Filing info for Sentinel-1A radar ground images

Sentinel-1A, the first satellite in the Sentinel-1 constellation, was launched April 3, 2014. The Sentinel-1 satellites (Sentinel-1A, Sentinel-1B, and Sentinel-1C) are sun-synchronous polar-orbiting satellites that operate day and night performing C-band synthetic aperture radar (SAR) imaging. The Sentinel-1 satellites operate in four imaging modes with different resolutions (down to 5 meters) and coverage (up to 400 kilometers). The Sentinel-1 satellites provide dual polarization capability and short revisit times. Sentinel-1A Ground Range Detected (GRD) products consist of focused SAR data that has been detected, multi-looked and projected to ground range using the Earth ellipsoid model WGS84. The ellipsoid projection of the GRD products is corrected using the terrain height and is specified in the product’s general annotation. The terrain height used varies in azimuth and it is constant in range (only the terrain height of first subswath is considered for Interferometric Wide (IW) and Extra Wide (EW) swath modes). Ground range coordinates are the slant range coordinates projected onto the ellipsoid of the Earth. Pixel values represent detected amplitude. Phase information is lost. The resulting product has approximately square resolution pixels and square pixel spacing with reduced speckle at a cost of reduced spatial resolution. For IW and EW GRD products, multi-looking is performed on each burst individually. All bursts in all sub-swaths are then seamlessly merged to form a single, contiguous, ground range, detected image per polarization. The products in this collection are ISO compliant XML metadata created by the Alaska Satellite Facility Distributed Active Archive Center from the associated Sentinel-1A SAFE format product.