2929thth October 2004 October 2004 ESF Workshop, CagliariESF Workshop, Cagliari

WRC-07 and WRC-10 WRC-07 and WRC-10 Agenda Items Important for Agenda Items Important for

Radio AstronomyRadio Astronomy

WRC-07 and WRC-10 WRC-07 and WRC-10 Agenda Items Important for Agenda Items Important for

Radio AstronomyRadio Astronomy

Jim CohenJim Cohen Jim CohenJim Cohen

Jodrell Bank ObservatoryJodrell Bank Observatory

University of ManchesterUniversity of Manchester

Jodrell Bank ObservatoryJodrell Bank Observatory

University of ManchesterUniversity of Manchester

2929thth October 2004 October 20042929thth October 2004 October 2004

2929thth October 2004 October 2004 ESF Workshop, CagliariESF Workshop, Cagliari

WRC-07 agenda items 1.7, 1.8, 1.11, 1.17, 1.21

WRC-10 agenda item 2.2 (sub-mm bands)

Radio-Quiet Zones

WRC-07 agenda items 1.7, 1.8, 1.11, 1.17, 1.21

WRC-10 agenda item 2.2 (sub-mm bands)

Radio-Quiet Zones

Outline of TalkOutline of TalkOutline of TalkOutline of Talk

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1.7 to consider the results of ITU-R studies regarding sharing between the mobile-satellite service and the space research service (passive) in the band 1 668-1 668.4 MHz, and between the mobile-satellite service and the mobile service in the band 1 668.4-1 675 MHz in accordance with Resolution 744 [COM5/12](WRC-03);

WRC-03 allocated 7 MHz to MSS (INMARSAT): studies of SRS and MS sharing afterwards!

Space-based VLBI (very long baseline interferometry) telescopes operate in the space research (passive) service, since 1997 (Japanese HALCA 8-m dish).

1.7 MSS and SRS (passive)

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1.8 High Altitude Platform Stations (HAPS)

1.8 to consider the results of ITU-R studies on technical sharing and regulatory provisions for the application of high altitude platform stations operating in the bands 27.5-28.35 GHz and 31-31.3 GHz in response to Resolution 145 [COM5/17] (WRC-03), and for high altitude platform stations operating in the bands 47.2-47.5 GHz and 47.9-48.2 GHz in response to Resolution 122 (Rev.WRC-03);

In Bhutan, Korea (Rep. of), the Russian Federation, Indonesia, Iran (Islamic Republic of), Japan, Kazakhstan, Lesotho, Malaysia, Maldives, Mongolia, Myanmar, Uzbekistan, Pakistan, Philippines, Kyrgyzstan, the Dem. People’s Rep. of Korea, Sri Lanka, Thailand and Viet Nam.

300 MHz sub-band ↓ , with 31-31.3 GHz ground-to-HAPS .

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Footnote 5.543A … Systems using HAPS in the band 31-31.3 GHz shall not cause harmful interference to the radio astronomy service having a primary allocation in the band 31.3-31.8 GHz, taking into account the protection criterion as given in Recommendation ITU‑R RA.769. …

5.BC07 The power flux-density in the band 48.94-49.04 GHz produced by any geostationary space station in the fixed-satellite service (space-to-Earth) operating in the bands 48.2-48.54 GHz and 49.44-50.2 GHz shall not exceed –151.8 dB(W/m2) in any 500 kHz band at the site of any radio astronomy station.     (WRC‑03)

Current Protection

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1.11 to review sharing criteria and regulatory provisions for the protection of terrestrial services, in particular terrestrial television broadcasting services, in the band 620-790 MHz from BSS networks and systems, in accordance with Resolution 545 [COM4/5](WRC-03);

1.11 HEOs

Highly elliptical orbits (HEOs)

HEO constellation ground track

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WORKING DOCUMENT TOWARDS A PDNR ON PROTECTION OF THE RADIOASTRONOMY SERVICE FROM UNWANTED EMISSIONS OF HEO BSS SYSTEMS OPERATING IN THE BAND 620-790 MHZ [ANFR1]

