China’s hypersonic weapons can be guided by the stars if GPS fails: report

China's hypersonic weapons can now utilize the stars for navigation when systems like GPS or BeiDou are compromised, according to a project led by the Guangdong Aerospace Research Academy. The research, which concluded with final expert review on Monday, aimed to create a star-based navigation system capable of operating at hypersonic speeds (Mach 5 and above).

Hypersonic weapons pose a significant strategic advantage due to their difficulty in interception, but they require highly autonomous and precise navigation systems. Traditional celestial navigation, like that used by sailors in the past, involves observing stars to determine position and motion. Modern electronic systems perform a similar function by tracking star movements.

This technique, known as celestial navigation, offers a self-contained and interference-immune alternative to systems relying on ground stations or satellites. While the concept is straightforward, implementing it at hypersonic speeds presents challenges. Intense friction with the atmosphere at such speeds generates a shock layer and plasma sheath that can reach over a thousand degrees Celsius, bending starlight and emitting strong infrared radiation, which can drown out fainter starlight.

Researchers at the Guangdong Aerospace Research Academy addressed these issues by developing databases and algorithms to predict how starlight would be affected by the vehicle's aerodynamic environment. They created a "complete technical chain," from fundamental research to prototype development, tailored for high-speed flight applications.

The team compiled two key databases: one on the thermal-chemical radiation of hot air and another on thermally induced radiation interference. They also developed simulation software to predict how starlight would be bent and how to mitigate radiation interference, achieving a spectral resolution of 0.12 nanometres and controlling radiation simulation error to within 18.9%.

The star sensor prototype demonstrated high recognition rates, exceeding 99% in interference-free conditions and maintaining over 80% recognition even under strong aerodynamic radiation interference. The technology's accuracy in attitude measurement was better than 5 arcseconds. Beyond its military applications, the report highlighted potential commercial uses, with the radiation measurement and simulation technologies already generating significant revenue for aerospace institutes.

The report also noted that the technology can provide real-time data on combustion chamber conditions, aiding in industrial chain upgrades and high-end inspections in various industries.