Monthly Archives: January 2016

Increased Bandwidth Makes Possible Higher Resolution SAR Remote Sensing


ALOS-2 PALSAR L-band SAR intensity image of Chichawatni Irrigated Plantation region (black boundary) in Sahiwal District, Punjab province, Pakistan. The image is speckle-filtered sigma-nought dB image in false color. Data courtesy JAXA.

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.

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