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Overbom

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Chinese scientists develop long-distance underwater communication in South China Sea​

  • Researchers say innovation would allow submarines and drones to maintain contact over more than 30,000 sq km (11,600 square miles) and aid communication with smart weapons
  • Team is developing a new technology to convert sound signals into whalesong to camouflage military channels
A listening device picked up sound signals from 105km (65 miles) away at a depth of 200 metres (656 feet) during a field test in an important passageway for submarines, according to the study by the team at northwestern China.
The data transmission rate reached nearly 200 bits per second (bps), on par with the bandwidth of very low-frequency radio sent by a naval command to nuclear submarines using the world’s largest land-based antennas.
Despite heavy noises in the background, the encrypted messages contained no mistakes, the researchers said.
Using commercially available technology, acoustic communication of this speed and quality is usually restricted to a distance of less than 10km.
In an experiment conducted by South Korean researchers last year using British hydrophones, for instance, a transmission rate of 128bps was recorded over a distance of 20km


The results of the South China Sea experiment proved the “effectiveness and good performance” of the new technology in increasing underwater communication range and efficiency, said project lead scientist professor Liu Songzuo, of Harbin Engineering University, one of the Chinese universities sanctioned by the US government, in a paper published in the domestic peer-reviewed journal Acta Acustica on September 6.
Liu and his colleagues conducted the experiment over a 3,800-metre deep sea floor located between the Taiwan-controlled Dongsha Islands, known in Taiwan as Pratas, and the hotly disputed Paracel Islands, known in mainland China as Xisha. Some military experts said the area had been an important passage for submarines in and out of waters close to China.


Liu said they conducted the test on a windy day, with waves rocking the research ship while a strong sea current pulled the hydrophone array away from the best listening position. Under the water lay rough terrain with cliffs and gorges that could absorb, deflect and distort the sound waves.
The strength of signals picked up by the few sensors was only a few decibels, or quieter than a breath. And these signals were mostly drowned out against strong background noise caused by natural and human-man activities in the ocean, they said.
Liu’s team said it had developed a new communication protocol to overcome these challenges.
The technology, inspired by mobile phone communications, could package the signal into many separate but related segments and beam them out as sound waves in all directions.
The receiver could pick up some of these waves coming from different directions and at different times.
An algorithm helped the receiver identify each of these waves and reconstruct the full message using random bits of the collected information.
The mathematical model used in this study was developed and evaluated with real-life data collected from the South China Sea to improve its performance in the region.
In a conference presentation earlier this year, Liu’s team said they were developing a new technology to convert the sound signals into whalesong to camouflage military channels.
 

luosifen

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zhangxueyan1.jpgAn air-cushioned landing craft attached to a naval landing ship flotilla under the PLA Southern Theater Command maneuvers at high speed during a beach landing training exercise in mid-August, 2022. (eng.chinamil.com.cn/Photo by Zhang Xueyan)

zhangxueyan2.jpgAn air-cushioned landing craft attached to a naval landing ship flotilla under the PLA Southern Theater Command arrives on shore during a beach landing training exercise in mid-August, 2022. (eng.chinamil.com.cn/Photo by Zhang Xueyan)

zhangxueyan3.jpgAn armored vehicle rolls out of an air cushioned landing craft during a beach landing training exercise conducted by a naval landing ship flotilla under the PLA Southern Theater Command in mid-August, 2022. (eng.chinamil.com.cn/Photo by Zhang Xueyan)
 

by78

Lieutenant General
A towed target barge.

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luosifen

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42nd Chinese naval escort taskforce sets off for Gulf of Aden escort mission​

mayubin1.JPGSailors assigned to the 42nd Chinese naval escort taskforce wave goodbye to their comrade-in-arms and set off for escort missions in the Gulf of Aden and the waters off Somalia, after a farewell ceremony held at a military port in Qingdao, east China's Shandong Province on September 21, 2022. (Photo by Ma Yubin)

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Naval servicemen assigned to the PLA Northern Theater Command wave goodbye to the crew on the comprehensive supply ship Kekexilihu (Hull No. 968) of the 42nd Chinese naval escort taskforce at a military port in Qingdao, east China's Shandong Province on September 21, 2022. (Photo by Liu Zaiyao)

mayubin2.JPGGuided-missile destroyer Huainan (Hull No. 123) attached to the navy under the PLA Northern Theater Command berths at a military port in Qingdao, east China's Shandong Province on September 21, 2022. The 42nd Chinese naval escort taskforce composed of the guided-missile destroyer Huainan, the guided-missile frigate Rizhao and the supply ship Kekexilihu sets sail from Qingdao for escort missions in the Gulf of Aden and the waters off Somalia on September 21, 2022. (Photo by Ma Yubin)

liuzaiyao2.JPGSpecial operations soldiers assigned to the 42nd Chinese naval escort taskforce line up on the deck of the guided missile frigate Rizhao (Hull No. 598) at a military port in Qingdao, east China's Shandong Province on September 21, 2022. The 42nd Chinese naval escort taskforce composed of the guided-missile destroyer Huainan, the guided-missile frigate Rizhao and the supply ship Kekexilihu sets sail from Qingdao for escort missions in the Gulf of Aden and the waters off Somalia on September 21, 2022. (Photo by Liu Zaiyao)
 

by78

Lieutenant General
The construction of the large dry dock at the Yulin Naval Base in Hainan is progressing well. Aircraft carriers based there will no longer have to sail to Shanghai or Dalian for maintenance.

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Another satellite update. The dockside surfaces have been paved, and two cranes have been installed. The smaller dry dock to the side is for maintaining destroyers, frigates, and other smaller ships.

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Chilled_k6

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Radar troops on Mischief Reef detects an unknown speed boat attempting infiltration. The naval garrison responded promptly and drove away the speed boat.

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Article talks about American special ops stealth speed boats, which is probably the most likely culprit. Should be noted Antonio Bautista air base in the Philippines is only just over 200km from Mischief.
 

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