TABLE 5 Maximum pfd levels per HEO BSS satellite to protect RAS

RAS band (MHz) pfd limit per satellite (dBW/m2)

Reference bandwidth (MHz)

608-614 (reference) -188.0 6

1 330-1 400 (spectral line) -198.7 0.02

1 400-1 427 (continuum) -183.7 27

1 400-1 427 (spectral line) -198.7 0.02

Epfd limits to protect RA bands at 610 MHz and 1400 MHz; pfd per satellite reduced by 74 dB from maximum radiated.

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1.11 HEOs 2% of sky blockage at zenith

Article 22.5C.1 Equivalent power flux density (epfd) is the sum of the pfds produced by a satellite system, taking into account the off-axis discrimination of a reference antenna.

Calculation of the effect of a HEO constellation, in terms of epfd. In some parts of the sky there is a high probability of interference.

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1.17 to consider the results of ITU-R studies of compatibility between the fixed satellite service and other services around 1.4 GHz, in accordance with Resolution 745[COM5/14](WRC-03);

further resolves to invite ITU-R, as a matter of urgency

3 to carry out studies, including the measurement of emissions from equipment that would be employed in operational systems, to validate that the systems meet all requirements for the protection of passive services in the band 1 400-1 427 MHz from unwanted emissions from FSS feeder links around 1.4 GHz for non‑GSO satellite systems in the MSS with service links operating below 1 GHz;

1.17 FSS Feeder Links near 1.4 GHz

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1.17 2% of sky blockage at horizon

WDTPDNR-1

pfd limit per satellite to protect RAS:90dB of rejection needed.

This time the interference is

near the horizon.

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WDTPDNR-2

Assuming an unwanted emission power limit of –60 dBW radiated in the band 1 400-1 427 MHz by MSS feeder link Earth stations operating in the band 1 390‑1 392 MHz, (imposed by the protection of the EESS), it is necessary to have a protection zone around each RAS station operating in this band of radius of about 30-50 km. Based on 98% propagation loss (blockage).

FSS Uplink 2% of blockage near horizon

2% + 2% + 2 % + … of passive band lost

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1.21 Band by band studies TG1/9

1.21 to consider the results of studies regarding compatibility between the radio astronomy service and the active space services in accordance with Resolution 740[COM4/17](WRC-03) in order to review and update, if appropriate, the Tables of threshold levels used for consultation that appear in the Annex to Resolution 739[COM4/15](WRC-03);

TG1/3, 1/5, 1/7, 1/9 (a long sad history)

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• Line of sight: can’t shield against them!

• Global coverage: all terrestrial sites affected

• Spread spectrum: radio pollution of passive bands

• Many satellite bands near radio astronomy bands

• Many examples (GLONASS, Astra, Tex, Iridium, … )

• Malfunctions are difficult to repair in space

• Long timescale for change, once launched

• More than 100 satellites launched per year

• No pre-launch check on total emissions

(environmental impact)

Satellite Interference to RA

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0.1 1 10 100 1 103

260

240

220

200

180

Frequency (GHz)

SP

FD

at

Gro

und

(dB

W/m

^2 H

z)Appendix 3 Spurious Emission Limits for

Satellites (TG1/5, WRC-00)

LEO

GSO

RA.769

For new satellites

from 2003 and all

satellites from 2012

After 6 years!

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resolves1 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 … if the unwanted emissions from the space station cannot meet the values given in the Annex …b) the concerned administrations enter into a consultation process in order to identify further steps with a view to achieving a mutually acceptable solution;

Res.739 (WRC-03) TG1/7

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Further band pairs are under study in TG1/9, for WRC-07.

But unwanted emission levels are not measured before launch anyway! What incentive to get it right?

In the event of interference the ITU-R recommends consultation. Will this help RA?

WP4A continues to be unhelpful, e.g. new PNDR Practical Levels of Unwanted Emissions.

