1. A method for identifying persistent scatterers in digital Synthetic Aperture Radar (SAR) images of an area of Earth's surface each taken at a respective time, the method comprising: processing, via a processing device, the digital Synthetic Aperture Radar (SAR) images to produce digital generalized differential interferograms; and analyzing, via the processing device, properties of pairs of pixels in the digital generalized differential interferograms to identify individual pixels imaging persistent scatterers, wherein analyzing, via the processing device, properties of pairs of pixels in the digital generalized differential interferograms includes (i) determining, via the processing device, temporal-coherence-related values (γ a ) for the pairs of pixels, and (ii) identifying, via the processing device, said individual pixels based on the determined temporal-coherence-related values (γ a ).