At the recent ITU World Radiocommunication Conference (WRC 2015) held in Geneva, Switzerland, in Nov. 2015, earth remote sensing by Synthetic Aperture Radar (SAR) satellites has received a significant boost in terms of technology. This advancement has come about as a result of the WRC approval of expansion of the bandwidth reserved for satellite-based SAR remote sensing from 600 MHz to 1200 MHz. This increase in allocated bandwidth is actually an increase in the chirping bandwidth, which improves the cross-track (range) resolution of the SAR image. The chirped (frequency modulated) signal is used for enhanced resolution imaging in the cross-track (range) direction, while the Doppler spectrum generated due to satellite motion is used for enhanced resolution imaging in the along-track (azimuth) direction. The increased bandwidth also opens up opportunities for operational-level multi-band SAR imagery, in terms of multiple frequency bands for imaging and full quad-polarimetry (HH, HV, VH, VV) data acquisition.
See more details here: