Volumetric Imaging System for the Ionosphere (VISION)

摘要

The Volumetric Imaging System for the Ionosphere (VISION) utilizes 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 (> 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 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 N2 Lyman-Birge-Hopfield (LBH) bands near 143.0 nm (daytime N2 density). The nadir imagers observe the O I 135.6 nm line (nighttime electron density and daytime O density) and the N2 LBH bands near 143.0 nm (daytime N2 density). The GPS receiver monitors the total electron content between the satellite carrying VISION and the GPS constellation and detects scintillation. The three frequency radio beacon will be used with ground-based receiver chains to perform computerized radio tomography below the satellite. Measurements made using the two radio frequency instruments may also be used for on-orbit calibration and validation of the VISION UV measurements.