LIDAR for Detection of Chemical and Biological Warfare Agents

Abstract

Remote detection of chemical and biological warfare agents and toxic gases in the atmosphere is of current interest to both the military and civilian agencies. Out of all currently available techniques, no single technique provides efficient detection against such threats at significant standoff distances. Light detection and ranging (LIDAR) technologies, based on the transmission of laser pulses and analysis of the return signals, have demonstrated impressive capabilities in remote detection of such toxic chemicals. LIDAR is a highly sensitive tool to detect the extremely low concentrations of various toxic agents present in the form of thin clouds at distances of few kilometer. The detection of these toxic clouds is based on the approach of first detecting and measuring the range of the clouds using the scattering phenomena and subsequently identifying the composition of toxic clouds using absorption and fluorescence phenomena. Laser Science and Technology Centre (LASTEC), Delhi has been working on the design and development of LIDAR systems for detection of chemical and biological warfare (CBW) agents. In this paper, theoretical analysis of differential absorption LIDAR (DIAL) for detection of chemical agents and fluorescence LIDAR for detection of biological agents has been discussed. For some typical parametric conditions, the received power levels from different ranges to detect specific concentrations of chemical or biological clouds have been computed and discussed. The technical details of the indigenously developed backscattering LIDAR, which detects and measures the distance of cloud layers up to 5 km is also presented.

High Repetition Rate Mid-Infrared Differential Absorption Lidar for Atmospheric Pollution Detection

“…The concentration of the target gas can be measured by detecting the difference between the returned signals of the two lasers [16]. Assuming the transmitted power is P t , the overall system efficiency is η, the telescope receiving area is A, the distance of the hard target is R, the reflectivity of the hard target is ρ, the absorption cross-sections of λ on and λ off are σ on and σ off , the atmospheric attenuation coefficient is α and the number concentration of the molecule is N(R), then the energy P received by the detector can be expressed as [17][18][19]:…”

War Impacts Studies Using Remote Sensing

“…In terms of assessing the war's damage caused to the environment, remote sensing data have shown the ability in detecting and indicating the impact of war on the environment For example, Veerabuthiran in 2011 used the LIDAR data for detection of biological warfare agents and toxic gases in the atmosphere [58]. Reuveny in 2010showed in his study the effects of warfare on the environment [59].…”

The Identification of Seven Chemical Warfare Mimics Using a Colorimetric Array

“…Additionally, the detection of the precursors and degradation products of these materials can be equally important [3]. Existing technology has shown that these devices can effectively detect such analytes, but requires high-tech, expensive, and large instrumentation, which makes them less than ideal for field applications [4,5,6,7].…”