Following the discovery of a potential debris field at Amelia Earhart’s proposed crash site offshore Nikumaroro Island in the Western Pacific, Sonardyne International Ltd is now able to reveal that it’s Ranger 2 USBL tracking system together with a Lodestar GyroUSBL was the acoustic positioning technology of choice for the mission. Provided to Phoenix International, the expedition contractor, Ranger 2 was used to position both the ROV (Remotely Operated Vehicle) and AUV (Autonomous Underwater Vehicle) used in the underwater searches. The U.S. Navy’s primary source of ocean search and recovery expertise, Phoenix International was contracted by The International Group for Historic Aircraft Recovery (TIGHAR).
Upon arrival at Nikumaroro Island, believed to be where Earhart crash landed, the Bluefin-designed AUV was deployed to survey the primary search area. After each session, the data from the AUV’s suite of onboard sensors was reviewed by TIGHAR and Phoenix International sonar imagery experts to identify potential targets of interest. The ROV was then deployed to further investigate these targets. From onboard the Ka`imikai-o-Kanaloa (K-O-K) research vessel, Ranger 2 monitored the positions of the ROV and AUV in real time as they collected data and video imagery.
Ranger 2 is a high performance underwater target tracking system designed upon Sonardyne’s latest 6G® and Wideband 2 technology platforms. The system calculates the position of a subsea target by measuring the range and bearing from a vessel-mounted transceiver to an acoustic transponder on the target, a technique known as Ultra-Short BaseLine (USBL) positioning. Multiple subsea targets over a wide area and range of water depths can be simultaneously and precisely positioned without having to deploy any additional equipment into the water. This results in fast and efficient survey operations.
Because of the short term nature of the project, Phoenix International elected to install Sonardyne’s newly developed Lodestar GyroUSBL acoustic transceiver on their vessel. The instrument combines a survey grade AHRS (Attitude and Heading Reference System) and a USBL transceiver in a single unit that can be quickly installed on a vessel and requires only an initial out-the-box calibration. GyroUSBL can be subsequently moved from vessel-to-vessel without the need to perform a re-calibration, reducing delays and generating cost savings for owners.
“We are long-term users of Sonardyne technology and have found the accuracy and repeatability of Ranger 2 very impressive; we were receiving USBL hits from the AUV even though it was at the surface over 1000 metres away,” said Evan Tanner, Assistant Project Manager at Phoenix International . “Working on ships of opportunity, a full system calibration is not always possible so the accuracy of GyroUSBL was just fantastic.”
Ralph Gall, Technical Sales Manager at Sonardyne Inc. commented, “We’re delighted that Ranger 2 with GyroUSBL has played such an important role in this historic project. Reliable and accurate tracking is of great importance during missions such as this and we knew that Phoenix International would benefit from the precision of Ranger 2, GyroUSBL and 6G despite the rocky, hostile environment they were working in.”
The expedition departed on 3rd July on the 75th anniversary of Earhart’s disappearance. TIGHAR’s 10th expedition to the island, the mission was filmed by The Discovery Channel.
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Press Release, September 18, 2012