2130 (galfacts) received interference from the galileo satellite galileo-pfm (they saw it on more than one night)

A2130 setup:

• They used the alfa receiver with the mock spectrometers.
  
• 7 beams
• full stokes
• 2x 172MHz 4096 channel full stokes bands 
• Band cfr: 1300, 1450 MHz
• spectra sampled once a millisecond
• The dome moves from 2 to 19.6 degrees and back down at .025 deg/sec with the azimuth sitting at the meridian.

How close does galileo get to the AO during may12?

    The plots show the galileo satellite passes over arecibo for 7may12 - 31may12 (.ps) (.pdf):

• Each frame shows the closest passes for galileo at 4:00am local time
• The horizontal axis is the source azimuth of the satellite (As seen from AO). The azimuth for the dome will be 180 deg different when pointing at the same location.
  
• The vertical scale is the zenith angle of the satellite (az seen from AO).
• The labels on the right side of each frame contain:
• SatelliteName    yymmdd hh:mm:ss  when this satellite reaches the minimum za.
• Page 4, 2nd frame is the satellite pass for the a2130 observation on 17may12 (galileo-pfm red)
  
• The red color galileo-pfm reached it's lowest za at 04:18:00 ast.
• This satellite rose in the north and passed almost overhead then setting in the south.

The interference:

    The dynamic spectra using stokes I showed the satellite as it went overhead (.gif)

• The spectra have been averaged to .3 seconds
• I used the first 700 spectra to compute the bandpass correction.
• The total power in 1315-1325 was used to flatten image in time. This got rid of the za dependence of the tys.
• The rfi is centered at 1278.7 MHz and has side lobes that can be seen out beyond 1300 MHz  and below 1260 MHz (although some of them may be instrumental).

• Page 1: the spectrum at the peak:
• Top: linear spectral plot:
• .3 second integration at 04:24:51 ast.
•  The signal gets up to 8.5 Tsys(about 30K) in the 42Khz channels).
• bottom: Same plot on a db scale.
• The side lobes 10 MHz away are about 4 to 6db down from the peak.
• Page 2: total power in 5 MHz about 1278.7 MHz.
• Top: total power vs hour of day (ast)
• Bottom: angular separation (great circle degrees) between satellite and AO beam.
• The satellite got to about 4.5 degrees of the main beam. The peak occurred about 4.8 degrees from the ao beam.

Summary:

• Galileo-pfm was seen in the a2130 data on 17may12.
• it got to about 7.5*Tsys in a 42Khz channel.
• The rfi was centered at 1278.7 MHz.
• It extended above 1300 MHz and down to 1220 MHz
• The satellite came right overhead AO. It came within 4.5 degrees of the galfacts pointing direction.
• The satellite passes seem to repeat every 10 days (at least in the plots i made..) With a 14 hour orbits, they should repeat every 7 days.