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www.southgatearc.org
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Page last updated on:
Saturday, October 16, 2010
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ESA satellite suffers interference from terrestrial stationsESA's SMOS satellite has been plagued by interference from radar, TV and radio transmissions in what should be a protected band. The ESA website reports that data from the Soil Moisture and Ocean Salinity (SMOS) mission has been badly contaminated by radio-frequency interference – or RFI for short. At times, this interference was effectively blinding the instrument, rendering the data over certain areas unusable. SMOS carries a passive radiometer that operates at 1400–1427 MHz in the L-band of the electromagnetic spectrum to capture snapshots of 'brightness temperature'. These snapshots correspond to microwave radiation being emitted from Earth's surface and relate to the amount of moisture in soil and salinity in the ocean. This information is needed to improve our understanding of Earth's water cycle. According to radio regulations set by the International Telecommunications Union, this frequency band is reserved for the Earth Exploration Satellite Service, space research and radio astronomy. However, SMOS data revealed that there were many incidences of signals within this protected band, particularly in southern Europe, Asia, the Middle East and some coastal zones. The transmissions contaminating the data were due to two main reasons: either emissions in adjacent bands that were leaking into the protected region owing to excessive power levels, or illegal transmissions within 1400–1427 MHz. So far, the main culprits appear to be TV transmitters, radio links and networks such as security systems. Also terrestrial radars appear to cause interference. To ensure that the excellence of the mission would not be compromised, ESA embarked upon the tricky and lengthy process of having the illegal transmissions shut down and the excessive out-of-band emissions reduced. Read the full ESA story Space Flight Now
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