Very High Resolution (VHR) satellite systems are platforms whose sensors acquire high geometric resolution images. Since 1972, when the first satellite was launched (Land sat ERTS), the spatial resolution of the satellite image has increased, making Ground Sample Distance (GSD) reaching 0.30 m at Nadir in panchromatic images. In this paper, after a brief introduction, concepts relative to orbits, types of sensors and resolutions are reported. Geostationary and sun-synchronous orbits are described; difference between push-broom and whisk-broom sensors are reported; the definition of the geometric, the radiometric and the temporal resolutions are listed. In the end, the characteristics of the most common VHR commercial optical satellite are mentioned: IKONOS-2, QuickBird-2, SPOT-5, GeoEye-1, WorldView-2 and WorlView-3 satellites.
Pasquale, P. M. (2016). Very high resolution optical satellites: An overview of the most commonly used. American Journal of Applied Sciences. Science Publications. https://doi.org/10.3844/ajassp.2016.91.99