1. Main properties of radar images

1.1 Data sources

Radar instruments were placed on aircraft as early as the 1940s, so very soon after their invention, and most of the progress in radar imaging was made using airborne images, including the first tests of radar interferometry . Even today, airborne systems can offer a wealth of unique combinations between interferometry and polarimetry, multiple antennas enabling various types of interferometry (perpendicular and along-track, see § 7.5.3), multiple wavelengths. In fact, the relative abundance of power of an aircraft, its large payload, and its data-recording...