On the concept of field-to-resolution ratio in aperture synthesis.

The analysis of the imaging properties of an interferometric device essentially depends on the parameteres that govern the Fourier synthesis operation: extension and density of the experimental frequency coverage (resolution, field, robustness), size and nature of the input errors (input data for the study of the error propagation). Among these parameters, the field-to-resolution ratio (FRR) proves to play a key role, in particular, for array configuration optimization: the number of contiguous elements that can be resolved in the synthesized field is bounded by (FRR)2. The robustness of the corresponding reconstruction process is of course involved in the precise definition of this concept. The corresponding analysis is based on a new method of Fourier synthesis (WIPE), in which all these aspects are clearly specified (WIPE is reminiscent of CLEAN, a well-known deconvolution technique in astronomy).