Earth Observation Satellites (EOS) are orbital devices specially designed for surveillance and monitoring of the Earth in order to obtain an in-depth understanding of the layers and of the earth system. Basically EOS are grouped into synchronized sets of polar orbiting satellites for permanent observation work towards the land section, water surface, atmosphere and biosphere. EOSs are used at low altitudes (around 800km) to get a better portrait of intended targets. 1.2 History The first impulse to innovate an observation satellite dates back to the First World War, when aircraft were used to scan enemy areas through simple cameras. This was further advanced during World War II as aerial photos were invented for mapping purposes. Subsequently, image processing was enriched with digital chorological matrix systems to produce better quality data. Indeed, on October 4, 1957, the Soviet Union launched the first satellite into space. This created a competitive market for the United States and a real threat, as they called it the “missile gap”. A year later, on January 31, the US Department of Defense launched Explorer 1. Competition led the technologies to continue to become sophisticated as civilian satellites emerged on the market, such as weather observation satellites (METEOSAT and NOAA)[1]. As a matter of fact, the first weather satellite was launched by NASA in 1960 (TRIOS 1) and launched the first spin-stabilized communications satellite in 1966. The awareness that these satellites created for civilization has been well recognized by all researchers and scientists to develop and improve technology to meet human needs in all aspects of life. In fact, since 1982, NOAA satellites have helped...... middle of paper ...... a wide variety of chemical limitsV. Highly sensitiveVI. No regulation of spectrumVII. Low energy consumptionVIII. Higher bandwidth open3.2 ApplicationI. Air operations II. Quantum Distribution [6]Comparison 4.0Table 5: SAR vs Optical Comparison# Optical SAR1 wavelength 1 cm – 1 m 1 micron2 visibility Can see through clouds, storms and sky objects. [10] The wavelength cannot pass through clouds.3 Illumination has its own illumination source (signal band) Requires external thermal radiation to illuminate the observed target4 Imaging time Image quality is independent of time of day [7] Requires sunlight for best image quality5 Side sensors look straight down6 Working range Flat space Single point or point distribution [8]7 Color image Black and white Color8 Representation of small objects Inaccurate and unclear [9] May provide better detail