In the last years, amongst all the remote sensing scientific activities, the Earth observation is having a great success.

This is both because of the remarkable progresses in the spatial missions field and the technological progress reached in antennas projecting and building for the Earth observation, antenna that have flown or still fly on satellites or spatial vectors as Space Shuttle.

       Courtesy of NASA/JPL
      Wadi Kufra, Libya

In this field, Radar and, in particular, SAR antennas (Synthetic Aperture Radar) are really becoming more and more interesting. A Radar antenna has the characteristic to acquire data almost everywhere and in every time, either with good or bad weather conditions and either with daylight or darkness on the observed area. As a matter of fact, the electromagnetic waves sent out from these antennas in some frequencies can pass the clouds through and, in some conditions, vegetation, ice or particularly dry sand as well. By this instrument, then, it is possible to observe what is under a dense rain vegetation or under the desert sand. 

Courtesy of NASA/JPL
Nile River, Sudan

The Radar images study allowed the scientists to discover really many archaeological areas as the riverbed that flowed in the Sahara desert millions of years before the Nile existed or the lost town of Ubar or the archaeological site of Angkor.

In some cases, finally, the Radar is the only mean the scientists have to observe some regions of the Earth surface particularly hard to reach.

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