Satellite arcing experiment
29sep15
Satellite arcing experiments:
Miscellaneous measurements:
The processing code is in
/share/megs/phil/usr/satarc/
intro
The satellite arcing experiment (s3043,s3099,..)
is looking for arcs from satellite solar panels using AO and the
327,430 and 47 MHz receivers.
Prior to hurricane maria, the gregorian dome (gr) would look at the
satellite (sometimes doing on,off position switching) piping the
data to the mock spectromenter, while the ch receiver (430 or 47)
would look at blank sky, sending it's data to the radar interface.
The ch beam was used to filter out spikes not coming from the
satellite.
After hurricane maris (the ch line feed fell into
the dish), only the gr receiver was used to monitor the satellite
(doing on,off position switching).
150921: fast dump spectra using the 327
receiver.
On 21sep15 i took some fast dump data using
the 327 receiver. The setup was:
- 327 MHz receiver., 53 MHz bw centered at 327 MHz.
- The telescope was sitting at az=288.3394, za=9.12 degrees
- mock spectrometer, spectral line mode
- dump spectra at 19.2 usecs , 256 channels
- dump spectra at 9.6 usecs , 128 channels
- In both cases data was taken for 60 seconds.
Processing the data:
- each record of data contained about 1 second of data.
- for each record compute the rms/mean along each channel for
all of the spectra in the record
- for each rms spectra do a robust fit of : linear polynomial
and 2nd order harmonic.
- Flags any freq channels that were more than 3 sigma from the
fit.
- For each spectra (19.2 or 9.6 usecs) compute the total power
for the spectra throwing out the channels that had fit rms's
greater than 3 sigma.
the plots show the total power vs time
- total power vs time for
19.2 usec data (.ps) (.pdf)
- top: 4 seconds of total power data
- bottom: blowup around 3.117 seconds
- the spikes lasted from 1 to 5 spectra (19.2 to about 100
usecs)
- there were 1101 points > 1.2 times tsys in the 60 sec
dataset
- there were 3145350 points in 60 seconds
- total power vs time for
the 9.6 usec data (.ps) (.pdf)
- top: 4 seconds of data
- bottom: blowup around .930 seconds
- the spike are mainly 1 sample (< 9.6 usecs)
- there were 3986 points > 1.3 times Tsys in 60 seconds
- there were a total of 6275365 samples in 60 seconds.
Summary
- we see very narrow spikes at both 19.2 and 9.6 usecs
integrations
- This data was taken 17:19 ast. Late at night there may
be fewer narrow spikes.
processing: x101/150921/327arc.pro
03mar17 looking at objects in 327
sidelobes
Most geostationary satellites are below our
minimum dec range (0deg).
One idea to look farther south, is to put the object in a sidelobe
of a the receiver.
The plots shows the sidelobe gain loss (relative
to main beam) vs angular separation from main beam (.ps) (.pdf)
- The plots used:
- 14 Amin for the FWHM of the 327 receiver
- (sin(X)/X)^2 for the sidelobe rolloff (the actual sidelobes
may fall off faster).
- To look 2.5 Degrees away from the main beam, the signal will
be 30db down from the main beam.
processing: x101/170303/satArc_sdlb.pro
home_~phil