Platform options of free-flying satellites, UAVs or the International Space Station for remote sensing assessment of the littoral zone

Over the years, making or creating a choice for a specific platform from which to conduct remote sensing observations of specific targets brings in many factors related to the target characteristics and how the data are going to be used. Attempts to measure Earth's diverse objects have generated a wide range of platform alternatives, from geostationary satellites to low-flying aircraft. Now several additional options possessing unique attributes are available: the International Space Station (ISS) and Un-inhabited Aerial Vehicles (UAVs). This paper explores some of the tradeoffs among these alternatives for the special problem of remotely sensing the littoral zone, but especially the shallow ecosystems. Though the surface area of the littoral zone is relatively large, it is geographically disbursed and somewhat linear. Also, the spatial, spectral and temporal variability of ecosystems in this zone is very high, and signals are masked by the overlying water column. Ideally, a frequent revisit time would be desirable to monitor their health and changing condition. These characteristics place important constraints on platform choice as one tries to design a system to monitor these critical ecosystems and provide useful information for managing them. This paper discusses these tradeoff issues as offered mainly by three platform choices: free-flying satellites, ISS, UAVs and other aircraft.