CSIRO researchers have developed two field-ready Quantum Light Sources for a Defence Science and Technology Group-led (DSTG) project focused on secure timing in GPS-GNSS degraded or denied environments. Practically, the Quantum Light Sources are quantum-enabled timing devices.
“This work is a significant milestone in the development of quantum-secure time transfer in Australia," CSIRO Technical Lead, Matt Broome, stated.
“With this work, CSIRO has developed specialised capability, which puts Australia on the path to a more resilient future in global positioning technology.”
Global Navigation Satellite Systems (GNSS) are satellites which carry atomic clocks that transmit time-stamped signals to receivers on Earth. The Global Positioning System (GPS) is the best-known GNSS in Australia and the United States, but it is only one of several systems used globally.
Precise timing required from GNSS and GPS underpin defence communications, navigation and coordination, as well as civilian systems including power grids, finance, transport and emergency services. However, jamming and spoofing are making reliance on conventional satellite timing increasingly contested.
The CSIRO-developed sources generate entangled photons for ground-to-satellite time transfer. This enables a timing signal that is highly sensitive to interference, meaning attempted tampering can be detected and users can move to another channel.
CSIRO is working with the DSTG and local and international university partners on quantum technologies that enable critical systems to continue to operate when GPS signals are degraded or denied.
Jamming and spoofing are two ways GNSS signals can be disrupted. Jamming blocks weak satellite signals so they cannot be received, while spoofing is more sophisticated, sending a false but convincing signal that tricks a receiver into accepting the wrong location or time.
Both are of increasing concern because GNSS signals are weak and therefore more susceptible to interference by the time they reach Earth.
Though they are illegal in Australia and many other countries, jamming devices are still accessed through illicit channels. Sophisticated spoofing capability is generally harder to obtain and use effectively, but the risk is growing as software-defined radio, open-source tools and technical know-how become more accessible.
GNSS interference is no longer a remote or theoretical risk – it is occurring globally. In contested environments, GNSS signals are being disrupted as an act of war, causing vital systems to fail. The result can be catastrophic when operations taking place across air, land, sea, cyber and space lose communication.
The problem is being tackled through the DSTG-led quantum project designed to enhance secure timing technologies for the Australian Defence Force (ADF).
The CSIRO Quantum Light Source generates tiny particles of light that are linked through the laws of quantum physics. Initially collaborating with Heriot Watt University, the CSIRO team set out to bring their Scottish counterparts’ source design thinking out of the lab and into the field.
The capability emits entangled photons that can maintain quantum correlations over vast distances, CSIRO claims. Called quantum entanglement, two tiny photon particles become linked so closely that a change to one is instantly reflected in the other, even when they are far apart.
While one photon stays on Earth its entangled partner is sent to an orbiting satellite hundreds of kilometres away. Despite the distances involved, the photons remain quantum entangled and a secure communication link can be established.
Quantum entanglement is particularly useful for ground-to-satellite time transfer because it is extremely sensitive to interference. So, if someone were to intercept or tamper with the signal, the quantum state changes and the disruption can be detected instantly – enabling the user to switch to a different channel, CSIRO explained.
Known as entanglement distribution, this process can be done continuously to ensure a secure link and is what makes CSIRO’s Quantum Light Source spoofing-proof.