Three-dimensional computerized ionospheric tomography using volumetric constraints

A new algorithm for the reconstruction of three-dimensional images of ionos pheric electron density using volumetric a priori information is presented in this paper. This method relies upon the total electron content (TEC) dat a measured by an ionospheric tomography system to derive necessary distribu tion-related information from a priori ionospheric images for projection do main and image domain volumetric correction processes. It involves extracti on of shape information from a priori ionospheric images on an extremely lo calized basis to simultaneously satisfy measured TEC data and the need for coherent, convergent reconstruction guidance, necessary for the limited ang le tomography system. The algorithm uses three-dimensional polar geometry f or computerized ionospheric tomography (CIT) which permits direct use of sl ant TEC data without the interpolations that are necessary for conventional two-dimensional imaging of the ionosphere. Reconstructions based on data r ecorded in two recent CIT campaigns are also presented.