Methodology for comparing worldwide performance of diverse weight-constrained high energy laser systems

Bartell, Richard J.; Perram, Glen P.; Fiorino, Steven T.; Long, Scott N.; Houle, Marken J.; Rice, Christopher A.; Manning, Zachary P.; Bunch, Dustin W.; Krizo, Matthew J.; Gravley, Liesebet E.

doi:10.1117/12.603384

Cited by 27 publications

(18 citation statements)

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“…These tools include the following MatLab toolboxes: Scaling for High Energy Laser and Relay Engagement (SHaRE) 1 , Scaling Code for Airborne Laser Engagement (SCALE) 2 and its underlying toolboxes: ATMTools 3 , EngagementTools, SimTools, and the High Energy Laser End to End Operational Simulation (HELEEOS) 4 . Realistic and accurate prediction of irradiance delivered to the target is the critical initial step in the Scenario Simulation chain and is provided in the current study by SCALE.…”

Section: Simulation Model Descriptionmentioning

confidence: 99%

A worldwide physics-based high spectral resolution atmospheric characterization and propagation package for UV to RF wavelengths

Krizo¹,

Cusumano²,

Bartell³

et al. 2008

SPIE Proceedings

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The Air Force Institute of Technology's Center for Directed Energy (AFIT/CDE) developed the High Energy Laser Endto-End Operational Simulation (HELEEOS) model in part to quantify the performance variance in laser propagation created by the natural environment during dynamic engagements. As such, HELEEOS includes a fast-calculating, first principles, worldwide surface-to-100 km, atmospheric propagation and characterization package. This package enables the creation of profiles of temperature, pressure, water vapor content, optical turbulence, atmospheric particulates and hydrometeors as they relate to line-by-line layer transmission, path and background radiance at wavelengths from the ultraviolet to radio frequencies. Physics-based cloud and precipitation characterizations are coupled with a probability of cloud free line-of-sight algorithm for all possible look angles. HELEEOS was developed under the sponsorship of the High Energy Laser Joint Technology Office.In the current paper an example of a unique high fidelity simulation of a bi-static, time-varying five band multispectral remote observation of laser energy delivered on a test object is presented. The multispectral example emphasizes atmospheric effects using HELEEOS, the interaction of the laser on target and the observed reflectance and subsequent hot spot generated. A model of a sensor suite located on the surface is included to collect the diffuse reflected in-band laser radiation and the emitted radiance of the hot spot in four separate and spatially offset MWIR and LWIR bands. Particular care is taken in modeling the bidirectional reflectivity distribution function (BRDF) of the laser/target interaction to account for both the coupling of energy into the target body and the changes in reflectance as a function of temperature. The architecture supports any platform-target-observer geometry, geographic location, season, and time of day; and it provides for correct contributions of the sky-earth background. The simulation accurately models the thermal response, kinetics, turbulence, base disturbance, diffraction, and signal-to-noise ratios.

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Section: Simulation Model Descriptionmentioning

confidence: 99%

A worldwide physics-based high spectral resolution atmospheric characterization and propagation package for UV to RF wavelengths

Krizo¹,

Cusumano²,

Bartell³

et al. 2008

SPIE Proceedings

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“…One of these codes, the High Energy Laser End-to-End Operational Simulation (HELEEOS) 1 , is perhaps the first DEW simulation package to fully incorporate a correlated, probabilistic climatological database. The infusion of such realistic atmospheric effects into the simulations allows HELEEOS to better assess variability/uncertainty in DEW system performance arising from spatial, spectral and temporal variations in operating conditions.…”

Section: Introductionmentioning

confidence: 99%

A first principles atmospheric propagation & characterization tool: the laser environmental effects definition and reference (LEEDR)

