Fault tolerance in autonomous acoustic arrays

Abstract

The problem of fault tolerance in autonomous disposable fiber-optic-based acoustic arrays is considered. The principal source of failures over relatively short mission times is node outage due to battery run-down resulting in possible network failure, degradation in the beam power pattern, and possible loss of critical processing elements. Network integrity in the presence of node failures requires an optical bypass capable of bypassing several adjacent 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 amenable to relatively simple solutions for the case of failures near the ends of the array, but failures near the center are more intractable. The loss of critical processing elements can be dealt with by distributing the processing load over processing elements located in each telemetry node of the network, thereby turning the array into a distributed parallel computer.