Australasian Science: Australia's authority on science since 1938

FM Radio Radar Reveals Defence Threats in Space

Astronomers at the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) have teamed up with Adelaide company Silentium Defence to develop a passive radar for the surveillance of objects in space.

The partnership, which was awarded funding from the Federal government’s Defence Innovation Hub, will use the Murchison Widefield Array (MWA) radio telescope to record radio waves bouncing off objects in Earth’s orbit. These objects can be 1000 km away and travelling at up to 8 km/s. The signals recorded by the telescope are then processed to create a passive radar. The technique is passive because the radio waves are generated by FM radio stations located around Australia, not from a radar transmitter.

Prof Steven Tingay explained that FM radio station broadcasts are carried into space and bounce off objects in orbit around the Earth. “We can use the radio waves during both day and night, and when it is cloudy, so it can provide 24/7 surveillance in a way that other systems based on optical telescopes cannot,” Tingay explained.

Surveillance is important to monitor valuable and strategic assets in space, and to evaluate the risk of collisions that could destroy satellites critical for communications.

The MWA radio telescope is a precursor to the $1 billion Square Kilometre Array, and is located in the Murchison region of Western Australia.