Multibeam sonar systems work by emitting a specific frequency of sound wave in a fan shape which bounces off the sea floor and returns to the receiver. The result is an image which shows detailed depth data and refreshes several times per second. High frequency multibeam sonar systems allow for higher resolution mapping at closer ranges, revealing enough detail to accurately identify underwater targets even in low visibility water conditions. Each multibeam sonar system is rated for a certain field of view (degrees of viewable image) and range (meter depth to sea floor before the sound bounces back).
As multibeam sonar systems have progressed, they have become smaller, lighter, more cost-effective, and easier to use. These advances have allowed multibeam sonar to be deployed to a wide range of vessels and underwater vehicles. Some of the smallest multibeam sonar systems, such as the Oculus M series multibeam sonar from Blueprint Subsea, are designed for use with inspection-class ROVs. When mounted to ROVs and AUVs, multibeam sonar is most often used to locate underwater objects. Interpreting a multibeam sonar image takes some experience and skill but it becomes much easier when you know what you’re looking for; Blueprint gives an example of what a Tire looks like, which is easily identified from the sea floor. When used for Search and Recovery, sonar is sometimes the only way to locate a lost person or object. When used for offshore oil and gas, sonar is often used to survey the sea floor in a lawnmower pattern, or for following underwater cables/infrastructure.
Whatever the application, multibeam sonar is an important option for all underwater vehicles which need to efficiently cover large search areas and become almost mandatory when used in low visibility or turbid environments where a live video feed is less effective. To learn more about how to mount a multibeam sonar system to a ROV, contact us!