Sampling aspects of interferometry

Interferometric methods can be used to create virtual sources at locations of physical receivers. Then the effect of changing surface conditions is minimized and these will not play a role in the antenna surface impedance changes. Replacing physical source locations by virtual sources at physical receiver locations is feasible using cross-correlation and multi-dimensional deconvolution techniques. Interferometry requires a large receiver span width. It is therefore desired to minimize the amount of receivers in this receiver array. This can be done by interpolating between receiver-positions on a non-linear grid. Within the region defined by Snell´s laws critical angle, the receivers collect data to `look´ to the reflections of the virtual source. While the receivers outside this region collect data so that the before mentioned receivers can `see´ more clearly.