Synthetic Aperture Radar (SAR) is an active microwave imaging method. It op
erates independently of Sun illumination and cloud coverage. Current spaceb
orne systems use wavelengths of 3 to 25 cm and achieve resolutions of 10 to
50 m. The paper attempts to explain the basic SAR imaging principles using
a minimum of mathematics. Emphasis is put on the particular properties of
SAR images that should be understood before interpreting these data.