Patent ID: 7308105

Claim:
An environmental noise monitoring system, comprising: three or more sound level transducers arranged apart from each other in an environment containing one or more noise sources, each transducer is arranged to pick up sounds arriving from any direction and to transduce the sounds into electrical signals; sound level and direction measuring equipment, including: signal samplers connected to respective transducers to receive electrical signals representing environmental sounds and to sample the electrical signals, whereby pairs of sampled signals are formed with each pair representing sampled signals from two of the three or more sound level transducers; and a computer processor to: perform cross correlation calculations to generate a cross correlation function for each pair of sampled signals, identify local maxima in each cross correlation function; determine two possible sound arrival directions with respect to a fixed directional system for each identified local maximum; determine sets of possible sound arrival directions for each pair of sound level transducers in each cross-correlation function; compare the determined sets of possible sound arrival directions to find matches whereby the same sound arrival direction appears in determined sets of each cross-correlation function to within a predetermined tolerance and thereby indicate the direction of the one or more noise sources; and determine, for each match found, the sound pressure level of an associated noise source based on values of the cross-correlation functions at the associated local maxima.