An imaging system includes a platform having mounted thereon a coded-aperture imaging device and positioned to receive radiation over a baseline, and a computer configured to acquire a plurality of far-field datasets over the baseline, the plurality of far-field datasets comprising data received via the coded-aperture imaging device, form a first image from the plurality of far-field datasets, and form a second image if the first image indicates presence of a source, the second image formed from the plurality of far-field datasets using an estimated source location from the first image and thereby having a higher contrast than the first image.