RaySolver
Model AcousticRayTracers.RaySolver
Description 2½D acoustic Gaussian beam tracer
Language Julia
Advantages Differentiable (forward mode)
Limitations Tell us and we will fix them!
Differentiability ForwardDiff 
RaySolver(env; kwargs...)

Julia implementation of a ray/Gaussian beam propagation model. The model supports complex environments, but retains differentiability.

Supported keyword arguments:

  • nbeams: number of beams to use (default: 0, auto)
  • min_angle: minimum beam angle (default: -80°)
  • max_angle: maximum beam angle (default: 80°)
  • ds: nominal spacing between ray points (default: 1 m)
  • atol: absolute position tolerance (default: 0.0001 m)
  • min_amplitude: minimum ray amplitude to track (default: 1e-5)
  • solver: differential equation solver (default: nothing, auto)
  • solver_tol: solver tolerance (default: 1e-4)

RaySolver is a differentiable 2½D Gaussian beam tracer similar to Bellhop, but fully written in Julia to be compatible with automatic differentiation (AD) tools such as ForwardDiff. Its implementation is largely based on the description in:

Example

using UnderwaterAcoustics
using AcousticRayTracers
using Plots

env = UnderwaterEnvironment(
  bathymetry = SampledField([200, 150]; x=[0, 1000], interp=Linear()),
  soundspeed = SampledField([1500, 1480, 1495, 1510, 1520]; z=0:-50:-200, interp=CubicSpline()),
  seabed = SandyClay
)
pm = RaySolver(env)

tx = AcousticSource(0, -50, 300)
rx = AcousticReceiver(1000, -100)
rays = arrivals(pm, tx, rx)

plot(env; xlims=(-10, 1010))
plot!(tx)
plot!(rx)
plot!(rays)
rxs = AcousticReceiverGrid2D(1:1000, -200:0)
x = transmission_loss(pm, tx, rxs; mode=:coherent)

plot(rxs, x; crange=70)
plot!(env; xlims=(0,1000), linewidth=3)

Notes

The RaySolver propagation model requires that the transmitter is located at \((x=0, y=0)\) and all receivers are located in the right half-plane (i.e., \(x>0\) and \(y=0\)). While this limitation can be worked around in the wrapper by a coordinate transformation, automatic transformation is not yet implemented.