A direct method for measuring acoustic ground impedance in long-range propagation experiments.

A method is reported for determining ground impedance in long-range propagation experiments by using the definition of impedance directly. The method is envisioned as way of measuring the impedence at multiple locations along the propagation path, using the signals broadcast during the experiment itself. In a short-range (10 m) test, the direct method was in good agreement with a more conventional model-based least-squares method.