p3094: rfi in puppi.. gps

• lband, coherent search, 512 channels over the 800 mhz bw.
• 10 usec dumps.

    I Looked at the first file of the scan (after combining the gpu files)

• puppi_57528_C0531+33_0325_0001.fits
  
• 214.5 seconds of data
• 41 gbytes,
• 720 rows, each row .3 seconds

• Page 1:
  
• top: overplot the 720 .3 second spectra
• The red dashed lines are the gps satellite frequencies
• Bottom:
• plot the GPS L1 power vs time for the file
• i averaged 3.5 Mhz about 1575.2 Mhz
• the oscillations is probably from the scattering of the satellite signal from some of the beams on the platform
• The signal is getting strong as the scan progresses
• Page 2: gps constellation az,za (relative to AO) for 20may16)
• The transit time of each satellite if printed on the right
• The bottom frame, GPS27  transitted at 12:45:15 (ast).
• it got down to a za of about 8 deg.
• Page 3: angular distance GPS27 and source C0531+33
• This shows the angular distance (degrees) between the satellite and the source that was being tracked.
• It started off 4.6 degrees from the beam.
• By the end of the first file.. it was 2.5 degrees away

Summary:

• The rfi reported by the user was probably from the GPS sat svn 27..
  
• I looked at the first 214 seconds (file 1 of the scan)
•  The satellite probably continued to approach the beam in the files that followed.

processing: x101/160520/puppi_frb_rfi.pro

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