the present invention relates to a space - invariant independent component analysis and electronic nose for detection of selective chemicals in an unknown environment , and more specifically , an approach to analysis of sensor responses to mixtures of unknown chemicals by an electronic nose in an open and changing environment . it is intended to fill the gap between an alarm , which has little or no ability to distinguish among chemical compounds causing a response , and an analytical instrument , which can distinguish all compounds present but with no real - time or continuous event monitoring ability .