bellhopModel
R2026bDescription
Add-On Required: This feature requires the Underwater Acoustic Channels add-on.
The bellhopModel object provides an interface between MATLAB® and the Bellhop beam tracing model for underwater sound propagation. Configure
Bellhop with parameters calculated in MATLAB. Use the object functions to calculate propagation paths and transmission losses
between underwater sources and receivers with Bellhop. Summarize and visualize the results in
MATLAB.
Note
The bellhopModel object requires the Bellhop beam tracing model, which
you must download and install separately from the Ocean
Acoustics Library. After you install Bellhop, use the bellhopConfiguration
function to specify the path to the Bellhop executable. For the Bellhop versions tested
with this object, see Supported Bellhop Versions.
Creation
Description
bhModel = bellhopModelbellhopModel object with default property values.
bhModel = bellhopModel(PropertyName=Value)
Properties
Object Functions
propagationPaths | Calculate underwater propagation paths using Bellhop |
transmissionLoss | Calculate transmission loss in underwater environment |
Examples
Create a bellhopModel object with the default parameters.
bhModel = bellhopModel
bhModel =
bellhopModel handle with properties:
SoundSpeed: [27×1 double]
SoundSpeedDepth: [27×1 double]
SSPInterpolationMethod: "linear"
BottomBathymetryProfile: "flat"
BottomReflectionCoefficients: [181×2 double]
SurfaceAltimetryProfile: "flat"
SurfaceReflectionCoefficients: -1
Show all properties
Set the sea water attenuation method to be the Francois and Garrison model.
bhModel.SeawaterAttenuation = "francois-garrison";
get(bhModel) SoundSpeed: [27×1 double]
SoundSpeedDepth: [27×1 double]
SoundSpeedRange: []
SSPInterpolationMethod: "linear"
BottomBathymetryProfile: "flat"
BottomReflectionCoefficients: [181×2 double]
BathymetryInterpolationMethod: "linear"
SurfaceAltimetryProfile: "flat"
SurfaceReflectionCoefficients: -1
AltimetryInterpolationMethod: "linear"
SeawaterAttenuation: "francois-garrison"
EffectiveSalinity: 19.3000
EffectiveTemperature: 33.5000
EffectiveAcidity: 7.5000
EffectiveDepth: 4000
NumRays: "auto"
RayElevationAngles: [-30 30]
StepSize: "auto"
BeamType: "geometric-hat"
RayTraceDepthLimit: []
RayTraceRangeLimit: []
ShowAllProperties: 0
You can also set properties of a bellhopModel object upon creation using name-value arguments. Create a bellhopModel object that uses piecewise cubic interpolation for its underwater sound speed profile.
bhModelModified = bellhopModel(SSPInterpolationMethod="pchip")bhModelModified =
bellhopModel handle with properties:
SoundSpeed: [27×1 double]
SoundSpeedDepth: [27×1 double]
SSPInterpolationMethod: "pchip"
BottomBathymetryProfile: "flat"
BottomReflectionCoefficients: [181×2 double]
SurfaceAltimetryProfile: "flat"
SurfaceReflectionCoefficients: -1
Show all properties
To run this example, you must have Bellhop installed, and you must also configure MATLAB with the Bellhop executable path by using the bellhopConfiguration function.
Create a bellhopModel object with the default configuration.
bhModel = bellhopModel
bhModel =
bellhopModel handle with properties:
SoundSpeed: [27×1 double]
SoundSpeedDepth: [27×1 double]
SSPInterpolationMethod: "linear"
BottomBathymetryProfile: "flat"
BottomReflectionCoefficients: [181×2 double]
SurfaceAltimetryProfile: "flat"
SurfaceReflectionCoefficients: -1
Show all properties
Calculate the propagation paths from a source at (0, 40, 1000) m with an operating frequency of 1000 Hz to a receiver at (20000, 35000, 1500) m.
fc = 1000; srcLocation = [0;40;1e3]; rxLocation = [20e3;35e3;1.5e3]; propPaths = propagationPaths(bhModel,fc,srcLocation,rxLocation)
propPaths = 9×7 table
PathLoss PathDelay PhaseShift AngleOfDeparture AngleOfArrival NumSurfaceReflections NumBottomReflections
________ _________ __________ ________________ ______________ _____________________ ____________________
87.628 26.84 90 0 -2.8651 0 -3.4277 0 0
89.403 26.791 0 0 9.7373 0 -9.9433 0 0
96.489 27.378 108.71 0 17.501 0 17.612 1 1
96.834 27.18 94.175 0 -16.733 0 -16.82 1 1
97.168 27.752 -38.287 0 -19.547 0 19.641 2 1
98.455 26.874 -125.13 0 15.284 0 -15.376 0 1
111.64 28.868 162.11 0 25.236 0 -25.301 1 2
113.84 29.425 -14.018 0 -27.367 0 -27.427 2 2
114.57 29.738 -12.728 0 28.364 0 28.421 2 2
Plot the eigenrays at the receiver location.
propagationPaths(bhModel,fc,srcLocation,rxLocation)
To run this example, you must have Bellhop installed, and you must also configure MATLAB with the Bellhop executable path by using the bellhopConfiguration function.
Create a bellhopModel object with a maximum ray tracing range limit of 20 km.
bhModel = bellhopModel(RayTraceRangeLimit=20e3);
Plot the transmission loss from a source at (500, 300, 700) m with an operating frequency of 1000 Hz.
fc = 1000; srcLocation = [500;300;700]; transmissionLoss(bhModel,fc,srcLocation)
Calculate the transmission loss for a receiver at (400, 3720, 2330) m.
rxLocation = [400;3720;2330]; tl = transmissionLoss(bhModel,fc,srcLocation,rxLocation)
tl = 71.6842
More About
References
[1] Munk, Walter H. “Sound Channel in an Exponentially Stratified Ocean, with Application to SOFAR.” The Journal of the Acoustical Society of America 55, no. 2 (1974): 220–26. https://doi.org/10.1121/1.1914492.
[2] Thorp, William H. “Analytic Description of the Low-Frequency Attenuation Coefficient.” The Journal of the Acoustical Society of America 42, no. 1 (1967): 270–270. https://doi.org/10.1121/1.1910566.
[3] Francois, R. E., and G. R. Garrison. “Sound Absorption Based on Ocean Measurements. Part II: Boric Acid Contribution and Equation for Total Absorption.” The Journal of the Acoustical Society of America 72, no. 6 (1982): 1879–90. https://doi.org/10.1121/1.388673.
[4] UNESCO, IWG. "The Practical Salinity Scale 1978 and the International Equation of State of Seawater 1980." Tenth Report of the Joint Panel on Oceanographic Tables and Standards (JPOTS) 25 (1981).
Version History
Introduced in R2026b
