Wrong Imaging pipeline settings

An error was found in the settings of the phase-only calibration parset of the ASTRON Imaging Pipeline. The error was fixed on the 26th of June 2015.

The settings used applied the default parameters present in the solution tables (parmdb) to the phases, which is zero in the case of the phase. The effect is that no correction is applied to the phase and therefore the phase values in the CORRECTED_DATA column are the same as those in the DATA column. 

To fix the issue we performed the following changes:

-  in the BBS step Solve the mode has been changed from Phase to Complex
-  in the BBS step Correct the Phasors.Enable=F has been enabled to Phasors.Enable=T.

In order to obtain the proper results from your gms phase-only calibration, we advise you to repeat the initial phase-only calibration using the parset reported below.

BBS.Step.Solve.Baselines=

BBS.Step.Solve.Correlations=[]

BBS.Step.Solve.Model.Bandass.Enable=F

BBS.Step.Solve.Model.Beam.ConjugateAF=F

BBS.Step.Solve.Model.Beam.Element.Path=${LOFARROOT}/share

BBS.Step.Solve.Model.Beam.Enable=true

BBS.Step.Solve.Model.Beam.Mode=ARRAY_FACTOR

BBS.Step.Solve.Model.Cache.Enable=T

BBS.Step.Solve.Model.DirectionalGain.Enable=F

BBS.Step.Solve.Model.Flagger.Enable=F

BBS.Step.Solve.Model.Flagger.Threshold=0

BBS.Step.Solve.Model.Gain.Enable=T

BBS.Step.Solve.Model.Ionosphere.Degree=0

BBS.Step.Solve.Model.Ionosphere.Enable=F

BBS.Step.Solve.Model.Ionosphere.Type=

BBS.Step.Solve.Model.Phasors.Enable=T

BBS.Step.Solve.Model.Sources=[]

BBS.Step.Solve.Operation=SOLVE

BBS.Step.Solve.Output.Column=

BBS.Step.Solve.Output.WriteCovariance=F

BBS.Step.Solve.Output.WriteFlags=F

BBS.Step.Solve.Solve.Algorithm=L2

BBS.Step.Solve.Solve.CalibrationGroups=[]

BBS.Step.Solve.Solve.CellChunkSize=10

BBS.Step.Solve.Solve.CellSize.Freq=0

BBS.Step.Solve.Solve.CellSize.Time=1

BBS.Step.Solve.Solve.EpsilonL1=[1e-4,1e-5,1e-6]

BBS.Step.Solve.Solve.ExclParms=[]

BBS.Step.Solve.Solve.Log.Level=NONE

BBS.Step.Solve.Solve.Log.Name=solver_log

BBS.Step.Solve.Solve.Mode=COMPLEX

BBS.Step.Solve.Solve.Options.BalancedEqs=F

BBS.Step.Solve.Solve.Options.ColFactor=1e-9

BBS.Step.Solve.Solve.Options.EpsDerivative=1e-9

BBS.Step.Solve.Solve.Options.EpsValue=1e-9

BBS.Step.Solve.Solve.Options.LMFactor=1.0

BBS.Step.Solve.Solve.Options.MaxIter=100

BBS.Step.Solve.Solve.Options.UseSVD=T

BBS.Step.Solve.Solve.OutlierRejection.Enable=F

BBS.Step.Solve.Solve.OutlierRejection.Threshold=[7.0,5.0,4.0,3.5,3.0,2.8,2.6,2.4,2.2,2.5]

BBS.Step.Solve.Solve.Parms=["Gain:0:0:Phase:*","Gain:1:1:Phase:*"]

BBS.Step.Solve.Solve.PhaseShift.Direction=[]

BBS.Step.Solve.Solve.PhaseShift.Enable=F

BBS.Step.Solve.Solve.PropagateSolutions=F

BBS.Step.Solve.Solve.Resample.CellSize.Freq=0

BBS.Step.Solve.Solve.Resample.CellSize.Time=0

BBS.Step.Solve.Solve.Resample.DensityThreshold=1.0

BBS.Step.Solve.Solve.Resample.Enable=F

BBS.Step.Solve.Solve.UVRange=[]

BBS.Step.Solve.Model.TEC.Enable =F

BBS.Step.Solve.Model.Beam.UseChannelFreq=T

BBS.Step.Correct.Baselines=

BBS.Step.Correct.Correlations=[]

BBS.Step.Correct.Model.Bandpass.Enable=F

BBS.Step.Correct.Model.Beam.ConjugateAF=F

BBS.Step.Correct.Model.Beam.Element.Path=${LOFARROOT}/share

BBS.Step.Correct.Model.Beam.Enable=true

BBS.Step.Correct.Model.Beam.Mode=ARRAY_FACTOR

BBS.Step.Correct.Model.Cache.Enable=true

BBS.Step.Correct.Model.DirectionalGain.Enable=F

BBS.Step.Correct.Model.Flagger.Enable=F

BBS.Step.Correct.Model.Flagger.Threshold=0

BBS.Step.Correct.Model.Gain.Enable=T

BBS.Step.Correct.Model.Ionosphere.Degree=0

BBS.Step.Correct.Model.Ionosphere.Enable=F

BBS.Step.Correct.Model.Ionosphere.Type=

BBS.Step.Correct.Model.Phasors.Enable=T

BBS.Step.Correct.Model.Sources=[]

BBS.Step.Correct.Operation=CORRECT

BBS.Step.Correct.Output.Column=CORRECTED_DATA

BBS.Step.Correct.Output.WriteCovariance=T

BBS.Step.Correct.Output.WriteFlags=F

BBS.Step.Correct.Model.TEC.Enable =F

BBS.Step.Correct.Model.Beam.UseChannelFreq=T

BBS.Step.nrOfDefaultBBSStep=2

BBS.Strategy.Baselines=*&

BBS.Strategy.ChunkSize=100

BBS.Strategy.Correlations=[]

BBS.Strategy.InputColumn=DATA

BBS.Strategy.Steps=[Solve, Correct]

BBS.Strategy.TimeRange=[]

BBS.Strategy.UseSolver=F

Design: Kuenst.    Development: Dripl.    © 2021 ASTRON