Synthetic Aperture Radar (SAR) is an active remote sensing technique capable of providing high-resolution imagery independent
from daytime and to great extent unimpaired by weather conditions. However, SAR inevitably requires an oblique scene illumination
resulting in undesired occlusion and layover especially in urban areas. As a consequence, SAR is without any doubt not the
first choice for providing complete coverage of urban areas. For such purpose, sensors being capable of acquiring high-resolution
data in nadir view are better suited like optical cameras or airborne laserscanning devices. Nevertheless, there are at least
two kinds of application scenarios concerning city monitoring where the advantages of SAR play a key role: firstly, time critical
events and, secondly, the necessity to gather gap-less and regular spaced time series of imagery of a scene of interest.