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DataTake 31.056

Date: February 15, 2000
Site: Tasmania

This image is pertinent to the Freycinet peninsula in the East zone of Tasmania (approximately 42° Lat. S, 148° Long. E) where is located the Freycinet National Park. The image dimensions are 42 Km ´ 32 Km.

The images presented have been generated by an innovative Italian real time processor. The original four bit coded received raw signal is reformatted and recoded at one bit; then is processed in real time with a similar 1-bit code filter function. The filter convolution is implemented via a simple and inexpensive hardware consisting of phase shifters and adders. Downsizing and power reduction for this processor is possible, thus making the machine a good candidate for onboard processing.

The four images presented represent:

Medium Resolution Image (MRI): the gray values represent the strength of the reflected radar signal; the stronger the back-scattering the brighter the image. Two such images are needed to obtain the Interferogram.

alta_en.jpg (5088 byte)

jpgrdi o1.21.29small.jpg (21621 byte)

Interferogram: the different colors represent the different phase values; the steeper the slopes, the closer the fringes. Height contour levels can be inferred from fringes

jpgwrf o1.21.29small.jpg (26919 byte)

Digital Elevation Model (DEM): is a representation point by point of the surface height obtained from Interferogram; the height increases from blue to red.

jpgdem o1.21.29small.jpg (26831 byte)

DEM-3D: tri-dimensional view.

jpgdem 3d o1.21.29small.jpg (17666 byte)

The DEM-3D shows steep mountains walls which can be also clearly seen from the close fringes on the interferogram. The same evaluations can be done looking to the DEM different colors.

These images were acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour launched on February 11,2000. SRTM uses the same radar instrument that comprises the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designated to collect three dimensional measurements of nearly 80 percent of the earth surface. To collect the 3-D data , engineers added a 60 meter long (200 feet) mast, an additional C-band antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), The National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD) and the German and Italian Space Agencies. It is managed by NASA’s Jet Propulsion Laboratory, Pasadena, CA, for NASA’s Earth Science Enterprise, Washington, DC.