28nov11:Rediscovering the Galaxy with atm az swings.

• Dual beam mode with zach=0 and zaDome=15 deg.
• Az rotation was  .39 deg/sec
• The dbraw routine ran clp,mrac,power, and topsd.
  
• Each ran for 10 to 20 seconds and then stepped to the next program.

• Dynamic spectra were made of the power profile data.
• Data from 14:30 to 16:42 AST on 28nov11 were used.
  
• The power was computed for each of the 2400 power profile heights of each 10 millisec ipp.
  
• The barker code was not decoded.
• The heights were averaged and then decimated by 3 to give 800 heights (2*3=6usecs spacing)
• 100 ipps were averaged to give 1 second time resolution.
• The images were scaled to N sigma using a robust algorithm for computing sigma (N=3.5 for ch, 4.5 for dome)

• The horizontal scale is hours (AST) the vertical is range (km)
• The large strip at 16.5 hours is when the system was switched from sky to load.
  
• Some atmospheric signals:
• 110 Km = this is probably the e-region. Since the barker code is not decoded, any lines get smeared out to 13*2 26 usec + the average by 3 heights.
• 250 Km.. the F-region
• The vertical stripes duration is the 10 seconds of each profile.
• I've plotted each 10 second power profile dataset adjacent to each other rather than leaving blank space where mracf, clp, and tpsd ran.
• Carriage house data:
• There is an increase in power along all heights around 15.48 hours
• Dome data.
• There are multiple vertical stripes of increased power regularly spaced.
• The bright strips are spaced by about 16 minutes.
• The time for 1 rotation istime spacing is 15.1 minutes + the turn around time overhead (probably 20 secs). This is pretty close to the spacing of the peaks. The galaxy also moves a bit during this time.
  

• The data from the dynamic spectra were averaged over the 2400 heights and 10 seconds of each power profile giving  2 power samples every 10 secs of a power profile run (1 for the dome and one for the ch).
• Page 1: positions
  
• TOP: Dome azimuth vs hour of day for the power profiles.
• Bottom: right ascension and declination for each of the power samples.
• Black is the ch.
• At 0 degs za it looks at 18.3 degrees declination
• Red is the dome
• At 15 deg za, the dome swings between 3 and 33 deg declination (18-15, 18+15 where 18 is the  declination of AO).
• Page 2: power vs positions
• Top: Total power vs hour of day (AST).
• black is ch, red is dome.
• The dome has many peaks (which showed as the vertical stripes i the dynamic spectra).
• The ch has one main peak around 15.5 hours AST.
• Middle: power vs right ascension.
• The ch peaks at 19.5 hours RA. This is probably the galaxy transiting at declination = 18.3 deg.
• The peak is about 1.5 * Tsys.
  
• The dome peaks earlier at 19.0 hours. It's peak more than doubles Tsys.
  
• Since the dome is swinging +/-15 degs declination it probably crosses a portion of the galaxy that is stronger than declination = 18.3.
• When the dome crosses 19.5 hours RA, it's level is comparable with the ch value (although the baselines vary by about 10%).
  
• Bottom: Total power vs azimuth.
• Page 3: power vs Azimuth for ch (last 3 swings)
• Previously it was noted that some noise was coming from the transmitter building (az = -20deg).
• With the ch at za=0 and the domeza=15, the dome should shield the ch from this noise every time the dome passed between the ch and transmitter building (az=-20).
• Looking at the last last 3 azswings for the ch, there is not obvious dip in the total power near -40 to 0 deg azimuth. This may just be that the sampling rate is to low, or that 10 second averaging has washed out the narrow noise spikes.

Summary:

• The galaxy was seen in the dome and ch during the azimuth swings.
• The ch has a single peak since it stays at za =0 (dec=18.3)
• The dome sees many peaks (in time) since it is continually swinging through the galaxy while the galaxy transits.
• The galaxy increases the ch Tsys by 50%. The galaxy double the tsys on the dome.
  

30aug11: removing clutter from clp echotek images.

• the clp clutter.
• various baseline removal techniques.
• the difference between removing the baseline at the peak (narrow plasma line) versus removing the baseline where the vertical gradient is smallest (giving the most smearing within 1 range gate).

Processing:

• The datafile used was: daeron/t2634_30aug11/t2634_30aug2011_000_004.shs.
• The 10 seconds of data started at 8:10:49 ast.
  
• The fregion was till low, so the vertical gradient was at minimum (causing more altitude smearing).
• The clp data was taken with:
• 2 usec baud, 1 usec spacing between heights.
  
• 5 MHz bandwidth (from the dome). Cfr about 436.5 MHz.
  
• 2400 heights (with 1 usec spacing) were decoded (90 to 450 km range).
  
• decoding used 4096 length fft giving 1.2Khz frequency channel width.
• 1000 ipps or 10 seconds of data were processed for the images.
• 8 threads were used to process the data on aserv21.
• The data was processed on aserv21 from the directory /share/megs/phil/svn/pdev/pdev/clp using the command:
• clp1shs.sc --endtime   --nippaccum=1000 --fftlen=4096 --nthreads=8  --nfiles=1 --odir=/tmp/clp1shs/
   --inpdir=/mnt/daeron/t2634_30aug2011 --inpfilepre=t2634_30aug2011_
  
  

• Page 1: Raw spectra and band pass correction:
  
• Top Raw spectra:
• black: spectra a Fregion peak (210 km)
• green: spectra at minimum height gradient (184 km)
• red: avg spectra (200 heights) 420-449 km. This should not have any atmosphere in it.
• The power goes up at the edges of each spectra. This is aliased power from outside the 5 MHz band
• Bottom: spectra with red bandpass correction divided out:
• the red spectra from the top plot was divided into the black and green spectra to remove the system filter shape.
• This is incorrect for the edges of the spectra because of the aliased power.
• Page 2: data  and various smoothing filters to try  and remove clutter:
  
• The increase in the spectra around freq channel number 2400 is caused by clutter.
  
• Various bandpass filters were computed to be laster used to subtract off the clutter:
• boxcar smoothing of 32 (red),  64 (green) channels, and median filtering with 71 channel length (blue) were computed.
  
• top,2nd: 210 Km fregion peak.
• top: spectra at peak with 3 filtered spectra over plotted. The plasmaline is to the right of the clutter peak.
  
• 2nd. blowup around plasmaline of spectra at peak and  3 filters
• The  plasmaline is about 10 frequency channels wide.
• The colored lines show how much each filter would lower the amplitued of the plasmaline.
• 3rd,4th spectra at 184 km (gradient minimum).
• 3rd spectra with the 3 filtered spectra overplotted. The plasmaline is around channel 1600.
• 4th blowup around the plasmaline with the 3 filters overplotted.
• The plasmaline is about 30 channels wide.
• the filters (especially the 32 channel boxcar) will remove much of the plasmaline.

• at the peak where the plasmaline is narrow, boxcar filters can be used to remove the clutter
• Where the vertical gradient is small, boxcar filters will remove much of the plasmaline.
• using wider boxcar filters will fail at the peak where the clutter has the most curvature.

Dynamic spectra showing various filters:

• You should not see a remnant  of the plasmaline in the filter.
• You should see little clutter in the data - filter
• The plasmaline should be stronger below the peak than above the peak.

Summary:

• Filtering the spectra to remove the clutter does not do a good job at all altitudes:
• At  the minimum gradient in altitude the plasmaline is smeared (because of our height resolution).
  
• This requires a wide filter
• At the peak, a wide filter does not do a good job of removing the clutter.
• The shadow plasmalines are caused by the buad transitions (2 usecs = .5 MHz) beating with the actual plasmaline.

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