Hazard Detection Analysis for a Forward-Looking Interferometer

West, Leanne L.; Gimmestad, Gary G.; Herkert, R.M.; Smith, William L.; Kireev, Stanislav; Daniels, Taumi S.; Cornman, Larry; Sharman, Bob; Weekley, A.; Perram, Glen P.; Gross, Kevin C.; Smith, Gregory G.; Feltz, Wayne F.; Taylor, Joe K.; Olson, E. P.

doi:10.2514/6.2009-3635

Cited by 5 publications

(3 citation statements)

References 5 publications

(4 reference statements)

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“…All of these instruments are either looking upwards or downwards and for the good reason that investigating infrared radiation works well when either the feature of interest is emitting (against a cold background) or absorbing (against a warm background). Gimmestad et al and colleagues [3,16,17] used an airborne interferometric instrument to look in the forward direction in studies of atmospheric turbulence. The problem of viewing the atmosphere along a horizontal path or towards the horizon comprises both emission and absorption processes and is thus complicated and can lead to ambiguity.…”

Section: Introductionmentioning

confidence: 99%

Detection and Avoidance of Atmospheric Aviation Hazards Using Infrared Spectroscopic Imaging

Prata

2020

Remote Sensing

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Atmospheric aviation hazards due to turbulence, poor visibility, high-altitude ice crystals and volcanic ash and gases are known problems for aviation and can cause both economic damage to engines and airframes as well as having the potential to cause the engines to stall in flight with possible loss of the aircraft. Current space- and ground-based assets allow observations of some of these hazards and their detection and movement can be forecast using modern computer weather forecasting and dispersion models. These largely strategic resources have proved very valuable but somewhat limited in the tactical sense, where commercial aviation must make rapid decisions in order to avoid an undetected or un-forecast hazardous cloud or atmospheric condition. Here we investigate the use of multi-spectral (two channels or more) infrared imaging from an aircraft perspective, and show that it is possible to use this information to provide tactical awareness tools for use by aviators and other stakeholders. This study has a strong focus on volcanic ash as an aviation hazard but also includes applications to some forms of clear air turbulence (CAT), to high-altitude ice crystals (HAIC) and windblown desert dust. For volcanic ash detection, the research shows that current two-channel satellite-based infrared techniques provide acceptable discrimination and quantification, but two-channel infrared imaging airborne solutions have significant drawbacks. Because of the limitation of two-channel methods, infrared spectroscopic techniques are investigated and it is shown they can significantly reduce the confusion caused by meteorological hydrometeors and potentially provide information on other atmospheric hazards to aviation, such as HAIC and some forms of turbulence. Not only are these findings important for on-going efforts to incorporate IR imaging onto commercial aircraft, but they also have relevance to the increasing use of drones for hazard detection, research and monitoring. Uncooled infrared bolometric imaging cameras with spectroscopic capabilities are available and we describe one such system for use on airborne platforms.

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Section: Introductionmentioning

confidence: 99%

Detection and Avoidance of Atmospheric Aviation Hazards Using Infrared Spectroscopic Imaging

Prata

2020

Remote Sensing

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“…This research was continued with simulations of clear air turbulence, runway surface state, volcanic ash, icing, wind shear, and wake vortices and results of field deployments with two different IR FTS instruments. [2][3][4] Additional efforts to characterize imaging IR spectrometers to detect wake vortices was conducted. 5,6 In these studies, both long wave IR (LWIR, 700 to 1300 cm −1 ), midwave IR (MWIR, 2000 to 3300 cm −1 ) spectrometer bands were investigated.…”

