With the general availability of extensive computer facilities, complex synthetic aperture array problems can be solved to an arbitrary degree of accuracy. Simple approximate models are useful for rapid first order evaluations, but their real value lies in the physical insight which they provide. For illustrative purposes only, the synthetic aperture is treated as a transmitter, directing an optical beam to a remote target. The synthetic optical aperture concept is illustrated in figure 1. Two or more telescopes are pointed at, and focused on, the same remote target. Each individual elementary telescope produces a small section of a spherical wave which converges on the target. The effectiveness of the synthetic aperture is determined by how complete and how perfect is that converging spherical wave.
"Physical Understanding Of Synthetic Aperture Arrays Via Simple Models", Proc. SPIE 0440, Synthetic Aperture Systems I, (2 March 1984); doi: 10.1117/12.937571; https://doi.org/10.1117/12.937571