The Australian Radio Quiet Zone WA (ARQZWA)

View over the Murchison Radio-astronomy Observatory in Western Australia. Credit: Ant Schinckel, CSIRO.

The Australian Radio Quiet Zone WA (ARQZWA) is centred on the Murchison Radio-astronomy Observatory (MRO). CSIRO, as the MRO entity, manages the MRO, which is the home to CSIRO's ASKAP telescope and the international MWA project, and the future site of Australian infrastructure for the international Square Kilometre Array (SKA) project.

CSIRO’s role encompasses a broad range of duties, described in further detail below.

 

Australian Radio Quiet Zone WA (ARQZWA)

The Australian Radio Quiet Zone WA (ARQZWA), originally called the Mid West Radio Quiet Zone, was established by the Australian and Western Australian Governments to protect radio astronomy receivers from harmful interference, while allowing for opportunities for coexistence with other activities.

The Radio Quiet Zone, centred on the Murchison Radio-astronomy Observatory (MRO), comprises:

  • A 70km radius Inner Zone; other radiocommunications services within the Inner Zone are taken to be secondary services in relation to radio astronomy; and
  • An Outer Zone from a 70km to 150km radius; and
  • Coordination zones from 70km up to 260km radius (depending on frequency).

The 2011 Memorandum of Understanding on Radio Quiet Matters (MoU) between the Australian and Western Australian Governments outlines the objectives, principles and processes to protect the radio quiet nature of the MRO and facilitate co-existence between radio astronomy and industry.

These principles are consistent with the legislative, regulatory and policy instruments put in place by the Australian Communications and Media Authority (ACMA), including the Radiocommunications (Mid West Radio Quiet Zone) Frequency Band Plan 2011 (the Band Plan), RALI MS 32, as well as the Radio Telescope Mineral Resource Management Area and Section 19 zones under the WA Mining Act 1978, administered by the WA Government Department of Mines and Petroleum.

Under the Band Plan and RALI MS32, a potential applicant for a radiocommunication transmitter must consult with the MRO Entity. The intention is to ensure that radio astronomy receivers are protected from harmful interference, while maximising the opportunities for other spectrum users to use the spectrum.

If interference from a proposed transmitter would exceed specified threshold levels, the licence applicant must undertake interference mitigation measures as described in RALI MS32, including those that would reduce the signal levels to below the thresholds.

Further to the ACMA regulations, mining exploration within the 70km radius Inner Zone of the ARQZWA must be conducted according to a Radio Emissions Management Plan (REMP) that demonstrates the proposed operation will be consistent with radio astronomy requirements. The REMP may cover radiocommunication transmitters (which are subject to the ACMA regulations) as well as incidental emissions from electrical machinery or vehicles.

Decisions on whether to approve the program of work described in REMPs are made by the Western Australian Department of Mines and Petroleum (DMP).

Outside the 70km radius Inner Zone, within the framework of any applicable legislation or regulation, the Governments have committed to a principle of coexistence:

  • Industry in this region is required to consult with the MRO Entity with a goal of developing and implementing technical solutions that minimise the radiofrequency impact of their operation on the radio astronomy operations.
  • In return, the MRO Entity will be required to facilitate practical and cost-effective solutions in a timely manner that maximise opportunity for shared use of spectrum within acceptable limits, as outlined in the Management Framework.

CSIRO responsibilities in the RQZ

CSIRO is the manager of the Murchison Radio-astronomy Observatory (MRO), known as the MRO Entity1. The MRO Entity role encompasses a broad range of duties including management of land, infrastructure and telescopes, described in further detail below.

The role includes assessing and advising on radio frequency interference levels2 from proposed activities and, when required, it also includes facilitating co-existence solutions with other spectrum users.

Assessing and advising on radio frequency interference

As the MRO Entity, CSIRO assesses a proponent’s proposal for a radiocommunications transmitter and informs the ACMA, on behalf of the MRO’s radio astronomy scientists and other stakeholders, on the impact of the proposed transmitter on radio astronomy science. This includes an estimate of the likely interference level at the telescope facilities from a proposed radio frequency (RF) transmission, and an evaluation of the sensitivity of radio astronomy observing programs to the radio-frequency interference.

As the MRO Entity, CSIRO also provides information to the DMP on the interference impact of proposed mining and exploration activities within the Radio Telescope Mineral Resource Management Area, encompassing both licensed transmissions (which must also comply with the ACMA regulation) and broadband emissions from electrical equipment, as documented in the REMPs.

Facilitating coexistence

CSIRO is committed to continuing to act, as it has been doing, in accordance with the co-existence principles of the MOU.

In particular, in relation to the Outer Zone of the Band Plan and the coordination zones of RALI MS32, CSIRO is committed to continuing its current work to facilitate practical and cost-effective solutions with industry in a timely manner that maximise opportunity for shared use of spectrum within acceptable limits, based on its technical expertise and experience in spectrum management.

Where it has been possible to do so, CSIRO’s work to facilitate solutions has involved providing practical advice and guidance to the industry proponent to reduce the impact on radio astronomy. This has been successfully achieved through a number of activities, including, as appropriate:

  • meeting and communicating with system designers employed by the industry proponent;
  • undertaking analysis and modelling of radio frequency interference of initial proposals and, as required, of modified proposals incorporating mitigation techniques;
  • helping to specify criteria for interference mitigation techniques;
  • suggesting preliminary interference mitigation techniques for radiocommunication system designers to further explore, such as alternative placement of transmitter towers, changing frequencies, reducing power levels or shielding equipment;
  • assessing the expected impact of proposed interference mitigation techniques; and
  • engaging in collaborative technical work, within its area of expertise, to explore possible solutions.

Under ACMA measures

It is the industry proponent that has ultimate responsibility for the development and implementation of the required amendments to its proposed transmitter, including undertaking any design work to reduce interference.

CSIRO encourages industry to provide information on its proposed radiocommunication systems to enable CSIRO to consider possible technical solutions for investigation. However industry is not obliged to accept CSIRO’s input and can seek advice elsewhere.

The licence proponent makes any decisions regarding what solutions it is prepared to investigate and/or implement, and makes any decisions regarding what to include in a licence application to the ACMA. If it is not possible to reduce the transmitted interference to acceptable levels, CSIRO can investigate whether operational considerations could reduce the scientific impact of the proposed transmission, such as operating the devices at certain times.

The ACMA considers licence applications and makes the final decision regarding interference disputes in accordance with its regulatory role and cannot be bound by the advice of the proponents or the MRO entity.

Under the Radio Telescope Mineral Resource Management Area

Similarly, CSIRO provides advice on the interference potential of incidental emissions described in a REMP and, where possible, suggests modifications to reduce the interference to acceptable levels.

It is the industry proponent that has the ultimate responsibility for developing and implementing any solutions and preparing an REMP. DMP considers the REMP and makes the final decision on whether a program of work can proceed.

 

Further Information

 

Footnotes
[1] Further to its role as the MRO Entity, CSIRO owns and operates the Australian SKA Pathfinder and is a partner in the Murchison Widefield Array radio telescope project, both of which are located on the MRO.
[2] Further to its role as the MRO Entity, CSIRO sometimes provides broader advice to the ACMA on general areas of spectrum management based on its technical expertise and experience in this area.

 

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