Vortex Observations by the Xonics Acoustic Radar at NAFEC.

A series of flight tests was conducted to demonstrate feasibility of the concept of the Xonics acoustic vortex detector. The first tests consisted of simultaneous observations in close proximity by both the Xonics equipment and an instrumented tower of vortices shed by a low-flying aircraft. A total of 55 runs, from which much of the data were gathered, were selected for analysis. Tests were also run to demonstrate the tracking capability of the acoustic sensor. Two principal modes of operation were employed, and many variations of equipment parameters were tested within each of them. An analysis is given of the system performance that may produce confident tracking at altitudes up to 1700 ft.