However, when new satellite allocations are made, RA limits are accepted into the RR (via new Footnotes).

TG1/9 and WRC-07

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7.2 WRC-10 Agenda

2.2 to consider frequency allocations between 275 GHz and 3 000 GHz taking into account the result of ITU-R studies in accordance with Resolution 950 [COM7/1](WRC-03);

resolves 2 That administrations may submit for inclusion in the Master International Frequency Register details on systems which operate between 275 and 3 000 GHz …

Currently Footnote 5.565 identifies frequency bands within the range 275-1 000 GHz that are used by passive services for spectral line measurements.

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WRC-2000 Results

Success takes time and planning.

We need to start now, preparing our sub-mm case and agreeing our common position.

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2.7 to consider the progress of ITU-R studies concerning the technical and regulatory issues relative to the fixed service in the 81‑86 and 92-100 GHz frequency bands, taking into account Resolutions 731 (WRC‑2000) and 732 (WRC‑2000); (FS,MS,RA sharing)

RES731 to determine if and under what conditions sharing is possible between active and passive services in the bands above 71 GHzRES732 that appropriate measures should be taken to meet the spectrum requirements for active services for which the technology will be commercially available at a later time.

2.7 Review > 71GHz

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Radio-Quiet Reserves

ITU-R Working Party 7D, Draft New Question 2004 (answer by WRC-2010)

1. What are the characteristics of existing radio quiet zones?

2. What characteristics of the instruments of the Radio Astronomy Service have stimulated the development of radio quiet zones?

3. What characteristics of the electromagnetic environment stimulated the development of radio quiet zones?

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• Site control

• Jodrell Bank Consultation Zone

• Protection of particular frequency bands to agreed distances e.g. TV channel 38, 606-614 MHz

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ITU-R Radio Regulations:Passive frequency bands; protection from recognized radio transmitters; coordination procedures for transmitters in-band or in nearby bands.

Local and National Law:Radio-Quiet Zones governing any electrical interference, not just from radio transmitters. May be helpful against new technologies such as PLC.

Site Control:Self-protection from astronomers and modern electronics!

Layers of Protection

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Screened box for 2 Workstations

Computers Radiate in Passive Bands

Galaxy-like emissions recorded at ~10 Jy

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1956 West Virginia state law puts zoning restrictions on the use of electrical equipment within 10 miles of any radio astronomy facility.

1958 National Radio Quiet Zone established by FCC: 13,000 square miles of Virginia and West Virginia.

The laws were set up before the radio telescopes were built and before any frequency bands were allocated to the RAS.

1956 West Virginia state law puts zoning restrictions on the use of electrical equipment within 10 miles of any radio astronomy facility.

1958 National Radio Quiet Zone established by FCC: 13,000 square miles of Virginia and West Virginia.

The laws were set up before the radio telescopes were built and before any frequency bands were allocated to the RAS.

Greenbank Radio-Quiet ZoneGreenbank Radio-Quiet Zone

2929thth October 2004 October 2004 ESF Workshop, CagliariESF Workshop, Cagliari

Cerro-Chascón Science Preserve (ALMA)

Protected against mining etc. by Chilean Government Supreme Decree No. 185, June 1998

San Pedro2,500 m

ALMA 5,000 m

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ALMA Quiet ZoneExempt Resolution No. 1055, 17 August 2004.

Protection for primary allocated bands, via zones.

30-km radius Protection Zone: no transmitters in RA bands used by ALMA.

120-km Coordination Zone: transmitters in RA bands only by negotiation/coordination.

Limits to unwanted emissions based on Rec.RA.769-1.

Plus eirp limits on all transmitters in Coordination Zone operating below 31.3 GHz.

No protection from satellites or HAPS, or mobiles outside the Protection zone.

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Forte Satellite: Earth at 131 MHz

Radio-quiet zones (controlled emission zones) can provide extra protection for new mega-facilities such as SKA that will need to observe outside the allocated frequency bands. What about LOFAR?

?