Section: Introductionmentioning

confidence: 99%

Simulation of wake vortex radiometric detection via jet exhaust proxy

Daniels

2015

Next-Generation Spectroscopic Technologies VIII

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This paper describes an analysis of the potential of an airborne hyperspectral imaging IR instrument to infer wake vortices via turbine jet exhaust as a proxy. The goal was to determine the requirements for an imaging spectrometer or radiometer to effectively detect the exhaust plume, and by inference, the location of the wake vortices. The effort examines the gas spectroscopy of the various major constituents of turbine jet exhaust and their contributions to the modeled detectable radiance. Initially, a theoretical analysis of wake vortex proxy detection by thermal radiation was realized in a series of simulations. The first stage used the SLAB plume model to simulate turbine jet exhaust plume characteristics, including exhaust gas transport dynamics and concentrations. The second stage used these plume characteristics as input to the Line By Line Radiative Transfer Model (LBLRTM) to simulate responses from both an imaging IR hyperspectral spectrometer or radiometer. These numerical simulations generated thermal imagery that was compared with previously reported wake vortex temperature data. This research is a continuation of an effort to specify the requirements for an imaging IR spectrometer or radiometer to make wake vortex measurements. Results of the two-stage simulation will be reported, including instrument specifications for wake vortex thermal detection. These results will be compared with previously reported results for IR imaging spectrometer performance.

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“…[1][2][3] The ability of the FLI to provide estimates of the range to in-flight hazards was also investigated, with the result that both detection and ranging are enabled by the high spectral resolution provided by the FTS. A sufficient infrared spectral signature appeared to be associated with the hazards to enable detection and/or mitigation of all of them, although detection of CAT at relevant ranges may also require that the FLI have high temperature resolution, dependent on a good signalto-noise ratio.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of a Forward Looking Interferometer for Detection of Clear Air Turbulence Due to Mountain Waves

Schaffner

Daniels

West

et al. 2012

4th AIAA Atmospheric and Space Environments Conference

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The Forward-Looking Interferometer (FLI) is an airborne sensor concept for detection and estimation of potential atmospheric hazards to aircraft. To be commercially viable such a sensor should address multiple hazards to justify the costs of development, certification, installation, training, and maintenance. The FLI concept is based on high-resolution infrared Fourier Transform Spectrometry (FTS) technologies that have been developed for satellite remote sensing. These technologies have also been applied to the detection of aerosols and gases for other purposes. The FLI is being evaluated for its potential to address multiple hazards, during all phases of flight, including clear air turbulence (CAT), volcanic ash, wake vortices, low slant range visibility, dry wind shear, and icing. In addition, the FLI is being evaluated for its potential to detect hazardous runway conditions during landing, such as wet or icy asphalt or concrete. The validation of model-based instrument and hazard simulation results is accomplished by comparing predicted performance against empirical data. Models for FLI measurables for mountain wave turbulence were developed during the previous phases of the project. Prior to the field campaign, these models were used to predict what the sensors should have been able to detect, based on expected instrument performance. After the data collection activities, the empirical data was used to update and validate the existing models. This iterative process was employed during the course of the project as new empirical results became available. Previous research programs, focused on forward-looking airborne sensors such as Doppler radars and lidars to detect and forecast turbulence, have produced many tools for analysis, modeling, and simulation. Following on the methods used in the airborne radar turbulence detection problem, relationships between the statistics of an atmospheric disturbance (such as the temperature field) and those of the https://ntrs.nasa.gov/search.jsp?R=20120011814 2018-05-10T00:12:31+00:00ZAmerican Institute of Aeronautics and Astronautics 2 sensor measurements (the spectral radiance) will be developed. In the mountain lee wave data collected in the previous FLI project, the data showed a damped, periodic mountain wave structure. The wave data itself will be of use in forecast and nowcast turbulence products such as the Graphical Turbulence Guidance (GTG) and Graphical Turbulence Guidance Nowcast (GTG-N) products. Determining how turbulence hazard estimates can be derived from FLI measurements will require further investigation.

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Hazard Detection Analysis for a Forward-Looking Interferometer

Cited by 5 publications

References 5 publications

Detection and Avoidance of Atmospheric Aviation Hazards Using Infrared Spectroscopic Imaging

Detection and Avoidance of Atmospheric Aviation Hazards Using Infrared Spectroscopic Imaging

Simulation of wake vortex radiometric detection via jet exhaust proxy

Experimental Validation of a Forward Looking Interferometer for Detection of Clear Air Turbulence Due to Mountain Waves

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