An automated sidescan sonar pipeline inspection system

The application of new developments in sonar signal processing and advances in computing power have resulted in the development of an automated sidescan sonar pipeline inspection system for surveying existing marine pipelines. Pipeline localization and tracking is controlled by a computer model that provides a graphic, real-time display of the pipeline height relative to the seabed and a visual representation of the incident sonar beam. This paper describes the computer algorithm used for automatically measuring pipeline span heights and addresses one method for compensating distortions found with the sidescan sonar beam width and tracking angle during typical survey operations. Analysis parameters input to the sonar system control the type and frequency of features automatically generated during survey operations. Limitations of the automated analysis to calculate measurements of span height and extent of pipeline burial are discussed when in-situ conditions deviate from the input analysis model. Automatic survey operations using Remotely Operated Towed Vehicles (ROTV's) are discussed using illustrative case histories in which ROTV position and steering controls are guided by the automated system using sonar incident reflections from the pipeline and seabed. The major benefits derived from using an automated sidescan sonar pipeline inspection system include better data quality, improved survey efficiency, and an overall reduction in operating costs.