Abstract: A system having an optical remote sensor where sensing can be achieved from distance, and therefore without necessarily making contact with the threat chemical, with one or more in-situ sensors where sampling of air is required, and where at least one sensor is cross-reactive. Aspects of some of the various systems capable of achieving, but not limited to thereto, the following advantages: (a) by the optical sensor: long range advanced warning, rapid large volume analysis, fast response continuous monitoring for protection against bursts, safety to the operator, (b) by the in-situ sensor: high sensitivity, (c) by the combination of sensors, high specificity, better avoidance of interferences by chemicals and (d) by the inclusion of cross reactive characteristics, the ability to learn response to new chemicals.

Abstract: Disclosed herein are methods of analysis for unmixing non-linear, cross-reactive sensors and related system. Use of the disclosed methods, related systems and computer program product permits better analysis of the magnitudes of various stimulants including but not limited to chemical concentrations. One method may add one or more additional signal vectors to the sensor response before linearizing each channel. A second method may add one or more exponential terms to the response curve when using curve parameterization to unmix the sensor response. A third method may use non-linear iterative solutions that estimates an optical depth, linearizes the optical depth, solves for a correction to the estimated optical depth, and updates the optical depth. Also, the disclosed methods and related systems include combinations of the methods described herein.

Abstract: A system and method of alternately purging an in-situ sensor with clean fluid and sampling a fluid volume of interest, in order to eliminate drifts and errors associated with the absorption of chemicals to the sensing elements of in-situ sensors. The system and method effectively processes the output of the in-situ sensor using this alternating sample and purge cycle to detect and identify chemicals accurately and reliably. The system and method also effectively reduce errors induced by temperature and humidity drifts in the ambient, and the sampled, fluid.

Abstract: A method and a low-cost, robust and simple system for remote sensing and analyzing spectral properties of targets as a means to detect and identify them is introduced. The system can be highly portable but is usable in fixed locations or combination thereof. An aspect of the method and system includes the capability to distribute, modulate, aperture and spectrally analyze radiation emitted or absorbed by a volumetric target chemical species (solid, liquid or gas) or a target surface. Radiation is first collected by a single light gathering device, such as a lens, telescope, or mirror, and then distributed to multiple detectors through spectrally discriminating components and if desired through apertures to achieve this desired detection and identification.

Abstract: A method and a low-cost, robust and simple system for remote sensing and analyzing spectral properties of targets as a means to detect and identify them is introduced. The system can be highly portable but is usable in fixed locations or combination thereof. An aspect of the method and system includes the capability to distribute, modulate, aperture and spectrally analyze radiation emitted or absorbed by a volumetric target chemical species (solid, liquid or gas) or a target surface. Radiation is first collected by a single light gathering device, such as a lens, telescope, or mirror, and then distributed to multiple detectors through spectrally discriminating components and if desired through apertures to achieve this desired detection and identification.

Abstract: A remote sensor for use as a handheld, mobile or stand-alone sensor has first (12) and second (16) optical paths, light collecting optics, a sample filter (10) assembly positioned in a first optical Path (12), a reference filter (14) assembly positioned in a second optical path (16), a detector assembly to detect the filtered light r other radiation, and a detector output comparison device such as BRD to minimize the effects of common background noise components, differences in light or other radiation source power, and absorption or emission by interfering species.