Radio tomography imaging based on navigation systems

Methods of radio tomography (RT) based on the low- and high-orbital navigational systems and radio occultation data are considered. Examples of RT imaging of the ionosphere in different regions of the world illustrate the use of low-orbital and high-orbital radio tomography (LORT and HORT, respectively) separately and in combination with each other. RT methods allow studying of various ionospheric structures: troughs, travelling ionospheric disturbances (TIDs), spots of enhanced ionizations, patches, blobs, wavelike structures, manifestations of particle precipitation. The possibilities for the application of RT systems together with other methods of UV and radio sounding are discussed.