Signal Processing Methods for the Different Applications
The exact SAR inversion formulas, which are basic to meter wave SAR, were originally derived by Lars-Erik Andersson in collaboration with the author around 1985. The account of SAR inversion principles is now augmented to include moving targets. Again, given an exact large bandwidth formulation.
The difficulty meter wave processing lies not least in how the navigational data shall be used to compensate for a nonlinear radar aircraft path. It turns out that for meter wave SAR (just as for high resolution microwave SAR) very high accuracy is required for synthetic aperture. Methods, relying on inertial measurements, satellite navigation data, as well as autofocusing methods, are discussed, indicating how these data are utilized in computer efficient algorithms.
Also, methods are derived for meter wave SAR target detection. Rather than attempting any overview of the many approaches which have been attempted, the account provides in depth insight in three explicit methods, addressing respectively detection of stationary targets, moving target detection and subsurface targets. The three methods are all examples of what night be termed multidata detection, i.e. target detection achieved by comparing SAR images collected under different circumstances (in time, i.e. change detection, antenna location on the aircraft for moving targets, and polarization for subsurface targets). Accounts of experiments are provided, showing how the methods have been successfully adopted.