Multibeam and sonar systems are used to map the underwater environment in detail. In this Blended Learning course, you’ll learn how sonar works, how multibeam technology is used to collect large numbers of depth measurements, and what factors influence the quality of those measurements. You’ll also learn how sonar data is processed, verified, and used to create detailed models of the seabed.
During this Blended Learning course, you’ll delve into multibeam and sonar data. You’ll discover how sound waves are used to measure the underwater environment and how modern multibeam systems collect large amounts of detailed information about the seabed.
The focus is on the entire data chain: from transmitting and receiving sound signals to processing, verifying, and visualizing the collected sonar data. You’ll learn why a multibeam survey is the result of multiple sensors and corrections that must be precisely combined.
Sonar uses sound waves that travel through water. A system transmits a sound signal, after which part of the signal is reflected by the seabed or an object and is received again.
You’ll learn how the distance to the seabed can be determined from the travel time of the sound signal. In doing so, you’ll be introduced to concepts such as frequency, pulse duration, beam width, reflection, and resolution.
You’ll also discover that different seabed materials can reflect sound in different ways. As a result, sonar data can provide not only information about depth but also insights into the properties of the seabed.
A traditional single-beam echo sounder primarily measures the depth directly beneath the survey vessel. A multibeam system, on the other hand, transmits multiple beams at different angles.
This allows a wide swath of the seafloor to be mapped during a single survey pass. You will learn how this so-called swath is formed and why its width and quality depend on factors such as water depth, beam angle, and the equipment used.
You will explore why multibeam is suitable for creating highly detailed and nearly comprehensive surveys of the seafloor.
You will also examine the differences between single-beam and multibeam and consider situations in which one technique or the other is most appropriate.
To calculate a reliable distance based on the travel time of a sound signal, it is necessary to know how fast sound travels through water.
The speed of sound is not the same everywhere. It is influenced by factors such as temperature, salinity, and water pressure. Furthermore, these properties can change with depth.
You will therefore be introduced to sound speed profiles and learn why they are important for multibeam measurements. An incorrect sound speed can cause the calculated position of measurement points to deviate from their actual position.
You will thus discover why knowledge of the properties of the water column is an essential part of reliable sonar and multibeam measurements.
A multibeam system does more than just determine the distance to the seafloor. To assign each measurement point a correct three-dimensional position, data from various sensors must be combined.
You’ll learn how GNSS is used to determine the survey vessel’s position and how motion sensors record roll, pitch, heading, and heave. You’ll also examine the position and orientation of the various sensors relative to one another.
In addition, you’ll learn about the importance of calibration. Minor deviations in the mounting or orientation of sensors can cause systematic errors in the final point cloud.
This makes it clear why an accurate multibeam result depends on the proper functioning and integration of the entire survey system.
A multibeam survey can yield millions of measurement points in a short period of time. This raw sonar data cannot be used as a reliable final product without further processing.
You’ll learn how position data, motion data, sound speed measurements, and sonar observations are combined. The dataset is then checked for noise, outliers, and other anomalous measurements.
You’ll also examine overlap between different survey lines and explore ways to assess the quality and consistency of a survey.
After processing, a three-dimensional point cloud of the seabed is generated. This can then be used to create digital seabed models, depth charts, profiles, and other hydrographic products.
During the Blended Learning course, you’ll work with provided multibeam and sonar data. You’ll examine how the data is structured, assess its quality, and process the results into usable geographic information.
You’ll work on assignments such as:
By the end of the course, you will understand how sonar and multibeam work, which sensors and corrections are needed to obtain reliable measurements, and how raw sonar data is processed into a three-dimensional representation of the seabed. You will be able to evaluate, process, and use multibeam data in general terms within hydrographic and Geo-ICT applications.
You’ll receive 1-on-1 guidance. After signing up, our course coordinator will contact you to schedule your first session.
Do you have questions about the course content? Or are you unsure whether the course aligns with your learning goals or preferences? Would you prefer an in-house or private course? We’d be happy to help.
A multibeam echo sounder is a sonar system that transmits multiple sound signals simultaneously at different angles. This allows a wide swath of the seabed to be surveyed in a single pass.
A single-beam system primarily measures the depth directly beneath the survey vessel. A multibeam system simultaneously measures many points across a wide swath, providing a much more detailed and virtually comprehensive picture of the seafloor.
While underway, the survey vessel moves through waves and currents. Movements such as roll, pitch, and heave affect the direction and position of the measured sonar beams. These movements must therefore be recorded and corrected in order to accurately determine the seabed.
The raw sonar data is combined with position, motion, and sound speed data. After correction and quality control, erroneous measurement points can be removed, and a detailed 3D seabed model or a bathymetric map can be created.
