Multibeam sonar backscatter data acquisition and processing: guidelines and recommendations from the GEOHAB Backscatter Working Group

Backscatter data acquired with multibeam sonars are now commonly used for the remote geological interpretation of the seabed. The systems hardware, software, and processing methods and tools have grown in numbers and improved over the years, yet many issues linger: there are no standard procedures for acquisition, poor or absent calibration, limited understanding and documentation of processing methods, etc.

A workshop organized at the GeoHab (a community of geoscientists and biologists around the topic of marine habitat mapping) annual meeting in 2013 was dedicated to seafloor backscatter data from multibeam sonars and concluded that there was an overwhelming need for better coherence and agreement on the topics of acquisition, processing and interpretation of data. The GeoHab Backscatter Working Group (BSWG) was subsequently created with the purpose of documenting and synthetizing the state-of-the-art in sensors and techniques available today and proposing methods for best practice in the acquisition and processing of backscatter data.

Two years later, the resulting document "Backscatter measurements by seafloor-mapping sonars: Guidelines and Recommendations" was completed¹. The document provides:

1. An introduction to backscatter measurements by seafloor-mapping sonars;
2. A background on the physical principles of sonar backscatter;
3. A discussion on users’ needs from a wide spectrum of community end-users;
4. A review on backscatter measurement;
5. An analysis of best practices in data acquisition;
6. A review of data processing principles with details on present software implementation; and finally
7. A synthesis and key recommendations.

This presentation reviews the BSWG mandate, structure, and development of this document. It details the various chapter contents, its recommendations to sonar manufacturers, operators, data processing software developers and end-users and its implication for the marine geology community.