Results of experiments to detect moving vehicles with a one-bit correlator
Robert H. Gonter · The Journal of the Acoustical Society of America · 1990
Moving vehicles such as automobiles, trucks, and aircraft can be tracked with a one-bit correlator using a technique similar to pattern velocity computers [G. R. Ochs and O. F. Miller, Rev. Sci. Instrum. 43, 879–882 (1972)]. Using two microphones spaced 30 cm apart, vehicles passing at a distance of 30 m or farther give significant correlation when the signals are in phase. Beamforming is easily done with shift registers so that the direction of movement can be determined as vehicles cross the beams. Although the correlations are confounded when more than one vehicle is passing, approximate vehicle counts were made using an AIM 65 microcomputer. It is possible that aircraft could be tracked by their sound using a three-microphone array and an oscilloscope with X-Yinput capability.