A system for underwater survey operations

摘要

A system for underwater survey operations such as sea-bed, ice-mapping or pipeline tracking comprises an autonomous unmanned submarine vehicle having propulsion and steering means (4-8, 10, 11), a navigation system (38) comprising motion sensing and positioning means and an adaptive autopilot system (41) to propagate the vehicle through a predetermined submarine trajectory. A synthetic aperture sonar system (42) includes a sonar transmission and receiving array (43) of a length defining a limited physical aperture arranged on a surface part (32) of the vehicle to capture echo-signals in response to emission of sonar signals through a part of said trajectory defining a synthetic aperture of a length several times greater than said physical aperture. The autopilot system (41) is controlled to register any deviation of the propagation of the vehicle from said trajectory and provide a correspondingly corrected description of the predetermined trajectory within a margin of a fraction of the wavelengh of the sonar signals. Sets of echo signal values captured within said synthetic aperture are stored in memory means (44) and signal processing means (54-57) is provided for processing said stored sets and generating higher resolution image information data corresponding thereto.