Space scientists from China have revealed a breakthrough in magnetic detection technology that could boost the country’s underwater warfare capabilities.
During offshore trials, their drone-mounted quantum sensor system displayed picotesla precision in tracking magnetic anomalies.
It also mapped the seabed with extreme precision, the researchers explained in a new peer-reviewed paper. Their new system could detect enemy submarines with extreme precision, while also enabling a host of other applications.
China’s CPT submarine detector
Traditionally, anti-submarine forces have used optically pumped magnetometers (OPMs) to detect vessels. However, according to a South China Morning Post (SCMP) report, these have critical “blind zones” in low-latitude regions like the South China Sea. This is because the Earth’s magnetic field runs almost parallel to the surface. If the sensor’s optical axis aligns too closely with magnetic field lines, this weakens the signal.
China’s quantum sensor could overcome these limitations, giving China the edge when it comes to underwater warfare. Anti-submarine forces using the system could pinpoint a submarine with great precision and even detect the tail waves of enemy vessels.
The system, called the Coherent Population Trapping (CPT) atomic magnetometer, leverages quantum interference effects in rubidium atoms. According to the SCMP post, it exploits Zeeman splitting, which refers to shifts in energy levels caused by magnetic fields. This generates seven microwave resonance signals.
These frequencies are not weakened by alignment with the Earth’s magnetic field lines, the researchers explained in their paper published in the Chinese Journal of Scientific Instrument.
Extreme precision during trials
The new CPT system is reportedly on par with Canada’s MAD-XR system. MAD-XR is widely used by NATO forces. However, the team behind the new CPT advance claims their system is much more affordable.
“The MAD-XR is too sophisticated and expensive, limiting the scope of practical applications in real life,” the team, led by Wang Xuefeng, researcher with the Quantum Engineering Research Centre, China Aerospace Science and Technology Corporation (CASC), explained.
During trials, off the coast of Weihai, Shandong province, the CPT sensor was tethered to a drone using a 20-metre (65.6ft) cable. This minimised electromagnetic interference from the aircraft.
After the drone surveyed a 1,312 by 984 feet (400 by 300 meter) grid, raw data showed 2.517 nanotesla (not) accuracy. This was refined to 0.849 nT after error correction.
The researchers say their new system will have capabilities beyond submarine detection. This sensitivity would allow the system to map submerged archaeological sites, tectonic plates, and oil reservoirs.
