Jepang menggunakan gelombang suara untuk mendeteksi dan memantau kapal selam Cina

Government sources have revealed that the submarine detected plying the waters of the contiguous zone around Minami-Daitojima island in Okinawa Prefecture on Sunday were picked up by a Maritime Self-Defense Force (MSDF) patrol plane using a sonobuoy – a small floating sonar system that emits sound waves, and transmits its data back to the sonar operators. Using the sonobuoy, the plane was able to let the submarine know that it was being monitored.

In light of three confirmed incidents of submarines navigating underwater in the same area this month, the MSDF has been using what is called “active pings” from sonobuoys – a sonobuoy usually does not emit sound waves to avoid detection by submarines – where sonar operators intentionally have the sonobuoy emit sound waves audible to the target submarine as a sign that it was in fact being monitored by the Japanese. This tactic is being used as a warning to China, because the submarine incidents have been increasing in the past month, as well as repeated appearances by Chinese naval vessels in the waters around the disputed Senkaku/Diaoyu islands. The Japanese central government has promised that it will be beefing up surveillance and security activities on Chinese ships, the same government sources revealed.

Initially, Japan’s Defense Minister Itsunori Onodera said in a statement that while the SDF has identified the nationality of the submarine vessels, that they will not be disclosing the identity. The Japanese government eventually decided to reveal the information after a meeting Japanese Prime Minister Shinzo Abe and Onodera. “We gave China a signal that Japan is well aware of the moves of Chinese submarines and to pressure Beijing to restrain itself,” Onodera said.