; SHADO ;--------------------------------------------------------------- ;! Calculate the shadowing of antennas at the array ;# TASK ANALYSIS UV ;----------------------------------------------------------------------- ;; Copyright (C) 2003-2004, 2008 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- SHADO LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC SHADO creates print out of the sensitivity affected by shadowing INFILE Antenna location file name in the UVCON format OUTTEXT Output file name. The file is at the LATEX or TEXT format under control of APARM(9) If number of hour angles (APARM(5)) > 11 then the OUTTEXT is not created. APARM Control information: 1: Min source declin., deg 0 => -30 2: Number of declinations 0 => 12 3: Step at declination, deg 0 => 10 4: Min hour angle, hours The hour angles are for the given array center 0 => -4 5: Number of hour angles 0 => 9 see help/explain 6: Step at hour angle, hours 0 => 1 7: Min antenna elevation, deg 8: Max blockage allowed in fraction of the area 9: Format of the OUTTEXT 0 => LATEX 1 => TEXT ---------------------------------------------------------------- SHADO Task: Estimate the sensitivity loosing of an array because of shadowing of the array antennas by each other. The array geometry is given by INFILE. The sensitivity with taking into account the shadowing is determined as the ratio of the number of unshadowed antenna to the total number of antennas. Only antennas with elevation exceeded the given elevation limit are taking into account. The antenna is called shadowed if the blockage exceeds the given limit of blockage. Adverbs: INFILE.......Antenna location file name. See format in EXPLAIN OUTTEXT......Output file name. The file is at the LATEX or TEXT format under control of APARM(9). The OUTTEXT is not created if number of hour angles is .GT. 11. If LATEX then the OUTTEXT is ready to create the output as a table in .ps format using LATEX commands (latex, dvips). You may want to edit the table capture before command 'latex' APARM........Control information: 1: Min source declination, degrees 0 => -30 2: Number of declinations, 0 => 12 3: Step at declination, degrees 0 => 10 Each table rows corresponds to new declination 4: Min hour angle, hours 0 => -4 5: Number of hour angles, 0 => 9 The output file is not created if number of hour angles .GT. 11. The outprint is still appears on display at this case. 6: Step at hour angle, hours. 0 => 1 The hour angles are given for the given array center. 7: Min antenna elevation, deg Only antennas with elevation exceeded APARM(7) are taking into account. 8: Max blockage allowed in fraction of the area. The antenna is called shadowed if the blockage exceeds APARM(8). 9: Format of the OUTTEXT 0 => LATEX 1 => TEXT ---------------------------------------------------------------- SHADO: Task to estimate the sensitivity loosing of an array because of shadowing of the array antennas by each other. PROGRAMMER: L. Kogan, NRAO, Socorro. RELATED PROGRAMS: UVCON SPECIFYING THE ARRAY CONFIGURATION The information defining the array configuration is read by SHADO from an auxiliary input file, supplied by the user. There are files for all the VLA configurations and the VLBA in the AIPSTARS directory. These all have the name *_UVCON. This is a free-format text file. One must list, in the following order: Line 1: The number of antennas. Line 2: The site latitude(geodetic), the site longitude, in degrees, The site height relatively the geoid, in meters. Line 3: A multiplicative conversion factor specifying how the antenna coordinates, listed next by the user, can be converted into units of meters; and a second multiplicative conversion factor specifying how the listed antenna diameters can be converted into units of meters. If the antenna location coordinates are given in nanoseconds, the conversion factor is 0.299. The remaining lines specify the antenna location and parameters, with one line for each antenna. Each line is formatted thus: Col. 1: The coordinate system: All are right-handed. Units are in meters, (but see note for Line 3, above). 0 => Equatorial, with X positive towards Greenwich longitude (and latitude = 0), Y to the 'east', and Z to the North Pole. Units in meters, but see Line 3 description above. Warning: VLBA uses opposite direction for Y axis, so you need to change it if you use it. 1 => Local Horizon, with X positive towards east, Y positive towards north, Z positive to local zenith. Units in meters, but see Line 3 description above. Coordinate origin is at the array center. 2 => Geodetic, with coordinates given by geodetic latitude, longitude (positive towards west), (both in degrees) and elevation above the geoid (in meters). 3 => Array Centered Equatorial. The same as '0' but with X positive to Dec = 0 on local meridian, Y positive to east, and Z positive towards NCP. This option is good for VLA Units in meters, but see Line 3 description above. Col. 2: Antenna Coordinate X, as defined above. Col. 3: Antenna Coordinate Y, as defined above. Col. 4: Antenna Coordinate Z, as defined above. Col. 5: Antenna diameter (meters, but see note for Line 3, above). The coordinate system can be mixed up inside of the INFILE Here is a sample file for a six-element array: 6 30 20 1 1 3 499.8614 -1317.9860 -735.2027 10 1 -801.3750 -124.9699 1182.1318 20 3 -5271.2720 -823.5634 7791.9982 30 3 152.7899 -401.2680 -223.3888 40 3 -6870.8985 -1072.9210 10148.7829 50 3 765.2380 2889.4558 -1108.8724 60 The array center is at latitude 30 degrees and longitude 20 degrees to west. Conversion factors for both antennas positions and diameters equal 1, so the relevant values are given in meters. Position of the second antenna is given in the local RH system with Z as local zenith. All other antennas' positions are given in a local equatorial coordinate system. Diameters of the antennas are 10, 20, 30, 40, 50, and 60 meters. One must supply the name of the input file via the AIPS adverb INFILE. Examples: INFILE='myarea:test.ant' (Unix) where MYAREA is an environment variable set before starting AIPS. For example: %setenv MYAREA /mnt/myarea/sim (in csh) $export MYAREA=/mnt/myarea/sim (in ksh)