Fault tolerance in autonomous acoustic arrays

The problem of fault tolerance in autonomous disposable fiber-optic-based a coustic arrays is considered. The principal source of failures over relativ ely short mission times is node outage due to battery run-down resulting in possible network failure, degradation in the beam power pattern, and possi ble loss of critical processing elements. Network integrity in the presence of node failures requires an optical bypass capable of bypassing several a djacent failed nodes. The effect of node failure on the beam power pattern is principally in the side lobes rather than in the main beam, and is amena ble to relatively simple solutions for the case of failures near the ends o f the array, but failures near the center are more intractable. The loss of critical processing elements can be dealt with by distributing the process ing load over processing elements located in each telemetry node of the net work, thereby turning the array into a distributed parallel computer. (C) 1 998 The Franklin Institute. Published by Elsevier Science Ltd.