A major part of the design effort will be to determine what is done in common among the various instruments and what is done differently. It may be possible to increase the commonality by negotiations among representatives of the various instruments. This process cannot even be started without a coherent and detailed descriptions of the requirements of the different instruments. Many of these technical details were discussed in Green Bank but were not included into the resulting document. If auxiliary measurements, such as system temperature or instrumental delay, are needed in the calibration process this should also be specified.
Calibration is probably the area with the largest instrument to instrument variations.
What is needed for each instrument is the detailed model of the instrumental response and how the parameters are determined and corrections applied. It is not clear to me whether or not calibration normally done by observatory staff such as antenna pointing calibration is within the scope of this project. The range of calibration to be considered needs to be settled fairly soon. For each instrument a description of how the calibrated data is converted to the image domain is necessary. For example, in AIPS VLA teh calibrated correlations are convolved with any one of a number of convolving functions and sampled at a bounded set of regular grid spacings on a single half plane of the uv plane.