A systems study of air-to-ground laser operations : statistical modelling of laser energy distribution in the transient regime

Abstract

Laser target designators have been used for precision guidance purposes for many years. High energy laser devices are also being developed for tactical operations. Both are examples of Class 4 devices that can produce hazardous laser output. A triangular system-risk model links system performance, the operational demand and the potential hazards associated with the system operation, and which provides the basis for a system-level probabilistic risk assessment analysis. An extension of the risk assessment model includes contextual information as an additional risk element. A decomposition model, comprising a linear combination of irradiance basis vectors based on transverse Hermite-Gaussian modes, is developed using multiple linear regression modelling for the analysis of transient mode laser output. A linear predictive mixture distribution for a multiplicative scintillation gain factor is developed from simulated optical turbulence modelling. A spatial analysis using techniques from computational topology shows an approximately uniform distribution of high scintillation gain values over the sample surface pro le. A statistical analysis of level set critical points provides a more detailed characterisation of the scintillation gain variability. The combined decomposition and scintillation gain modelling provides a `subsystemlevel' performance analysis within the overall risk assessment context.