Changes to Differential GPS | ACMA

Changes to Differential GPS

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Do you use Differential GPS (DGPS) equipment in the 400 MHz band? There are some changes that you need to know about.

We’ve reviewed the 400 MHz band and made some big changes to support new technologies, reduce congestion and provide spectrum exclusively for government use. Significant changes include the frequencies DGPS equipment can operate on, and the allowable operating bandwidths.

What are the new arrangements?

Under the new arrangements, several segments between 403 and 470 MHz have been identified for the harmonised government spectrum (HGS). HGS will be primarily used by state and territory governments for law enforcement, emergency services and public safety communications. Some segments in HGS were previously used by DGPS services, in particular Segment T (457.50625–459.9875 MHz) and Segment Y (467.50625–469.9875 MHz).

Through our field spectrum monitoring activities, we‘ve found a number of unlicensed DGPS services operating in Segment Y. As government services transition into the HGS, there is a risk that unlicensed DGPS equipment could interfere with these critical communications.

All non-government users operating DGPS equipment licensed to operate in a high- or medium-density area were required to transition out of the HGS by 31 December 2015. All non-government users operating DGPS equipment in low- or remote-density areas have until 31 December 2018 to relocate. To view these areas, see the apparatus licence fee density maps.

Find out more information about licensing requirements for DGPS operation.

A number of other changes occurred as a result of the 400 MHz band review, in particular the transition to narrowband services (12.5 kHz or 6.25 kHz). We have developed an online tool, which lists the transition requirements for current licences and the relevant details.

What do you need to do?

  • Ask the supplier of your DGPS equipment whether all of your frequencies are still licensed. Alternatively, check the frequencies yourself using our online tool. The guide on 400 MHz changes provides some useful tips on how to search this tool and information on the density areas. 
  • If you don’t hold an apparatus licence for a frequency programmed in your equipment, you should remove it immediately unless you have the written authorisation from a current apparatus licensee to use that frequency under a third-party arrangement. It is against the law to operate an unlicensed radiocommunications device. 
  • If you hold an apparatus licence for the frequency programmed into your DGPS equipment or are operating under a third-party arrangement, make sure you understand the conditions of the licence and any transition requirements you must meet. The 400 MHz implementation FAQ provides useful information on how to vary or surrender a licence.

What are the consequences?

Under the Radiocommunications Act 1992, it is an offence to operate a radiocommunications device other than as authorised by an apparatus, class or spectrum licence. We take a graduated approach to investigating unlicensed operations and generally seek compliance through education or infringement notices. However, if the case warrants a stronger response, the ACMA can prepare a brief of evidence for the Commonwealth Director of Public Prosecutions to enable criminal proceedings. A court can impose penalties for unlicensed operation of up to two years’ imprisonment for individuals and body corporates may receive a penalty of over $300,000 (1,500 penalty units). Other offences and penalties may apply depending on the non-compliant behaviour.

Compliance in the HGS is a priority compliance area for the ACMA during 2016–17.

Need more information?

  • Read more about licensing requirements for DGPS operation.
  • Visit the 400 MHz hub for information on the 400 MHz band review.
  • If you can’t find the information you need on these webpages or documents, please call the ACMA’s Customer Service Centre on 1300 850 115 or email Alternatively, you can contact an accredited person.

See the checklist below to make sure you're operating correctly.

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Download a printable version of the checklist (PDF).

Last updated: 10 February 2019