Fiorino¹,

Bartell²,

Krizo³

et al. 2008

Atmospheric Propagation of Electromagnetic Waves II

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The Air Force Institute of Technology Center for Directed Energy (AFIT/CDE) has developed a first principles atmospheric propagation and characterization model called the Laser Environmental Effects Definition and Reference or LEEDR. This package enables the creation of profiles of temperature, pressure, water vapor content, optical turbulence, and atmospheric particulates and hydrometeors as they relate to line-by-line layer extinction coefficient magnitude at wavelengths from the UV to the RF. Worldwide seasonal, diurnal, and geographical variability in these parameters is accessed from probability density function (PDF) databases using a variety of recently available resources to include the Extreme and Percentile Environmental Reference Tables (ExPERT), the Master Database for Optical Turbulence Research in Support of the Airborne Laser, and the Global Aerosol Data Set (GADS). GADS provides aerosol constituent number densities on a 5º x 5º grid worldwide. ExPERT mapping software allows the LEEDR operator to choose from specific site or regional upper air data to characterize correlated molecular absorption, aerosol absorption and scattering by percentile. The integration of the Surface Marine Gridded Climatology database, the Advanced Navy Aerosol Model (ANAM), and the Navy Surface Layer Optical Turbulence (NSLOT) model provides worldwide coverage over all ocean regions on a 1° x 1° grid. Molecular scattering is computed based on Rayleigh theory. Molecular absorption effects are computed for the top 13 absorbing species using line strength information from the HITRAN 2004 database in conjunction with a community standard molecular absorption continuum code. Aerosol scattering and absorption are computed with the Wiscombe Mie model. Each atmospheric particulate/hydrometeor is evaluated based on its wavelength-dependent forward and off-axis scattering characteristics and absorption effects on laser energy delivered at any wavelength from 0.355 µm to 8.6 m. LEEDR can also produce correlated optical turbulence profiles in percentile format. In addition, probability of cloud free line of sight (CFLOS) for hundreds of land sites worldwide is available in LEEDR. Effects of layers of fog, several types of rain and several types of water droplet and ice clouds can also be considered.In addition to describing some of the underlying theory to the LEEDR calculations, this paper presents graphical results for several different scenarios. These generic scenarios are meant to exemplify how LEEDR enables the physically realistic data capture of atmospheric effects on electromagnetic propagation.

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“…Its basic features have been previously described [1]. A key component of HELEEOS is a worldwide probabilistic model of spatial and temporal variations in atmospheric characteristics which has been described in detail [2,3,4].…”

Section: Heleeos Worldwide Seasonal Diurnal Atmospheric Modelmentioning

confidence: 99%

Worldwide uncertainty assessments of ladar and radar signal-to-noise ratio performance for diverse low altitude atmospheric environments

Fiorino¹

2010

J. Appl. Remote Sens

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Abstract:In this study of atmospheric effects on laser ranging and detection (ladar) and radar systems, the parameter space is explored using the Air Force Institute of Technology Center for Directed Energy's (AFIT/CDE) High Energy Laser End-to-End Operational Simulation (HELEEOS) parametric one-on-one engagement level model. The expected performance of ladar systems is assessed at a representative wavelength of 1.557 µm at a number of widely dispersed land and maritime locations worldwide. Radar system performance is assessed at 95 GHz and 250 GHz. Scenarios evaluated include both down looking oblique and vertical engagement geometries over ranges up to 3000 meters in which clear air aerosols and thin layers of fog, locally heavy rain, and low stratus cloud types are expected to occur. Seasonal and boundary layer variations are considered to determine optimum employment techniques to exploit or defeat the environmental conditions. Each atmospheric particulate/obscurant/hydrometeor is evaluated based on its wavelength-dependent forward and off-axis scattering characteristics and absorption effects on system interrogation. Results are presented in the form of worldwide plots of notional signal to noise ratio. The ladar and 95 GHz system types exhibit similar SNR performance for forward oblique clear air operation. 1.557 µm ladar performs well for vertical geometries in the presence of ground fog, but has no near-horizontal performance under such meteorological conditions. It also has no performance if low altitude stratus is present. 95 GHz performs well for both the fog and stratus layer cases, for both vertical and forward oblique geometries. The 250 GHz radar system is heavily impacted by water vapor absorption in all scenarios studied; however it is not as strongly affected by clouds and fog as the 1.557 µm ladar. Locally heavy rain will severely limit ladar system performance at these wavelengths. However, under heavy rain conditions ladar outperforms both radar systems.

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Methodology for comparing worldwide performance of diverse weight-constrained high energy laser systems

Cited by 27 publications

References 0 publications

A worldwide physics-based high spectral resolution atmospheric characterization and propagation package for UV to RF wavelengths

A worldwide physics-based high spectral resolution atmospheric characterization and propagation package for UV to RF wavelengths

A first principles atmospheric propagation & characterization tool: the laser environmental effects definition and reference (LEEDR)

Worldwide uncertainty assessments of ladar and radar signal-to-noise ratio performance for diverse low altitude atmospheric environments

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