| 摘要 |
FIELD: physics; geophysics.SUBSTANCE: invention relates to sonar and can be used in surveying the lower surface of ice cover offshore, including offshore in high latitude conditions. The method includes placing hydroacoustic equipment in a water environment to obtain a picture of the visible part of the investigated object, making exposures associated with topographic plans of the upper ice surface, obtaining an image which is displayed on a monitor in a polar coordinate system in the form of bmp format graphic files. Survey is carried out from multiple levels. The hydroacoustic equipment is placed on a controlled mobile sea object and a receiving-transmitting device is placed on a rotary platform with three degrees of freedom. The image is obtained in three-dimensional space with display of the full volume of the ice cover and with breakdown of the volumes of the ice cover into sectors which are distinguished by frequency characteristics thereof. The size of said sectors is estimated, as well as the distance between elements of the ice field located at distances shorter than the duration of the probing pulse. A picture of the visible part of the investigated object - keels of hummocky formations, isometric morphostructures of the bottom surface of an ice formation - is obtained by constructing upper and lower boundaries of triangulated surfaces, determining the degree of curvature and the elementary form index of each volume of the ice cover for each sector of the surface of the relief; for complete mapping of the variation of the slopes of the relief of the ice cover at each point of the surface, the slope of the surface is determined as a value and direction of the gradient.EFFECT: high reliability of surveying the lower surface of ice cover.9 dwg |
