Multisource volumetric tomography for over-the-horizon radar

This paper presents a new technique for the mapping of ionospheric electron density distributions for determining ambient HF radio propagation charact eristics necessary for applications such as over-the-horizon-radar (OTHR). The multisource volumetric inversion technique (MSVIT) combines information from conventional ionospheric probes used for OTHR, such as quasi-vertical incidence and oblique backscatter ionosondes, with total electron content data obtained by computerized ionospheric tomography (CIT), to form three-d imensional maps of ionospheric electron density distribution. MSVIT is an i terative reconstruction technique that draws on the wide-area coverage of V HF-UHF data from a CIT imaging system colocated with an OTHR system to enha nce the reliability of sector-wise localized predictions of HF propagation conditions. A detailed analysis of the MSVIT algorithm together with simula tions using the international reference ionosphere model of 1990 and experi mental data from recent CIT campaigns shows that MSVIT has considerable pot ential for improving the quality of OTHR operations.