Australian scientists unveil new military satellite dish – here’s how it works

A new type of military communications device was unveiled at the 15^th Australian Space Forum in Adelaide last week.

The device is called the Compact Hybrid Optical-RF User Segment (CHORUS) prototype terminal and the team hopes that it will create more stable and secure military satellite communication.

It looks a little like a satellite dish or a very small version of one of the ASKAP radio telescope antennas, but what makes it interesting is that it can receive both radio waves and optical – better known as laser – transmissions.  

The “best of both worlds” according to ANU Associate Professor Francis Bennet who worked on the CHORUS prototype.

“We’re using lasers to send information just like you would over a fibre optic cable under the sea except we don’t have a cable connecting the two ends. In the case of the CHORUS terminal, the aim is to be able to do laser communication between space and the ground station,” Bennet told Cosmos.

They’ve called this mix of a radio antenna and an optical telescope an ‘AntennaScope’.

Most communications just use radio waves, as these are easy to send and receive. However, radio signals spread as they move through the air, and so they can be easily intercepted. There’s also issues with running out of room in the radio spectrum with so many satellites in space.

Optical has its own problems though – for example if it’s a cloudy day or there’s turbulence in the atmosphere, the laser can’t get through – but having both options allows for redundancy.

“Radiofrequency can also have its own issues with the atmosphere, but they’re completely different to what you have with the optical, so in most scenarios when one doesn’t work, the other will,” says Bennet.

“If you’ve got good conditions for the optical system then you can push a lot of data through very quickly. But if that starts to degrade or your conditions aren’t perfect, you can fall back to the radio frequency system and still get some connectivity.”

Bennet explains that the system could also be used for quantum communication in the future, which would provide additional protection from being hacked.

“You can start to introduce basically unhackable signals using quantum communication techniques between different users,” he says.

“That’s something that you can’t do with all the other technology that we have today.”

Of course, the terminal is only one half of the puzzle, and when the system was undertaking testing, researchers at the Defence Science and Technology Group had to create their own ‘pseudo-satellite’ to prove the hybrid system worked as designed.

“CHORUS has the potential to position Australia as a leader in developing and delivering an entirely new class of military satellite communications service for the Australian Defence Force and its allies,” says Professor Andy Koronios, the CEO of SmartSat CRC.

“This includes developing optical communications to provide higher bandwidth, lower observability, and more secure communications than current RF-only technologies for tactical communications between maritime, aircraft, and land vehicles. We believe this technology has additional commercial applications, such as commercial shipping and cruise liners.”