<title>Volumetric imaging system for the ionosphere (VISION)</title>

Abstract

The Volumetric Imaging System for the Ionosphere (VISION) is designed to use limb and nadir images to reconstruct the three-dimensional distribution of electrons over a 1000 km wide by 500 km high slab beneath the satellite with 10 km x 10 km x 10 km voxels. The primary goal of the VISION is to map and monitor global and mesoscale (&gt; 10 km) electron density structures, such as the Appleton anomalies and field-aligned irregularity structures. The VISION consists of three UV limb imagers, two UV nadir imagers, a dual frequency Global Positioning System (GPS) receiver, and a coherently emitting three frequency radio beacon. The limb imagers will observe the O II 83.4 nm line (daytime electron density), O I 135.6 nm line (nighttime electron density and daytime O density), and the N<SUB>2</SUB> Lyman-Birge-Hopfield (LBH) bands near 143.0 nm (daytime N<SUB>2</SUB> density). The nadir imagers will observe the O I 135.6 nm line (nighttime electron density and daytime O density) and the N<SUB>2</SUB> LBH bands near 143.0 nm (daytime N<SUB>2</SUB> density). The GPS receiver will monitor the total electron content between the satellite containing the VISION and the GPS constellation. The three frequency radio beacon will be used with ground-based receiver chains to perform computerized radio tomography below the satellite containing the VISION. The measurements made using the two radio frequency instruments will be used to validate the VISION UV measurements.