GPS alternative for drones uses visual data from stars

Remote sensing engineers from the University of South Australia (UniSA) have combined celestial navigation with vision-based technology to provide an alternative means of night-time navigation for drones, to be used in environments where GPS is unavailable or unreliable. The system in question relies on an algorithm that uses visual data from stars and processes it through standard autopilot systems.

“[You’re] given an image captured from an aircraft, and within that image are a number of stars,” explained UniSA researcher Dr Samuel Teague. “If we’re able to identify those stars and compare them against a database, given that we know the orientation that the camera was facing and the point in time at which that image was taken, we can actually infer the location of the aircraft from that data.”

Testing on a fixed-wing drone demonstrated accurate positioning within 4 km — billed as a remarkable achievement given the system’s simplicity and cost. Teague added that lightweight, affordable celestial navigation system can be integrated into standard drones, offering a dependable backup.

“Unlike traditional star-based navigation systems, which are often complex, heavy and costly, our system is simpler, lighter and does not need stabilisation hardware, making it suitable for smaller drones,” he said.

“This type of navigation is ideal for operations over oceans, or in warfare zones where GPS jamming is a risk.”

Key advantages of the technology include the following:

• Non-emissive navigation: Since the system uses passive celestial cues, it doesn’t emit signals, making it difficult to detect.
• Low cost and lightweight: Built with commercially available components, the system is significantly lighter and more affordable than traditional celestial navigation equipment.
• Robustness against GPS jamming: By relying on passive celestial navigation rather than radio frequency GNSS signals, the system provides a reliable alternative for drones operating in GPS-denied environments.
   

Senior researcher Professor Javaan Chahl, DST Joint Chair of Sensor Systems in UniSA’s STEM unit, said the technology could enhance the operational capabilities of uncrewed aerial vehicles (UAVs) across many industries.

“For instance, in environmental monitoring over remote locations or long-endurance surveillance missions where GPS might be unavailable or compromised, this technology offers a valuable new capability,” he said.

“GNSS denial is an increasing challenge, and our research addresses this gap. We have developed a navigation method that’s resilient, independent of external signals, and achievable with low-cost, easily accessible components. This makes it applicable to a variety of UAVs, from commercial drones to more advanced defence applications.”

The project is part of UniSA’s research and development program into key drone technologies for defence and civilian applications. It has been described in the journal Drones.

Image credit: iStock.com/viti