Simulation of Acoustic Propagation of Elevated Sources to a Microphone Array
Abstract
A MATLAB code is developed to propagate harmonic signals from elevated sources in the lower audio band (30500 Hz) to a small microphone array near the ground using standard models to simulate propagation speed profiles, wind speed and direction, ground reflection, and turbulence to predict the phase and relative amplitude of a received narrowband signal. Wind speed and temperature profiles are modeled using MoninObukhov similarity theory. Signal propagation from a source is simulated using ray tracing through a stratified atmosphere (from Pierce) and a finite-difference, time-domain method. The ground reflection is modeled using either a one-parameter model (by Delany and Bazley) or a two-parameter ground impedance model (by Attenborough et al.). Spatial coherence of the signal at the array is modeled using a statistical approach by Kozick et al. The coherence of signals at different microphones is reduced based upon the range of the source and distance between microphones. Using these models, propagation time from the source to the microphone array for direct and multipath signals is calculated using custom 3D interpolation algorithms. The errors associated with these algorithms are analyzed by testing with a homogeneous atmosphere. This code is a building block for simulating more complex signals and a resource for testing beamforming algorithms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2020
- Accession Number
- AD1109764
Entities
People
- Geoffrey H. Goldman
Organizations
- United States Army Combat Capabilities Development Command