Hydrographic LADS and LIDAR

Brief description


LIDAR technology utilizes the reflective and transmissive properties of water and the sea floor to enable measurement of water depth using a laser. When a light beam hits a column of water, part of the energy (the infrared pulse) is reflected off the surface and the rest (the blue-green pulse of the visible spectrum), unless absorbed by particles in the water, is transmitted through the column. As the light (blue-green) travels through the water column and reflects off the seafloor, scattering, absorption, and refraction all combine to limit the strength of the bottom return, and therefore the system's maximum extinction depth (a function of water clarity). The infrared (IR) pulse reflection off the water surface is a very strong return, while the blue-green pulse bottom return is much weaker. The water depth is calculated (to the centimeter) from the time difference between the IR surface return and the blue-green bottom return.

See NOAA's summary table at summary

 

 

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Laser Airborne Depth Sounder

Tenix LADS Mk II

Where water clarity is excellent, Tenix's LADS is capable of providing one of the most efficient and cost-effective methods of accurately surveying complex and large areas that are environmentally sensitive waters down to 70 metres deep. Tenix provides hydrographic survey systems and services using its Laser Airborne Depth Sounder (LADS) (451 KB PDF) technology mounted in a Dash 8-202 aircraft, working for governments and companies worldwide. The original LADS has been in routine survey operation with the Royal Australian Navy Hydrographic Service since February 1993, and has surveyed more than 100,000 sq km in 12 years of operation.

The LADS system acquires accurate, high density, digital bathymetric data, for specifications (300 KB PDF) and for case studies.

Project Location: Passagio dei Fornelli, Sardinia, Italy
Customer’s Name: Compagnia Generale Ripreseaeree
Date: 16 October 2003

Courtesy: Tenix

Optech

Where water clarity is excellent Optech's SHOALS ( LIDAR ) Airborne Laser Bathymeters are a well-proven tool, used for hundreds of surveys in a wide range of applications. Based on the same principle as sonar, but using light instead of sound, SHOALS gather shallow water, shoreline and topographic (ground elevations) data simultaneously, integrating land and water measurements in the same data set. Depth and position measurements are accurate to IHO Order 1.

The Optech system acquires accurate, high density, digital bathymetric data. For specifications (1.8 MB PDF) and for case studies .

Courtesy: Optech

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