On the use of mapping operators in SAR and SAS

The process of reconstructing a two-dimensional image of the earth´s surface or the sea floor from a sequence of pulse echoes collected by a synthetic aperture radar (SAR) or sonar (SAS) is well established. There are differences between radar and sonar mainly stemming from the much slower speed of sound propagation in water compared with that of electromagnetic propagation in air. Of all the strip-map algorithms in use, the wavenumber algorithm appears to be the most general to both radar and sonar as it has fewer approximations and lends itself to an efficient description using a new mathematical convention which we call mapping operators. We show how these mapping operators might be used to form SAR/SAS image reconstruction algorithms for both strip-map and spotlight synthetic aperture imaging systems.