Obtaining high resolution in transionospheric spaceborne VHF-band SAR for Earth remote sensing

At present spaceborne synthetic aperture radar (SARs) operate in the microwave (centimetre and decimetre) band. When used for remote sensing of the Earth's surface, they provide valuable data. However, these SARs appear to be ineffective if it is required to view natural formations and other objects located below and/or under the surface layer. This data are necessary to solve various economical, commercial and ecological problems. The authors show that in principle it is possible to overcome the resolution limitations in transionospheric VHF SARs by means of adaptive processing of received signals at the SAR output. They consider respective algorithms for adaptive compensation for the distortions and their simulation with the use of complex data from an airborne VHF SAR and records of actual phase fluctuations of a VHF signal passing through the ionosphere.