MH370 submarine Tracking: What technical means are available?

The MH370 's search and rescue came to the most hopeful and difficult stage. The focus of search and rescue in the Indian Ocean has shifted from the wreckage to the black box from April 5, when China first discovered the pulse signal. On the noon of 11th, Australian Prime Minister Abbott announced that he had been able to lock the black box of the Qantas airliner into a few kilometres. Although the location of the black box was not clearly stated, he said the searchers were confident that the signals from the recently detected signal were from the black box. But the difficulties of search are enormous. Experts from China National Oceanic Forecasting station say these days, the discovery of the pulse signal in the area is the sea floor of the mountain, the peak distance of about 1800 meters, near the surface of the sea trench and basin, trench close to 6000 meters deep, from seamounts to trench gap of more than 4000 meters, the entire seabed complex, the search for a difficult job. MH370 black box battery power in theory can only last 30 days, the current black box on the underwater Sonar beacon (underwater acoustic beacons, referred to as underwater beacon) transmission signal has exceeded this time. The search for the black box is becoming increasingly urgent. So how should the black box of the seabed be positioned and tracked? What technical means can be used? Towed sonar Locator (towed fish) and other black box positioning device The first step requires sea ships to lock the black box position as accurately as possible by receiving the acoustic signals from the black box. The first detection of the black box signal is the Shanghai Maritime Bureau of China Sea Patrol No. No. 01. The search and rescue ship is equipped with a black box locator produced by the American Teledyne Benthos, which can detect a depth of 5000 meters. Sea Patrol No. 01 has a side sweep sonar, can use about 100 meters of cable to put it into the sea, the black box for detection and positioning. Since then, the Australian warship Hai Dun also detected the black box signal, its detection depth of 6000 meters deep. The Hai Dun is carried with a sound wave receiver inside the towing device, which detects the black box signal by dragging the line slowly over the sea. To allow the locator to receive signals from the black box, the Hai Dun can only be searched at speeds of three knots per hour. The pulse signal was detected 5 times Hai Dun night, 10th. It is through multiple signal detection, Australia has been able to the black box to lock the approximate position. However, the detection device will be affected by sea conditions and marine life. To avoid the impact of sea surges on signal detection, the Australian side has begun to limit the number of ships it searches in the same waters as the Sea shield.