Underwater LiDAR Technology for Marine Mapping and Surveying

Yellowscan Navigator Underwater LiDAR Scanner

Underwater LiDAR (Light Detection and Ranging) is a remote sensing technology that uses laser light to detect and map underwater features with high precision. Unlike traditional sonar, which relies on sound waves, LiDAR uses laser pulses. These typically green or blue wavelengths penetrate water effectively to measure distances to seafloor features, underwater structures, or suspended particles. This allows for creating high-resolution 3D maps of the ocean floor, harbor installations, coral reefs, and submerged archaeological sites.

Adaptations for aquatic environments include water-resistant housings, enhanced laser emitters, optical components such as photodetectors optimized for low-light underwater conditions, and integration with other marine survey tools. Systems may include cooling systems to ensure performance stability, timing electronics for accurate pulse measurement, and data acquisition systems to manage large volumes of collected data.

Article Navigation

• How does LiDAR work underwater?
• Applications of underwater LiDAR
• Supporting technologies
• Types of underwater LiDAR systems
• Underwater LiDAR vs sonar
• The broadening scope of underwater LiDAR

How does LiDAR work underwater?

Underwater LiDAR works by emitting a laser pulse and measuring the time it takes for the reflected light to return from underwater surfaces. Special considerations are required because light behaves differently in water than in air, undergoing refraction, scattering, and absorption. Systems often integrate with inertial measurement units (IMUs), GPS modules, and RTK correction signals to provide precise positioning and motion compensation.

Advanced models include underwater LiDAR and laser scanners mounted on remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), or surface vessels. These setups typically include a stabilization platform to counteract motion and a data storage unit to handle the extensive datasets generated during mapping operations.

Applications of Underwater LiDAR

Underwater LiDAR is used across various scientific, commercial, and defense-oriented applications. Its ability to provide accurate, real-time, and high-resolution data makes it indispensable in numerous fields:

Marine Surveying and Mapping

LiDAR systems conduct underwater surveying for coastal engineering, environmental impact assessments, and infrastructure development. Bathymetric LiDAR systems can produce detailed bathymetric maps essential for hydrodynamic modeling, sediment transport analysis, and port and harbor planning.

Pipeline Inspection and Subsea Infrastructure Monitoring

Oil and gas operators use LiDAR to inspect underwater pipelines and cables. High-resolution scans reveal damage, deformation, or sediment buildup along pipelines. This method is non-invasive, non-destructive, and allows for consistent monitoring with minimal operational disruption.

Marine Archaeology and Shipwreck Exploration

Underwater LiDAR plays a critical role in discovering and documenting submerged archaeological sites. Its ability to produce detailed topographies aids in preserving historical sites and supports research into ancient maritime activity.

Environmental Monitoring and Habitat Mapping

Marine biologists and conservationists employ LiDAR for reef monitoring, seagrass bed mapping, and fish habitat analysis. Its non-destructive nature is ideal for fragile ecosystems and allows for repeated measurements over time to detect changes.

Dam Inspection and Reservoir Management

LiDAR systems are deployed to inspect submerged portions of dams and reservoirs. These systems detect cracks, sediment accumulation, and structural deformations, often in areas difficult to reach with divers.

Underwater Mine Detection and Security

Military and security agencies use LiDAR for underwater mine detection, port and harbor security, and reconnaissance missions. The speed and accuracy of underwater LiDAR allow the safe identification of threats in complex underwater environments.

Oceanographic Research and Bathymetric Studies

Ocean scientists leverage LiDAR to create high-resolution maps of the ocean floor, helping to advance our understanding of geological features, underwater ridges, and sediment patterns. This data supports broader initiatives in climate science and marine ecology.

Supporting Technologies

Underwater LiDAR systems rarely operate in isolation. They are part of integrated systems combining navigation systems, attitude heading reference systems (AHRS), and positioning systems to maintain accurate data capture. These technologies correct for pitch, roll, and yaw, ensuring that mapping outputs are precise spatially.

Communication interfaces allow real-time data transmission, while control software interprets raw data into usable models and visualizations. Systems also rely on a combination of rangefinder modules, underwater laser emitters, and photodetectors to optimize performance under different environmental conditions. For extended missions, particularly those using AUVs or ship-based platforms, a robust data acquisition system is essential to ensure all collected information is preserved for analysis.

Types of Underwater LiDAR Systems

Voyis’ Insight underwater scanners are based on a form of LiDAR

Depending on the application, different types of underwater LiDAR systems may be used:

• 3D LiDAR systems: Offer comprehensive three-dimensional imaging, particularly useful for terrain mapping and infrastructure inspection.
• Bathymetric LiDAR: Specially designed for measuring depth and creating bathymetric maps. These systems can be airborne or underwater-based.
• Underwater laser scanners: Compact units that provide detailed scans of nearby objects or surfaces, often used in confined areas or during detailed inspections.
• Combined sonar-LiDAR systems: In hybrid setups, sonar may be used for deeper or more turbid waters, while LiDAR provides detail in clearer, shallower areas.

Underwater LiDAR vs Sonar

While both LiDAR and sonar are used for underwater sensing, they operate on fundamentally different principles. Sonar uses acoustic waves and is generally more effective in turbid or deep-water conditions. LiDAR, on the other hand, provides much higher resolution in clearer water and is ideal for applications requiring fine detail, such as underwater archaeology or close-range infrastructure inspection.

LiDAR offers a significantly faster data acquisition rate and is less affected by background noise in the marine environment. However, it can be limited by water clarity, with performance diminishing in murky or particulate-heavy waters.

The Broadening Scope of Underwater LiDAR

By delivering high-resolution, three-dimensional representations of submerged environments, it enables better decision-making in fields ranging from environmental monitoring to defense and infrastructure. When integrated with complementary technologies like GNSS, AHRS, and real-time positioning systems, underwater LiDAR becomes a critical tool in the modern marine scientist’s toolkit. With ongoing advances in laser emitters, photodetectors, and data processing algorithms, its utility and range of applications will only expand, helping to map the ocean floor and safeguard marine environments more accurately than ever.