Diving Deeper In Hydrographic Survey Details

A hydrographic survey also called a bathymetric survey, enables correct decision designing for the proper project inception. This survey ensures artisanal shelters and fishing ports building at the right location in easy and free of significant maintenance issues under all conditions.

There are different types of hydrographic surveys and equipment that work in correlation with the details required during the designing stage. The underwater tracking systems for hydrographic surveys produce a contour map about the sea bed depth arranged to show the line of equal depth from the coastlines. But this graphing has a problem of not knowing how far the survey boat is positioned from the shoreline at the time of depth recording.

For the underwater survey, both vertical depth and horizontal positioning measurements are done manually, which is low technology and low-cost methodology, or using sophisticated depth and position fixing equipment with high technology and high cost.

Purpose Of Hydrographic Surveys

Hydrographic service may be required for multiple purposes, ranging from simple project formulation, survey, or dredging or reclamation.

Seabed Mapping

For seabed mapping undertaken for extremely deep or shallow water, ocean survey equipment in different sizes and performance requirements.

These equipment are the accessories that contribute as the complete solution for underwater tracking ranging from sound velocity sensors, gondolas, cable, mounting kits, underwater GPS for robust positioning of the submarine target.

Importance Of Underwater Tracking System

Tracking underwater targets for their exact position is often a significant challenge in marine communities due to the absence of global positioning signals available in the areas reachable by satellite. To tackle this system, acoustic-based sensors such as LBL (Long baseline), SBL(Short baseline), And USBL (Ultra short baseline) are utilized for underwater localization and navigation by triangulating responses.

The most significant advantage of USBL systems is that they can be easily deployed (consisting of only two nodes, a Transmitter and a Transducer) over a long-range. However, with the distance and multipath issues, the precision of USBLs deteriorates.

An underwater vehicle tracks an underwater target for its position estimation. For this purpose, ultra-soft baseline measurement provides target position measurement at a low but regular update rate.

Tracking Underwater Targets With Sonar Imagery And Usbl

Multibeam sonar devices called acoustic cameras get imagery to provide high precision measurements with a limited field of view.

Research is being conducted on developing ocean survey equipment and tracking filters that combine both USBL and processed sonar image measurement to track underwater targets and provide reliable tracking estimates at a constant rate, especially where sonar or USBL measurements are not available or are erroneous.

This algorithm would be of higher safety where an underwater vehicle works in proximity to the human diver who emits air bubbles which hamper tracking performance.

A Portable Underwater Tracking System

The GPS intelligent Buoy is a portable underwater tracking system that consists of four buoys and one pinger. The pinger is attached to the underwater vehicle, which a scuba diver drives. It is used to map the limits of an oceanica meadow. For accuracy checking of this system methodology, it was tried on different limits types ranging from 2 to 25 m of depth. For this proposed method to be successfully integrated with the conventional system for mapping marine communities, the track acquisition time (one point per second), the recording speed (1 km h-1), and the mapping scale (more than 1:500) are acceptable.

Metrics Matters For Underwater Tracking Survey

Hydrographic surveys today are carried out using different methodologies, depending on the end-use of the study and the size of the survey area.