Synthetic aperture radar (SAR) technology operates through the concentration of radar pulses through an anteanna, and analyzing the return wave formation. Today’s AR technology returns a finer spatial resolution, with resolution of millimeters achieved in labs, and with 1 meter resolution achievable on such commercial satellites as Astrium’s TerraSAR-X or Radarsat’s Radarsat-2.
Persistent surveillance is only possible when there are no interruptions. Radar has a distinct advantage of being able to collect imagery regardless of weather, and during both day and night. The ability to revisit the same place repeatedly, and get the same imagery quality regardless of weather, provides an advantage for change detection applications.
Radar data is also unique in its ability to pick up the surface of water, and disturbances. With this ability comes the application to monitor and track ships, to the point where the size and direction of a ships wake help determin both its speed and heading in order to pinpoint current location.
Among the other advantages and applications of radar satellite imagery are:
While the speckle structure of SAR images take some getting used to in order to correctly interpret the images, SAR is an important earth observation input that fills in many data gaps that exist with traditional image-based sensors.