Smart Structure Active Sonar Echo Cancellation Using Frequency Scheduled Control

Practical applications of smart structure technology to active acoustic noise control demand high performance at low cost. Typically, performance increases achieved by reducing control system latency are expensive. Furthermore, sonar echo cancellation is concerned with a wide frequency range for which linear time-invariant (LTI) controllers provide inadequate performance, and no direct error measurement is available to drive adaptive controllers. Real-time estimators of the cancellation error have been proposed to enable the use of adaptive controllers, however this significantly increases the system cost. In this paper, we introduce a frequency scheduled control architecture for echo cancellation which achieves adaptive control performance at LTI control prices, by exploiting the narrow instantaneous bandwidth commonly associated with individual sonar pings.