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Australia-US defence trials point to more reliable GPS navigation

The GPS navigation system might become more reliable and useful to the Australian Defence Force in military conflict, as a result of trials Australian and US defence scientists conducted at Woomera earlier this year.

GPS Jammer Locator trials at Woomera.

More than 30 US and Australian military and civilian personnel were involved in a ten-day trial in mid-north South Australia in March, which demonstrated that the vulnerability of Global Positioning System (GPS) receivers to interference can be greatly reduced.

The GPS Jammer Locator (JLOC) trials were a joint demonstration between the United States Air Force Operational Test and Evaluation Centre (AFOTEC), and Australia's Aircraft Research and Development Unit (ARDU) the Defence Science and Technology Organisation at Salisbury, SA, and Air Services Australia (ASA)

The JLOC system, under development through a US Air Force Research Laboratory (AFRL) contract to the American company NAVSYS, is designed to locate GPS jamming/interference sources and provide data to tactical/strategic planners to assist in defeating these sources.

DSTO's Dr Anthony Finn (former GPS head with DSTO) says the trials were the first held under a bi-lateral agreement between Australia and the US to progress GPS protection research.

"GPS is the world's primary means of precise navigation and timing information. It is used in a very wide range of applications that include air, sea and land navigation, intelligent transportation systems, mining, and agriculture, as well as in telephone and electrical power grid synchronisation.

"Its smooth operation is now critical. Unfortunately, it is highly susceptible to both electromagnetic interference and environmental phenomena, which can seriously impair its performance for both military and civilian operations," says Dr Finn.

"GPS receivers can be rendered ineffective with simple, inexpensive, pocket-sized 'jammers' deliberately designed for the purpose, or coincidentally by TV antennas, radars, and communications towers.

"It is therefore crucial that we seek out techniques to counteract intentional and unintentional interference to GPS.

"The aim of the trials at Woomera was to show that it is possible to locate and identify GPS interferers.

"The JLOC system was used to locate ground based GPS interferers provided by the DSTO from a combination of ground and airborne platforms.

"This was achieved successfully and repeatedly and means that in the future GPS users will be able to identify and avoid or deal with GPS interferers.

"A number of methods were also employed to reduce receiver vulnerability and these protection systems clearly showed that the vulnerability of GPS receivers to interference can be greatly reduced."

Dr Finn adds that the trials were a success on several levels.

"Following the success of these trials, a number of further international activities are planned for Woomera. It is becoming prohibitively expensive for the Americans to mount trials of this scale in the US because of the impact they would have on the civilian infrastructure that is dependent upon GPS - there are simply no empty tracts of land large enough to support such an exercise.

"At Woomera we had an area of up to 450 kilometres radius at our disposal which is relatively free from other GPS users, enjoys clear weather and has good airfield and support facilities allowing several aircraft the freedom to fly around the Woomera region locating multiple interferers on the ground.

"The experiment was also a turning point in DSTO's involvement in GPS research with the Americans because we were able to demonstrate our knowledge and expertise in this area and contribute high quality interference equipment to the trials," says Dr Finn.

"This relationship with the United States (which owns and operates the GPS) is vitally important to Australia because it provides us access to information that we would not otherwise be privy to."

Australian participants in the trials at Woomera included the Department of Defence, DSTO, CSSIP, Air Services Australia, and the Aircraft Research and Development Unit. The US personnel represented the Air Force Space Battlelab, the Air Force Operational Test and Evaluation Centre, the GPS Joint Program Office, the Air Force Research Lab and the NAVSYS company.

Dr Chris Baker is the current GPS head for DSTO Salisbury.

Manager, Defence Science Communications (Edinburgh)

Mr Steve Butler
Defence Science Communications

DSTO Edinburgh
PO BOX 1500
Edinburgh
South Australia 5111

Phone:

(08) 8259 6923

Fax:

08 8259 6191

Email:

stephen.butler@dsto.defence.gov.au

The Defence Science and Technology Organisation (DSTO) is part of Australia's Department of Defence. DSTO's role is to ensure the expert, impartial and innovative application of science and technology to the defence of Australia and its national interests.

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