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Using the bottom track feature, the track of the boat as well as the cross sectional area is estimated after adjustment for left and right bank areas. The discharge can then be calculated as the dot product between the vector track and the current velocity. The method is in use by hydrographic survey organisations across the world and forms an ...
Doppler instruments are more common. An instrument of this type is the Acoustic Doppler current profiler (ADCP), which measures the water current velocities over a depth range using the Doppler effect of sound waves scattered back from particles within the water column. The ADCPs use the traveling time of the sound to determine the position of ...
Besides navigating through canyons and other difficult underwater terrain, there was also a need to establish the position of the submarine prior to the launch of a nuclear missile (ICBM). In 1981, acoustic positioning was proposed as part of the U.S. military's MX missile system. [10] A network of 150 covert transponder fields was envisioned.
The system concept (Figure 1) utilizes an array eight to ten GIBs (Figure 2) moored in a 2 km by 2 km array. In the case of the TARGT GIB, the GPS and RF antennas are located on top of the sensor and the hydrophone, or underwater acoustic transducer, is located on the bottom. The device is approximately 6 ft tall and weighs 35 lbs.
Tracking or navigation operations. Following the baseline deployment and survey, the acoustic positioning system is ready for operations. In the long baseline example (see figure 1), an interrogator (A) is mounted on the ROV that is to be tracked. The interrogator transmits an acoustic signal that is received by the baseline transponders (B, C ...
USBL (ultra-short baseline, also known as SSBL for super short base line) is a method of underwater acoustic positioning. A USBL system consists of a transceiver, which is mounted on a pole under a ship, and a transponder or responder on the seafloor, on a towfish, or on an ROV. A computer, or "topside unit", is used to calculate a position ...
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Rather than tracking both vehicles with a positioning system from the surface which would result in degraded accuracy as the pair's deployment distance, the SBL baseline transducers are mounted on MEDEA. yielding the position of JASON relative to MEDEA with good accuracy independent of the system's deployment depth. The reported accuracy is 0 ...