Introducing: A Layman's Interpretation Guide to Synthetic Aperture Radar (SAR) data

摘要

Interpretation of optical satellite data is intuitive to many users as optical instruments function similar to the human eye - they are passive sensors which record reflected visible and infra-red light from the sun. Radar sensors, on the other hand, are active system that operate in the microwave domain of the electromagnetic spectrum. Microwaves are not visible to the human eye and provide a very different view of the world from what we are used to. Different, but not necessarily difficult. This "layman's" user guide was developed by soloEO, the Committee on Earth Observation Satellites (CEOS) and the GEO Global Forest Observations Initiative (GFOI) to provide users who have little or no experience of spaceborne Synthetic Aperture Radar (SAR) data with a simple reference document that outlines some basic concepts of radar remote sensing in a simple (non-electro engineering!) manner. Common radar terms such as radar wavelength, polarisation and sigma-0 are explained, as well as some of the basic backscatter mechanisms that explain how the radar signals interact with the ground. The guide also presents some commonly used SAR datasets, and provides some examples of how a few different land cover types may appear in Sentinel-1 and ALOS-2 PALSAR-2 SAR imagery. The guide does however not go into the depths of microwave theory or radar processing (there is plenty of literature covering that) as expert knowledge today no longer should need to be a major concern for most users. Many space data providers are also now moving towards the provision of so called analysis-ready data (ARD) also for SAR, which can be used and integrated with other data sources with little or no need for users to undertake their own processing. The guide is available free of charge for download at http://ceos.org/ard/fiIes/Laymans_SARInterpretation_Guide_2.0.pdf.