| 主权项 |
1. A method of inspecting an underwater surface, comprising:
projecting, from a moving underwater vehicle (UV) travelling substantially parallel to the underwater surface, at a separation distance from the underwater surface, and at a transit speed relative to the underwater surface, transmitted sound in an FM sweep toward the underwater surface, wherein the FM sweep has a lowest frequency, a highest frequency, and a sweep time interval between the lowest frequency and the highest frequency, wherein the lowest frequency is above about 2.0 MHz, and wherein the projecting comprises projecting the transmitted sound in a transmitting beam pattern having a beam pattern center axis; receiving, with the underwater vehicle (UV), backscattered sound from the underwater surface responsive to the transmitted sound, wherein the receiving is performed with a plurality of receive elements having respective centers arranged in a line array with a physical aperture; processing a plurality of signals from the plurality of receive elements with synthetic aperture processing to result in a plurality of motion compensated signals; beamforming using the plurality of motion compensated signals to generate a beamformed signal indicative of a synthetic aperture longer than the physical aperture; and forming an image of the surface using the beamformed signal. |
