Profiling data is collected using a narrow-beam sonar head sealed in a sonar enclosure. With this digital system, the frequency and sound pulse can be calibrated to suit conditions.

The sonar head, when positioned underwater, generates an acoustic pulse in a narrow cone. A profile of the pipe is built as the sonar head mechanically steps about its axis. When the sound pulse hits a target, it bounces back and the echo appears as a data point.