The purpose of the proposed project is to learn to reduce aircraft cabin noise stemming from turbulence generated at the aircraft's boundary layer, using a new patented technique of multi-channel noise cancellation proprietary to Signal Separation Technologies. NASA has already made substantial progress in applying active noise cancellation to the reduction of cabin noise stemming from engine vibration. On the other hand, eliminating the noise coming from the turbulent boundary layer is somewhat more complicated. Here, the required multiple noise reference sensors and multiple actuators necessitate the use of a multi-channel noise cancellation procedure which will reliably remove the always-present redundancies from the corresponding correlation matrices. The classical procedure for performing multichannel noise cancellation contains no provision for the elimination of these redundancies, but Signal Separation Technologies' patented method using singular-value decomposition (SVD) to eliminate them is robust and a prime candidate method for solving this problem.The immediate application of the multi-channel active noise cancellation cancellation system to be developed will be the suppression of aircraft cabin noise coming from multiple sources such as the turbulence induced along the aircraft surface. The market for this innovation will include makers of military and civilian aircraft. Such manufacturers will be solicited for the formation of joint ventures to develop and market a noise canceller for use in aircraft.Other potential markets for a successful multi-channel active noise cancellation system such as this will be the automobile industry, which also has shown considerable interest in noise cancellation techniques for use in cars. Automobile companies might provide an additional source of funding, based on the availability of a working prototype noise canceller for aircraft.
