min of the radio
telescope. In the absence of such information a value of 5o shall be taken. The percentage of time during
which the epfd level shall not be exceeded is mentioned in Note (1) of Table 1-2.
The Committee on Radio Astronomy Frequencies (CRAF) is a committee of
the European Science Foundation (ESF).
The World Radiocommunication Conference (Geneva, 2003),
considering
a) that adjacent or nearby primary service allocations have been made to the radio astronomy service, and to various space services, such as the fixed?satellite service (FSS), radionavigation satellite service (RNSS), mobile-satellite service (MSS) and broadcasting-satellite service (BSS), hereafter referred to as active space services;
b) that, in many cases, the frequencies used by the radio astronomy service (RAS) are chosen to study natural phenomena producing radio emissions at frequencies fixed by the laws of nature, so shifting frequency to avoid or mitigate interference problems may not be possible;
c) that Recommendation ITU-R SM.1633 provides a methodology for conducting, and a framework for documenting the results of, compatibility studies between active space service and passive service band-pairs;
d) that Recommendation ITU-R SM.1633 also provides the results of compatibility studies between a passive service and an active space service in certain adjacent and nearby bands;
e) that appropriate consultation between administrations has the potential to lead to the development of innovative solutions and to the rapid deployment of systems;
f) that, for technical or operational reasons, more stringent spurious emission limits than the general limits in Appendix 3 may be required to protect the RAS from active services in specific bands,
noting
a) that the additional burden of undertaking any technical examination should not be placed on the Radiocommunication Bureau;
b) that a consultation procedure, as contained in this Resolution, would not place an additional burden on the Radiocommunication Bureau;
c) that Recommendation ITU-R M.1583 provides a methodology based on the equivalent power flux-density (epfd) concept for calculation of interference resulting from unwanted emissions from non-geostationary (non-GSO) satellite systems of the MSS or RNSS into radio astronomy stations;
d) that Recommendation ITU-R S.1586 provides a methodology based on the epfd concept for calculation of interference resulting from unwanted emissions from non-GSO systems of the FSS into radio astronomy stations;
e) that Recommendation ITU-R RA.1631 provides antenna patterns to be used for compatibility analyses between non-GSO systems and RAS stations, based on the epfd
f) that Recommendation ITU-R RA.1513 provides acceptable levels of data loss to radio astronomy observations, stating in particular that the percentage of data loss caused by any system should be lower than 2%;
g) that some of the results documented in Recommendation ITU-R SM.1633 may be used as threshold levels to initiate the consultation procedure;
h) that the results of successful consultation between concerned administrations would ensure that the interests of both the active and passive services are considered;
i) that measures taken by active space services to protect radio astronomy stations from interference may result in increased costs and/or reduced capabilities for those services;
j) that conversely, not taking such measures may result in additional operating costs and reduced operational effectiveness for the radio astronomy stations concerned;
k) that the implementation of additional interference mitigation measures at the radio astronomy station may increase operating costs and reduce observational effectiveness;
l) that conversely, not implementing such measures may impose upon the active space services an additional cost burden and reduction in service capability;
m) that studies for some of the band-pairs listed in Recommendation ITU-R SM.1633 are still in progress,
recognizing
a) that unwanted emissions produced by stations of the active space services may cause unacceptable interference to stations of the RAS;
b) that, although some unwanted emissions from transmitters on space stations can be controlled through careful design methods and appropriate testing procedures, other unwanted emissions, such as narrowband spurious emissions, generated by uncontrollable and/or unpredictable physical mechanisms, may only be detected after the spacecraft is launched;
c) that there is an uncertainty in the pre-launch assessment of the levels of unwanted emissions;
d) that it is necessary to ensure an equitable sharing of burden for achieving compatibility between the active space services and the RAS;
e) that for those cases where difficulties are encountered in meeting the values in the Annex, a consultation procedure could be used to resolve the difficulties,
resolves
1 that an administration takes all reasonable steps to ensure that space stations being designed and constructed to operate in the bands in the Annex meet the values given therein at any radio astronomy station operating in the corresponding bands identified in the Annex;
2 that in the event that during construction and prior to launch it is determined that, after having considered all reasonable means, the unwanted emissions from the space station cannot meet the values given in the Annex, the administration that notified the space station contacts, as soon as possible, the administration operating the radio astronomy station:
a) to confirm that resolves 1 has been fulfilled; and
b) the concerned administrations enter into a consultation process in order to identify all practicable steps with a view to achieving a mutually acceptable solution;
3 that in the event, following the space station launch, an administration operating a radio astronomy station determines that, due to unexpected circumstances, a space station does not meet the values for unwanted emissions given in the Annex to this Resolution at that radio astronomy station, it contacts the administration that notified the space station, so that:
a) the administration that notified the space station confirms that resolves 1 has been fulfilled; and
b) the concerned administrations enter into a consultation process in order to identify further steps with a view to achieving a mutually acceptable solution;
4 that the radio astronomy stations to be taken into account in applying resolves 1, 2 and 3 are those which are operating in the frequency band(s) identified in the Annex to this Resolution and which are notified before the date of reception of the advance publication information of the space station to which this Resolution applies;
5 that the space stations to be considered in the application of the above resolves are those designed to operate in the space service frequency bands listed in the Annex for which advance publication information is received by the Radiocommunication Bureau following the entry into force of the Final Acts of this conference;
6 that the objective of the consultation process in resolves 1, 2 and 3 is to achieve a mutually acceptable solution, using as guidance Recommendation ITU-R SM.1633 and any other ITU?R Recommendations deemed relevant by the concerned administrations;
7 that the Radiocommunication Bureau shall make no examination or finding with respect to this Resolution under either Article 9 or 11,
invites administrations
1 to take all appropriate and practicable steps, from the design phase onward, to ensure that unwanted emissions are minimized from space stations that are planned to operate in one or more space service allocations, in order to avoid exceeding the threshold levels of unwanted emissions identified in the Annex to this Resolution at any radio astronomy station;
2 to take all practicable steps, from the design phase onward, to minimize the sensitivity of radio astronomy stations to interference and to take into account the need to implement interference mitigation measures.
