Data measures for three-dimensional computerized ionospheric tomography systems

Computerized ionospheric tomography (CIT) is an emerging technique that produces two and three-dimensional images of the electron distributions in the ionosphere. The limiting factor for CIT reconstructions is the inability to accurately estimate their vertical profiles due to the geometry of the CIT systems, which limits the amount of information detected at large projection angles. A relationship exists between the amount of information that is gathered at a particular projection angle, and the positions of the ground station receivers in the data acquisition system. The proper placement of these ground station receivers can increase the information content of the dataset, and consequently increase the resolution of the resulting images. In order to measure the effect of varying the placement of the ground station receivers, a resolution metric is needed. This paper presents a resolution measure based on projections that enables observation of the information content as a function of the ray path angle. This resolution measure can be used in the development of CIT systems as well as in the evaluation of existing system configurations.