Radio tomography of the ionosphere

An overview of tomographic approaches to ionospheric remote sensing in the radio-wave range is provided. Tomographic methods are divided into deterministic and statistical ones. Deterministic tomography problems can be subdivided into ray radio tomography and diffraction radio tomography. The statistical radio tomography approach is used when it is necessary to reconstruct the statistical structure of a great number of inhomogeneities, on the basis of measurements of field statistics (instead of one realization of the reconstruction of an inhomogeneity). Methods of solving radio tomography problems, and their connection with inverse scattering problems, are considered. The results of some initial experiments that show the possibilities of the radio tomography approaches are described. Future applications and problems are discussed.<>