The ABCS Program for the Analysis of Echo Sounder Returns for ...
The ABCS Program for the Analysis of Echo Sounder Returns for ...
The ABCS Program for the Analysis of Echo Sounder Returns for ...
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DSTO-GD-0215Appendix 1: Returned Ping Shape and EnergyVariations with Seafloor Depth<strong>The</strong> shape and energy <strong>of</strong> <strong>the</strong> returned signal can change significantly with seafloordepth (see Figure 13) as a result <strong>of</strong> ping dilation or compression, spreading losses, andabsorption.-60Returned Signal Power (dB re W)-90-12010m depth20m depth30m depth40m depth50m depth60m depth-1500 0.1 0.2 0.3Time (sec)Figure 13: How seafloor depth effects <strong>the</strong> returned signal. Calculated using Levels.Ping Dilation or CompressionWhen <strong>the</strong> depth <strong>of</strong> water changes, <strong>the</strong> start time <strong>of</strong> <strong>the</strong> returned ping changes alongwith <strong>the</strong> duration <strong>of</strong> <strong>the</strong> ping. <strong>The</strong> changing <strong>of</strong> <strong>the</strong> duration <strong>of</strong> <strong>the</strong> returned ping iscalled ping dilation or compression, depending on whe<strong>the</strong>r <strong>the</strong> ping's duration hasincreased or decreased.23
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