ITU-R QUESTION 2267-1997 Frequency sharing between the radio astronomy service and other services in bands above 70 GHz《无线电天文学服务与其他服务在70千兆赫以上频段之间的频率共享》.pdf

《ITU-R QUESTION 2267-1997 Frequency sharing between the radio astronomy service and other services in bands above 70 GHz《无线电天文学服务与其他服务在70千兆赫以上频段之间的频率共享》.pdf》由会员分享，可在线阅读，更多相关《ITU-R QUESTION 2267-1997 Frequency sharing between the radio astronomy service and other services in bands above 70 GHz《无线电天文学服务与其他服务在70千兆赫以上频段之间的频率共享》.pdf（2页珍藏版）》请在麦多课文档分享上搜索。

1、QUESTION ITU-R 226/7*Frequency sharing between the radio astronomy service and other services in bands above 70 GHz (1997) The ITU Radiocommunication Assembly, considering a) that a large number of atomic and molecular spectral lines are observed at frequencies above 70 GHz, and that many of these l

2、ines are of great importance to astronomy but only few fall within bands allocated to radio astronomy; b) that these spectral lines along with continuum observations provide unique information about star formation, including the formation of planets in other solar systems, the existence of pre-biolo

3、gical molecules and extra-terrestrial life, the physics and chemistry of the interstellar medium, the history of the universe, and about other astrophysical processes of great interest; c) that Doppler-shifted lines of great interest for the study of the early universe have been detected at frequenc

4、ies well outside the bands allocated to radio astronomy; d) that sharing between radio astronomy observatories and ground-based transmitters is facilitated in the mm-wave and submm-wave spectral regions by topography, by the atmospheric absorption bands, and by the natural attenuation provided by at

5、mospheric gases; e) that there are only a small number of mm-wave and submm-wave observatories operating worldwide; f) that several large mm-wave and submm-wave telescopes, which will incorporate the most advanced technology, are planned or are under construction, and that they represent large colla

6、borative scientific investments by the participating countries; g) that mm-wave and submm-wave observatories are, wherever practicable, located in isolated remote sites, to take maximum advantage of extremely dry atmospheric conditions and a low interference environment; h) that geographical sharing

7、 between the radio astronomy service and other services may be feasible with the creation of protection zones by national administrations; and j) that there is extensive development being carried out to provide radiocommunication services at mm-wavelengths, e.g. for the transmission of large volumes

8、 of data, and for mass market devices such as vehicular radars, decides that the following Question should be studied 1 What are the services with which the radio astronomy service can share frequency bands above 70 GHz? 2 What are the conditions for frequency sharing between radiocommunication serv

9、ices above 70 GHz using active and passive systems? _ *In the year 2009, Radiocommunication Study Group 7 extended the completion date of studies for this Question. - 2 - further decides 1 that the results of the decides above should be the subject of a report to be prepared as a contribution to the Report of the Conference Preparatory Meeting to the WRC-07.