Project Title:

Reduction of Turbulence-induced Noise in Aircraft Cabins

94-1	02.07	4973		

Reduction of Turbulence-induced Noise in Aircraft Cabins

Abstract:

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.

Key Words

Signal Separation Technologies	
4020 Iva Lane
Annandale, VA 22003