| || Parametric Study of Differential Absorption Lidar System for Monitoring Toxic Agents in the Atmosphere
Author : Veerabuthiran, S.;Dudeja, Jai Paul
Source : Defence Science Journal ; Vol:57(5) ; 2007 ; pp 755-764
Subject : 621.38 Electronics
Keywords : Monitoring;Remote detection;DIAL;Toxic agents;Differential absorption lidar
Abstract : Differential absorption lidar (DIAL) techniques are advantageously used these days for detecting and monitoring traces of toxic agents located at several kilometer in the atmosphere. A theoretical study has been carried out to simulate the performance of a multiwavelength DIAL system. Clouds of hydrazine, unsymmetr ical dimethylhydrazine (UDMH), and monomethylhydrazine (MMH), located at various ranges up to 5 km in the atmosphere, have been taken as examples of the toxic agents. It has been shown that a given lidar system cannot detect any of these agents with a specific cloud thickness if the concentration of that agent is below a certain value (Nmin). It has also been shown that if the concentration level of a given agent is above a certain value (Nmax) at a particular distance, this value cannot be quantified for a given lidar system although the identity as well as the location of that agent can still be determined. Further, for some typical parametric conditions, the required energy levels of the laser to detect specific concentrations of these agents at different distances have been computed. Power levels of the return signals and the SNR values from different ranges have also been calculated for each of these toxic agents for a given value of the laser transmitter energy.