Passive acoustic system for tracking lowflying aircraft

The following study presents the acoustic aircraft detection system designed for automated detection, classification and tracking of low-flying aircraft using a network of passive acoustic sensors. The system consists of multiple autonomously powered sensor nodes, each equipped with a microphone cluster, cameras and electronics that perform pre-processing and transmit the results wirelessly to a central processing station. The station fuses the data from sensors for finding the direction of arrival (DOA) of aircraft sounds then uses triangulation techniques for the target localisation. The calculated tracks were used for steering the cameras to the acoustically tracked target to capture pictures. The extended test spanning more than two years has uncovered many challenges that are part of such deployment including the impact of the weather, natural and man-made interfering sources of noise, effects of terrain and the variety of types and modes of operation of the targets of interest. During the deployment period, the system detected a significant number of targets of interest. Several control tests with different aircraft providing ground truth GPS for comparison with the acoustic tracking was also conducted.