The Recommendation considering that the radio astronomy service (RAS), the Earth exploration-satellite service (EESS) (passive) and space research service (SRS) (passive) are based on the reception of natural emissions at much lower power levels than are generally used in other radiocommunication services; that, due to these low received power levels, these passive services are generally more susceptible to interference from unwanted emissions than other services.
ITU-R SM.1633 FRENCH-2003 Referenced Document
ITU-R RA.1513 Levels of data loss to radio astronomy observations and percentage-of-time criteria resulting from degradation by interference for frequency bands allocated to the radio astronomy service on a primary basis*， 2015-03-01 Update
ITU-R RA.314 Preferred frequency bands for radio astronomical measurements (Study Group 7; Document 7/1006-E: February 20@ 2003)
ITU-R S.1557 Operational requirements and characteristics of fixed-satellite service systems operating in the 50/40 GHz bands for use in sharing studies between the fixed-satellite service and the fixed service*
ITU-R S.1586 Calculation of unwanted emission levels produced by a non-geostationary fixed-satellite service system at radio astronomy sites*， 2007-01-01 Update
ITU-R SA.1029 Interference criteria for satellite passive remote sensing
ITU-R SM.1541 Unwanted emissions in the out-of-band domain*， 2015-08-01 Update
ITU-R SM.1542 Protection of passive* services from unwanted emissions