Keeping Track of Calibration Tables

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4.2.2 Keeping Track of Calibration Tables

Figure 4.2: Chart of the table flow during calibration. The parameter names for input or output of the tasks are shown on the connectors. Note that from the output solver through the accumulator only a single calibration type (e.g. ’B’, ’G’) can be smoothed, interpolated or accumulated at a time. accum is optional and all calibration files. The final set of cumulative calibration tables of all types (accummulated or as a list of caltables) are then input to applycal as shown in Figure 4.1.

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The calibration tables are the currency that is exchanged between the calibration tasks. The “solver” tasks (gaincal, bandpass, blcal, polcal) take in the MS (which may have a calibration model attached) and previous calibration tables, and will output an “incremental” calibration table (it increments the previous calibration, if any). This table can then be smoothed using smoothcal if desired.

You can optionally accumulate the incremental calibration onto previous calibration tables with accum, which will then output a cumulative calibration table. This task will also interpolate onto a different time scale. See § 4.5.5 for more on accumulation and interpolation.

Figure 4.2 graphs the flow of these tables through the sequence

solve => smooth => accumulate

Note that this sequence applied to separate types of tables (e.g. ’B’, ’G’) although tables of other types can be previous calibration input to the solver.

The final set of cumulative calibration tables is what is applied to the data using applycal. You will have to keep track of which tables are the intermediate incremental tables, and which are cumulative, and which were previous to certain steps so that they can also be previous to later steps until accumulation. This can be a confusing business, and it will help if you adopt a consistent table naming scheme (see Figure 4.2) for an example naming scheme).

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