Polarization lidar for shallow water depth measurement

Area of Science:

• Oceanography
• Remote Sensing
• Optical Engineering

Background:

• Accurate shallow water depth measurement is crucial for various applications.
• Existing bathymetric techniques face limitations in resolution and accuracy for shallow depths.
• Polarization lidar offers potential for enhanced water body profiling.

Purpose of the Study:

• To develop and demonstrate a novel polarization lidar system for precise shallow water depth measurement.
• To overcome the limitations of current laser bathymetry systems in shallow water environments.
• To improve the minimum resolvable water depth determination.

Main Methods:

• Utilized a bathymetric, polarization lidar system operating at 532 nm.
• Employed a single photomultiplier tube and polarization attributes to isolate surface and floor returns.
• Implemented constant fraction detection schemes with a constant fraction discriminator and time-to-digital converter.

Main Results:

• Demonstrated measurement of 1 cm water depths with an uncertainty of ±3 mm in laboratory tests.
• Achieved better than 1 order of magnitude improvement in minimum resolvable water depth.
• Successfully simulated glacial meltpond conditions using an ice floor.

Conclusions:

• The developed polarization lidar technique enables new approaches for shallow depth determination.
• The system offers improved accuracy without compromising deep water measurement capabilities.
• This novel approach is suitable for designing laser bathymetry systems for remote platforms.