Passive multipath ranging in sonars using auto-correlation processing

Passive sonar systems are used by submarines to detect the bearing (direction) and the range (distance) of the enemy target without passing on any indication about the submarines on which they are installed. In conventional passive sonar systems, the target is detected by listening to the underwater acoustic signals. Though these systems detect the bearing accurately, they suffer from the drawback of involved and time consuming computations. A method of auto-correlation processing of the underwater acoustic signals as recommended by W.S. Burdic [1] offers a solution to detect the range accurately and speedily. The concept behind this method, the details of the microcontroller based embedded proto model that was developed to prove the concept and the results thereof are presented in this paper.