2.4.1.0 simulator.open

2.4.1 Construct a simulator tool and creating a new MeasurementSet
Description

This is used to construct simulator tools. A simulator tool can either be instantiated from an existing MeasurementSet, predicting and/or corrupting data on the given coordinates, or it can be used to create a fundamentally new MeasurementSet from descriptions of the array configuration and the observational parameters. This is useful for making a simulator tool which will make a MeasurementSet from scratch. In order to do this, you must also run setconfig, setfield, setspwindow, setfeed, and settimes. Creating the actual MS is performed by observe. Data can be predict-ed and then corrupted-ed. In this example, we read in the antenna coordinates from an ASCII file:


Inputs
ms	MeasurementSet to be created
	allowed:	string
	Default:

  tabname = ’VLAC.LOCAL.TAB’
  asciifile = ’VLAC.LOCAL.STN’
  mytab=table.create()
  mytab.fromascii(tabname, asciifile);
  xx=[]; yy:=[]; zz:=[]; diam:=[];
  xx = mytab.getcol(’X’);
  yy = mytab.getcol(’Y’);
  zz = mytab.getcol(’Z’);
  diam = mytab.getcol(’DIAM’);
#
  sm.open(’NEW1.ms’)
# do configuration
  posvla = me.observatory(’vla’);  #  me.observatory(’ALMA’) also works!
  sm.setconfig(telescopename=’VLA’, x=xx, y=yy, z=zz, dishdiameter=diam,
        mount=’alt-az’, antname=’VLA’,
                coordsystem=’local’, referencelocation=posvla);

# Initialize the spectral windows
  sm.setspwindow(spwname=’CBand’, freq=’5GHz’,
    deltafreq=’50MHz’,
    freqresolution=’50MHz’,
    nchannels=1,
    stokes=’RR RL LR LL’);
  sm.setspwindow(spwname=’LBand’, freq=’1.420GHz’,
    deltafreq=’3.2MHz’,
    freqresolution=’3.2MHz’,
    nchannels=32,
    stokes=’RR LL’);

# Initialize the source and calibrater
  sm.setfield(sourcename=’My cal’,
sourcedirection=[’J2000’,’00h0m0.0’,’+45.0.0.000’],
calcode=’A’);
  sm.setfield(sourcename=’My source’,
sourcedirection=[’J2000’,’01h0m0.0’,’+47.0.0.000’]);

  sm.setlimits(shadowlimit=0.001, elevationlimit=’8.0deg’);
  sm.setauto(autocorrwt=0.0);

  sm.settimes(integrationtime=’10s’, usehourangle=F,
               referencetime=me.epoch(’utc’, ’today’));

  sm.observe(’My cal’, ’LBand’, starttime=’0s’, stoptime=’300s’);
  sm.observe(’My source’, ’LBand’, starttime=’310s’, stoptime=’720s’);
  sm.observe(’My cal’, ’CBand’, starttime=’720s’, stoptime=’1020s’);
  sm.observe(’My source’, ’CBand’, starttime=’1030s’, stoptime=’1500s’);

  sm.setdata(spwid=1, fieldid=1);
  sm.predict(imagename=’M31.MOD’);
  sm.setdata(spwid=2, fieldid=2);
  sm.predict(imagename=’BigLBand.MOD’);
  sm.close();

simulator.open - Function