setup name=uvgen \ source=$MIRCAT/point.source \ ant=$MIRCAT/bima9_c.ant \ corr=0,1 \ gnoise=0 pnoise=0 systemp=0,0,0 tpower=0,0 jyperk=150
The presence of this setup will cause mint to automatically invoke the standard MIRIAD task uvgen and create model visibility files. A few of the UVGEN specific keywords must be added to the uvgen setup, although most of them are computed by checker's version of MINT (see table below). Also note that those keywords which are filenames must be with their full pathname, since the observe script is not necessarely run where you expect it. Another problem which needs to be looked into is the random number generator used in MIRIAD: it causes uvgen to generate the same series of random numbers each time.
Also note that the presence of the uvgen setup has no meaning during observations, and does not have to be commented out.
required: source a file with gaussian source(s), see $MIRCAT/*source ant a file with antenna postitions, see $MIRCAT/*ant corr tricky (TODO: INHERIT?) freq ignored (TODO: INHERIT) itime optional: (with some random number generator limitations) gnoise Antenna based gain noise, given as a percentage. This gives the multiplicative gain variations, specified by the rms amplitude to be added to the gain of each antenna at each sample interval. The gain error stays constant over the period given by the ``cycle(1)'' parameter (see above). Thus ``cycle(1)'' can be varied to give different atmosphere/instrument stabilities. Note that the default of the ``cycle'' parameter means that the gain changes every integration. A gain error can also be used to mimic random pointing errors provided the source is a point source. The default is 0 (i.e. no gain error). pnoise Antenna based phase noise, in degrees. This gives the phase noise, specified by the rms phase noise to be added to each antenna. Up to 4 values can be given to compute the phase noise pnoise(1) + pnoise(2)*(baseline)**pnoise(3)*sinel**pnoise(4) where ``baseline'' is the baseline length in km. Typical values for pnoise(2) are 1mm rms pathlength (e.g. 2 radians at 100 GHz), For Kolmogorov turbulence pnoise(3)=5/6 for baseline < 100m and 0.33 for baseline > 100m (outer scale of turbulence). pnoise(4)=-0.5 for a thick turbulent screen, and -1 for a thin layer. See also the ``gnoise'' parameter. Default is 0,0,0,0 (i.e. no phase error). systemp System temperature used to compute additive random noise and total power. One or 3 values can be given; either the average single sideband systemp including the atmosphere (TELEPAR gives typical values), or the double sideband receiver temperature, sky temperature, and zenith opacity, when systemp is computed as: systemp = 2.*(Trx + Tsky*(1-exp(-tau/sinel)))*exp(tau/sinel) where systemp, Trx and Tsky are in Kelvin. Typical values for Hat Ck Trx, Tsky, and tau are 75,290,0.15. (OBSTAU gives values for tau). systemp is used to generate random Gaussian noise to add to each data point. Default is 0,0,0 (i.e. no additive noise). tpower Two values can be given to represent the total power variations due to receiver instability (Trms), and atmospheric noise (Tatm). tpower = Trms * systemp + Tatm * pnoise The receiver instablity is modeled as multiplicative Gaussian noise. The atmospheric noise is modeled to be correlated with the antenna phase noise. Typical values at 3 millimeter wavelength are Trms=10-3 and Tatm=0.2 K/radian (280 degrees/K). Default is tpower=0,0 jyperk The system sensitivity, in Jy/K. Its value is given by 2*k/(eta * A) where k is Boltzmans constant (1.38e3 Jy m**2 / K), A is the physical area of each antenna (pi/4 * D**2), and eta is an efficiency. For the ATCA, D is 22 meters, and eta is composed of a correlator efficiency (0.88) and an antenna efficiency (0.65 at 6 cm). The overall result is jyperk=12.7. The default jyperk=150, a typical value for the Hat Creek 6.1 m antennas. options (Not of any use for BIMA data yet, mostly for ATNF simulations) internally derived: out DO NOT USE (vis=) time DO NOT USE (computed) radec DO NOT USE harange DO NOT USE elev DO NOT USE stokes ???(not used for now) polar ???(not used for now) lat DO NOT USE cycle DO NOT USE center