The ultra short baseline acoustic positioning system is one of the broad classes of underwater acoustic positioning systems utilized for tracking underwater vehicles and drivers.
How does USBL Work?
Ultra short baseline (USBL) or super short baseline (SSBL) is the way of underwater acoustic positioning consisting of a transceiver. It is mounted on the pole under a ship and the transponder on the seafloor. A computer or a topside unit calculates the position from the ranges and the bearings measured by the transceiver.
The USBL with the built-in antenna enables accurate tracking and full-duplex digital communication.
Why Is USBL Implemented?
Technologically advanced USBL devices provide excellent performance implementing advanced data delivery algorithms, reinforcing addressing and networking, and offering easy control using a predefined set of commands and software configurable settings option. There is no need to switch between positioning and communication modes as USBL devices calculate the positioning data and acoustic transmissions.
USBL series are available so that oceanographers can select short- mid-and long-range devices for shallow or deep water applications.
Besides positioning and communication issues, oceanographers had to face the hurdle of measuring how fast the water column moves. This is resolved by using the Acoustic Doppler current profiler (ADCP).
How does ADCP work?
As an instrument for measuring how fast the water moves across an entire water column, ADCP is anchored to the seafloor that measures the current speed of the whole water column at equal intervals way up to the water surface.
It can be mounted either horizontally on the seawalls or bridge piling in rivers and canals to measure the current water profile from one shore to another and the bottom of the ships.
It uses the sound wave principle to measure water current, called the Doppler effect.
The sound wave has varied frequency or pitch when coming from the source and reaching the measuring device. It has a higher frequency when it comes to you comparatively when it moves away.
The ADCP works by transmitting sound pings constantly into the water.
When travelling, sound waves ricochet from particles suspended in the moving water and reflect the instrument.
Owing to the Doppler effect, sound waves bounce back from a particle moving away from the profiler, having a comparatively lower frequency than when they return. The particles moving toward the instrument send higher frequency waves.
The Doppler shift is the difference in the wave frequency that the profiler sends out and receives.
Prerequisites For ADCP Installation
If ADCP’s are bottom-mounted, there is a need for the anchor to keep them on the bottom. Also, batteries and an internal data logger are needed.
However, if the ADCP is vessel-mounted, a vessel with the power is needed along with the shipboard computer that receives the data. A GPS navigation system is also a must-have.
ADCPs have no external readout. The data collected must be stored and calculated on a computer using a software program designed with the ADCP data evaluation.
How Are Ships Anchored On The Modern Decks When ADCP Is Mounted?
Umbilical Winch is used on the modern decks that support the ships and boats’ umbilical, mooring and anchoring activities. These winches are built to have high resistance capabilities to withstand the harshest conditions of the weather and the sea.
Currently, umbilical winches are highly customizable marine equipment available in different sizes and configurations depending upon the requirements and the specifications.
Must Remember
Please make sure all the marine equipment meets safety, legislation, and quality-related standards.
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