The Guardian • Issue #2071



Hannah Middleton

I recently saw a commercial TV promotion showing a a nuclear-powered submarine and a reporter saying it is invisible. This is rubbish.

Since its surprise announcement last year, there have been claims that the AUKUS submarines will be obsolete by the time they arrive in about 30 years time.

New technologies will by then mean the submarines will be both detectable and targetable. The Labor government is wasting at least $368 billion on weapons with built-in redundancy.

This criticism is confirmed by recent reports that Chinese scientists have reportedly developed a terahertz-based submarine detection device that detects tiny vibrations or ripples on the water surface caused by a submarine under the ocean.

According to the South China Morning Post, a National University of Defence Technology team tested the device that generates terahertz emissions/waves. These detected surface vibrations/ripples as small as 10 nanometers tall.

This small dimension is ‘well below the detection range of existing technology,’ according to a report on their work in the Journal of Radars, a Chinese-language peer-reviewed journal.

A small unmanned aerial vehicle platform has the advantage of good mobility, low cost, and flexible deployment, and could work together with other submarine detection methods such as a magnetic anomaly detector, microwave radar, or laser.

‘As a supplement to existing detection methods, it can provide important information for the detection and identification of submarines.

‘The experiment was conducted at an unspecified location in the northeastern city of Dalian in the Yellow Sea. The weather was fair at the time of the test, but breaking waves produced lots of bubbles.

‘The military scientists used an artificial sound source to simulate the noise emitted by a submarine. To replicate drone flight, the submarine detector was carried by an extended arm of a research ship,’ the SCMP report adds.

The university team found a problem with the surface disturbance caused by the underwater movement of a submarine. ‘The disturbance is feeble by the time it reaches the surface. Separating it from the natural waves of the ocean was previously thought impossible.’

However, the new device has hardware and software to address the issue. While the terahertz waves made the sensor extremely sensitive to even small surface water ripples, it was aided by a one-of-a-kind algorithm to ‘effectively identify nanometre-sized ripples over the wobbling ocean.’

In the test, the terahertz sensor picked up man-made ripples with amplitude ranging from 10 to 100 nanometres, depending on the sea conditions. The technology could also be used for ‘cross-medium’ communication between a submarine and overhead-friendly aircraft, which has been challenging even for advanced navies like the US.

The technology is at a preliminary level. ‘It practically needs to be seen, especially when scaling up production during mass manufacture. Advanced machines need specialised electrical and electronic components, which private companies do not commonly manufacture,’ the National University of Defence Technology team points out.

“Terahertz wavelengths are between the infrared and microwave spectrums, and systems operating on this foundation need an entirely different set of sensors and electrical circuitry,

‘Another thing is getting companies to design such components and sub-components as per specifications and then promising them bulk orders, guaranteeing profits and economies of scale.

‘Private firms usually do not invest in factory lines of specialised devices against piecemeal orders. It sometimes takes months and even several years coordinating with vendors to get the supply chain and manufacturing ecosystem right.’

The development follows previous reports of China’s success in 6G communication. Tianjin University’s School of Precision Instruments and Optoelectronics Engineering invented a laser system that can emit a continuous beam of electromagnetic waves in the terahertz spectrum, needed for 6G next-generation technology which promises exceptionally high-speed data rates and communications.

This was preceded by the breakthrough in 6G technology in January 2022, where researchers achieved a record transmission speed of 206.25 gigabits per second.

The Guardian can also be viewed/downloaded in PDF format. View More