Line-of-sight sound propagation in a random moving medium

In this chapter, we consider line-of-sight sound propagation through a random moving medium. This topic is relevant, for example, to outdoor sound propagation from elevated sources (such as helicopters, airplanes, and rockets) to microphones on the ground. It also occurs in propagation from acoustic sources on the ground (such as gun and rifle shots, rocket launches, and explosions) to elevated acoustic sensor arrays, such as those suspended below aerostats or installed on helicopters and unmanned aerial vehicles. If there is only a single, dominant propagation path, the effect of atmospheric refraction on the signal statistics is often relatively small, and such effects can be determined approximately assuming straight line sound propagation. Applications of line-of-sight propagation include source localization [ 260 ], sonic boom propagation in a turbulent atmosphere [ 41 , 48 , 101 , 370 , 426 ], auralization of flying aircraft [ 57 , 140 , 374 , 393 ], and acoustic travel-time tomography of the atmosphere ( section 3.7 ).