The Soil Moisture and Ocean Salinity (SMOS) mission are an European Space Agency's (ESA) Earth Explorer Mission, with national contributions provided by the French Space Agency, the Centre National d'Etudes Spatilales (CNES) and the Spanish Centro para el Desarrollo Tecnologico Industrial (CDTI). The main objective of SMOS is to produce global maps of Soil Moisture and Ocean Salinity over the Earth, key variables used in predictive hydrological, oceanographic and atmospheric models. SMOS was launched on November 2009 and has just completed the Commissioning Phase in May 2010. The satellite carries a single payload on board, MIRAS, the first spaceborne Microwave Imaging Radiometer with Aperture Synthesis in two dimensions which operates within the Earth Exploration Satellite Service (EESS) passive band at 1400-1427 MHz. SMOS observations obtained to date provide evidence of Radio-Frequency Interference (RFI) in the passive band at levels that prevent geophysical measurements. Based on radiometer out-of-band rejection characteristics, the current analysis of the retrieved data and additional ground measurements of identified RFI sources, there is evidence that the observed RFI are mainly due to man-made emissions falling within the EESS (passive) protected band. These emissions are either illegal in-band emissions inside the protected band or excessive unwanted emission from systems operating in the adjacent bands. Using SMOS data collected during the Commissioning Phase, the authors have mapped the interferers over the ground surface around the globe as well as the probability of SMOS being contaminated. Calibration and careful examination of SMOS data confirm the presence of strong RFI sources over Southern Europe, Middle East and Central Asia. The RFI sources that were detected, identified and finally switched off in Spain and Finland were all coming from unauthorised emissions in the 1400-1427 MHz passive band. There are solid indications that some interferers may consist of unwanted emissions from terrestrial radar operating in the 1215-1400 MHz radiolocation band and other terrestrial sources operating in the upper neighbouring band, in particular for those whose position correlates well with known radar installations. This paper also addresses the regulatory provisions for unwanted emissions falling into the 1400-1427 MHz passive band. The latest World Radio Conference (WRC) in 2007 adopted recommended levels of out-of-band emissions failing within this passive band and an ongoing action at European level aims to make these levels compulsory in order to have an adequate and long-term protection of this essential passive band. Payload data and methods used to identify and discrimination between different interferers are presented, together with the first attempts to characterise these RFI sources and their location. While the knowledge of the location of the interferers is progressing, ESA has initiated contacts with national administrations responsible for spectrum management to support the identification of these RFI sources. The status of this ongoing action is presented.


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    Titel :

    Characterisation of SMOS RF interferences in the 1400-1427 MHz Band as detected during the commissioning phase


    Weitere Titelangaben:

    Kennzeichnung von SMOS-Hochfrequenzinterferenzen im 1400 - 1427 MHz-Band während des Auftretens in der Kommissionierphase


    Beteiligte:
    Daganzo, E. (Autor:in) / Pla, J. (Autor:in) / Kerr, Y. (Autor:in) / Neira, M. Martin (Autor:in) / Oliva, R. (Autor:in) / Marelli, E. (Autor:in) / Mecklenburg, S. (Autor:in) / Rommen, B. (Autor:in) / Brown, M. (Autor:in) / Richaume, P. (Autor:in)


    Erscheinungsdatum :

    2011


    Format / Umfang :

    12 Seiten, 14 Bilder, 1 Tabelle, 9 Quellen



    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch




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