Galileo navigation satellites
17may12 galfacts sees the galileo satellites
The galileo satellites are the European global
navigation satellite system
There are currently (may2012) 4 satellites in orbit:
specifications. F0=10.23MHz,14hour orbit.
|carrier:1176.45. Also gpsL5
|covers E5a and E5b.
|1278.75 center. Commerical
service . coded
|shared with gps L1
Fo/10 (B&C chan)
17may12 galfacts sees the galileo
On 17may12 project a2130 (galfacts) received
interference from the galileo satellite galileo-pfm (they saw it
on more than one night)
- 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
- 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
- The red color galileo-pfm reached it's lowest za at 04:18:00
- This satellite rose in the north and passed almost overhead
then setting in the south.
spectra using stokes I showed the satellite as it went overhead
The plots show the spectra and
angular separation (.ps) (.pdf)
- The spectra have been averaged to .3 seconds
- I used the first 700 spectra to compute the bandpass
- 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
- bottom: Same plot on a db scale.
- The side lobes 10 MHz away are about 4 to 6db down from
- 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.
- 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.