ANNEX TO RESOLUTION 739 (WRC-03)
The unwanted emission threshold levels applicable to geostationary space stations are given in Table 1-1 in terms of power flux-density (pfd) in a reference bandwidth produced at a radio astronomy station.
In Table 1-1 the unwanted emission threshold levels given in the fourth, sixth and eighth columns (associated with the reference bandwidth contained in the adjacent columns) should be met by space stations operating in the bands indicated in the second column at the radio astronomy station operating in the band mentioned in the third column.
The unwanted emission threshold levels applicable to space stations of non-geostationary systems are given in Table 1-2 in terms of the equivalent power flux-density (epfd), produced at a radio astronomy station in a reference bandwidth, not to be exceeded during a given percentage of time, over the whole sky.
In Table 1-2 the epfd value given in the fourth, sixth and eighth columns (associated with the reference
bandwidths contained in the adjacent column) should be met by space stations operating in the bands indicated
in the second column at the radio astronomy station operating in the band mentioned in the third column.
The epfd value at a given radio astronomy station shall be evaluated by using the antenna pattern and the
RAS maximum antenna gain given in Recommendation ITU?R RA.1631. Guidance on the calculation of epfd can be
found in Recommendations ITU-R S.1586 and ITU-R M.1583. The elevation angles of the radio astronomy stations
to be taken into account in the epfd calculation are those higher than the minimum elevation angle
min of the radio
telescope. In the absence of such information a value of 5o shall be taken. The percentage of time during
which the epfd level shall not be exceeded is mentioned in Note (1) of Table 1-2.
TABLE 1-1
pfd thresholds for unwanted emissions from geostationary space stations at a radio astronomy station
| Space service | Space service band | Radio astronomy band | Single dish, continuum observations | Single dish, spectral line observations | VLBI(1) | ||
| pfd(2) | Reference bandwidth | pfd(2) | Reference bandwidth | pfd(2) | |||
| MHz | MHz | dB(W/m2) | MHz | dB(W/m2) | kHz | dB(W/m2) | |
| BSS (s-to-E) MSS (s-to-E) | 1 452-1 492 1 525-1 559 | 1 400-1 427 | 180 | 27 | 196 | 20 | 166 |
| MSS (s-to-E) MSS (s-to-E) | 1 525-1 559 1 613.8-1 626.5 | 1 610.6-1 613.8 | NA | NA | 194 | 20 | 166 |
| BSS (s-to-E) FSS (s-to-E) | 2 655-2 670 | 2 690-2 700 | 177 | 10 | NR | 25 | 161 |
| FSS (s-to-E) | 2 670-2 690 | 2 690-2 700 (in Regions 1 and 3) | 177 | 10 | NR | 20 | 161 |
| GHz | GHz | | | | | | |
| BSS (s-to-E) | 21.4-22.0 | 22.21-22.5 | NR | NR | NR | 250 | 128 |
NA: Not applicable, measurements of this type are not made in this band.
NR: No result available.
(1) The reference bandwidth used for spectral line observations has also been used as reference bandwidth for very long baseline interferometry (VLBI) observations. In VLBI bands, where no spectral line observations are conducted, the reference bandwidth for VLBI observations has been determined using the assumption of Recommendation ITU-R RA.769 for a typical spectrometer channel (3 km/s).
(2) Integrated over the reference bandwidth with an integration time of 2 000 s.
TABLE 1-2
| Space service | Space service band | Radio astronomy band | Single dish, continuum observations | Single dish, spectral line observations | VLBI(1) | ||
| epfd(3) | Reference bandwidth | epfd(3) | Reference bandwidth | epfd(3) | |||
| MHz | MHz | dB(W/m2) | MHz | dB(W/m2) | kHz | dB(W/m2) | |
| MSS (s-to-E) | 1 613.8-1 626.5 | 1 610.6-1 613.8 | NA | NA | 258 | 20 | 230 |
NA: Not applicable, measurements of this type are not made in this band.
(1) These epfd thresholds should not be exceeded for more than 2% of time.
(2) The reference bandwidth used for spectral line observations has also been used as reference bandwidth for VLBI observations. In VLBI bands, where no spectral line observations are conducted, the reference bandwidth for VLBI observations has been determined using the assumption of Recommendation ITU-R RA.769 for a typical spectrometer channel (3 km/s).
(3) Integrated over the reference bandwidth with an integration time of 2 000 s.