One of the key technologies for achieving IIMEO’s goals is the processing of SAR data directly on the acquisition platform. This enables the rapid detection of disruptions regardless of the weather and time of day, while reducing the amount of data that needs to be sent back to Earth. The real-time SAR processor is at the heart of this, as it prepares the raw data for further analysis. The processed SAR images, which are georeferenced in near real-time, are then used to recognise changes in the area of interest.

The SAR images used for IIMEO are acquired in stripmap mode. In this mode, the platform follows a fixed path while the SAR sensor continuously scans the Earth’s surface at a fixed angle and captures radar data. The antennas are fixed and no adjustments are made during the scanning process. The SAR sensor scans the target area at a constant speed relative to the platform. The depth of the scanning area is determined by the elevation angle of the SAR antenna, the width of the scanning area by the azimuth angle of the antenna. The exposure time depends on the size of the scanned area. The range resolution is determined by the bandwidth of the radar, while the azimuthal resolution depends on the antenna length. In stripmap mode periodic pulses are sent out to generate a continuous strip of the SAR image. To avoid ambiguities, the pulse repetition frequency (PRF) must be higher than the Doppler bandwidth of the received signal.