Multibeam Sonar Swath Footprint Calculator
Hydrographic surveying & marine geophysics: Compute swath coverage width, along-track and across-track footprint dimensions, sounding density, and travel time.
Sonar Geometry & Survey Parameters
Swath & Footprint Coverage
Recommended Tools & Equipment
Tested hardware and components for high reliability
Frequently Asked Questions
How does water depth affect multibeam ping rate?
Sound travels at approximately 1500 m/s in seawater. As water depth increases, the two-way travel time (TWTT) for outer acoustic beams increases substantially (e.g., at 1000 m depth and 120° swath, slant range is 2000 m, requiring 2.67 seconds for return). The sonar must wait for echoes before transmitting the next ping unless multi-ping dual-swath technology is used.
Why does outer beam footprint size increase across-track?
At nadir, sound waves hit the seabed orthogonally. At outer sector angles (e.g. 60° to 75° from vertical), sound waves strike the seabed at oblique grazing angles. The beam projects onto the slope as an elongated ellipse, scaling by 1/cos²(θ) across-track.
What is the difference between beam spacing and sounding density?
Beam spacing is the angular or metric distance between individual beam centers across the fan. Sounding density measures the number of discrete depth soundings collected per square meter of seabed, factoring in vessel speed, ping repetition rate, and beam count.