How Drones Enhance Bathymetric Surveys: A Safer and More Efficient Approach

Bathymetric surveys, which involve mapping the underwater topography of lakes, rivers, oceans, and other bodies of water, have historically been conducted using traditional manned boats equipped with sonar systems. While effective, these methods can be time-consuming, expensive, and sometimes risky, especially in shallow, remote, or hazardous waters. However, drones or unmanned aerial vehicles (UAVs) and unmanned surface vessels (USVs) are facilitating bathymetric surveys by offering a faster, more efficient, and safer alternative.

A bathymetric survey measures the depth and topography of the underwater surface, providing a detailed map of the waterbed. These surveys are essential for a variety of industries, including environmental monitoring, coastal engineering, underwater construction, and scientific research. Traditional methods often rely on echo sounders mounted on boats or ships, but drones now offer new possibilities for bathymetric data collection.

There are two primary types of drones used in bathymetric surveys, Aerial Drones (UAVs) and Surface Drones or USVs:

Data captured by the YellowScan Navigator at a community lake in Calgary, Alberta showcasing detailed topography and underwater mapping of the surrounding area.

Battery Endurance: Over 2 hours

Max Speed: 6 meters per second

Payload Capacity: 30 kg

Sounding Range: 0.15 m to 200 m

Motor: Robust, tangle-proof, DC-injected rotary motors, enabling smooth operation even in difficult conditions.

This system is optimized for ease of use with one-man operation, high accuracy, and straightforward navigation, making it suitable for a wide range of small-scale bathymetric and hydrological applications.

Battery Endurance: Over 2 hours

Max Speed: 5 meters per second

Payload Capacity: 30 kg

ADCP Compatibility: Integrates with sensors like M9, RTDP 1200, RiverPro, and RiverRay.

Echo Sounder Range: 0.15 m to 200 m

Navigation: Advanced autopilot and stable positioning

The Apache 4 is perfect for hydrologists needing precise, unmanned measurements with compatibility for industry-leading ADCPs and an array of high-performance hydrographic sensors.

Battery Endurance: Over 2 hours

Max Speed: 5 meters per second

Payload Capacity: 60 kg

Depth Range: 0.2 m to 275 m

Triple-Hulled Design: Provides stability in fast-moving currents and shallow waters.

Lightweight: Weighing only 15 kg for easy deployment, ideal for remote operations.

Optional LiDAR Sensor: Collects 300,000 points per second, providing both terrestrial and underwater 3D survey data.

With its superior features and performance, the Apache 6 is designed for professionals handling complex hydrographic surveys in challenging environments.

The Apache 3 PRO is best suited for smaller, shallow-water projects that require portable and easy-to-operate unmanned surface vehicles (USVs). In contrast, the Apache 4 excels in flow measurement, featuring integration with Acoustic Doppler Current Profilers (ADCP) for more comprehensive hydrological surveys. For high-resolution 3D bathymetric and underwater surveys, the Apache 6 offers a heavier payload capacity and advanced multibeam sonar systems. Each of these systems serves distinct use cases, ranging from straightforward bathymetric surveys to complex underwater explorations, catering to various project requirements in the field of hydrology.

Single-Beam Echo Sounders: This technology emits a sound pulse directly downward and measures the time it takes for the sound to return from the waterbed. It's commonly used for small-scale surveys.

Multibeam Echo Sounders: Multibeam systems emit sound pulses in a fan shape, covering a larger area and providing highly detailed bathymetric maps. These are often mounted on larger USVs and are used for detailed surveys of larger water bodies.

LiDAR (Light Detection and Ranging): While LiDAR is traditionally an aerial technology, it can be used in conjunction with bathymetric surveys to map the surface of the water. LiDAR is especially useful in shallow or clear water bodies where underwater features are visible from the air.

RTK (Real-Time Kinematic) GPS: Accurate positioning is critical for bathymetric surveys. RTK GPS ensures precise location data, which is essential for mapping water depths. Many drones used in bathymetry are equipped with RTK technology to enhance data accuracy.

Inertial Measurement Units (IMU): IMUs are used to compensate for the drone’s movement in the water, ensuring that sonar data remains accurate even in turbulent conditions.

Unlike conventional surveys that often rely on expensive manned vessels and large teams, drones and USVs significantly reduce costs by requiring fewer personnel and leveraging automated or remote operations. They can operate in hazardous or inaccessible environments, such as shallow waters, estuaries, or areas with submerged obstacles, thus minimizing risks to human operators. With their autonomous capabilities, drones can quickly survey large areas, efficiently navigating challenging conditions like strong currents or shallow depths that would hinder traditional boats. Moreover, the advanced sonar systems on these USVs and drones deliver high-resolution data, enabling the creation of highly accurate underwater maps that are crucial for industries such as coastal management, construction, and environmental research. With a diverse range of drones available from small portable unmanned surface vehicles (USVs) to larger, more robust models, bathymetric drones are adaptable for use in various environments, from small lakes to expansive oceanfronts.