Long-wave infrared imaging spectroscopy from small satellite ......Long-wave infrared imaging...
Transcript of Long-wave infrared imaging spectroscopy from small satellite ......Long-wave infrared imaging...
Long-wave infrared imaging spectroscopy from small satellite and UAV platformsRobert Wright, Paul Lucey, Sarah Crites, Mark Wood, Harold Garbeil, Eric Pilger
Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Mānoa
Overview• Thermal infrared (3-5 µm
and 8-14 µm) imagingspectroscopy allows you toquantify the chemicalcomposition of solid andgaseous targets remotely, aswell as their thermo-physical characteristics
• Imaging interferometry hasthe potential to characterizethese targets at highspectral resolution, withhigh signal-to-noise
• HIGP has active programsaimed at making suchremote sensing instrumentssmall enough, light enough,and with low enough powerrequirements, to be flownon micro-satellites and UAVs
Methane leak, Los Angeles Dust cloud, Iraq
HIGP-developed TIRCIS instrument
CH4SiO2
• HIGP designs, builds and tests thermal infrared imaging spectrometers, with a focus on high spectral resolution and high sensitivity (signal-to-noise)
• In line with the growing importance of small satellites and UAV platforms, these instruments are designed to be compact, low mass, with modest power requirements
• To satisfy these (seemingly) mutually exclusive goals we have focused on two key technologies:
• Uncooled microbolometer detector arrays to detecting the light• An Interferometric approach to resolving the spectral composition of the light
Small-sat/UAV compatible sensors built at HIGP
Thermal Infrared Compact Imaging Spectrometer (TIRCIS)
Space Ultra-Compact Hyperspectral Imager (SUCHI)
Thermal Hyperspectral Imager (THI)
Thermal Infra-Red Compact Imaging Spectrometer(TIRCIS)
• Funded by NASA (2014-2017)• Goal is to design, build and test a prototype
for a small-satellite compliant thermal infrared imaging spectrometer
• Advance from TRL 4 to TRL 6
Calibration
Uncooled microbolometer
Fabry-Perot interferometer
Lenses
Spectral imaging using a Fabry-Perot interferometer
Interferometer
Uncooled microbolometer
Primary radiometric calibration
Secondary radiometric calibration
and flat-field correction
Lenses
Electronics
Structure
TIRCIS instrument design
2.4 kg
0.2 kg
TIRCIS spatial resolution: 120 m ground resolution from 500 km
i) Interferometer #1 = 44 cm-1 ~ 15 samples between 8-14 µmii) Interferometer #2 = 8.7 cm-1 ~60 samples between 8-14 µmiii) Interferometer #3 = 6.5 cm-1 ~90 samples between 8-14 µm
0.1 kg
TIRCIS spectral resolution: 15 to 90 wavebands between 8-14 µm
Wedge angle equates to samples in the interferogram
5 mrad slope = 44 cm-1 15 mrad slope = 8.7 cm-1
TIRCIS structure: stress and deformation
StressMaximum = 5000 psi (yield strength of material = 8000 psi)
DeformationMaximum displacement = 0.05 mm (primary calibrator) and 0.02
mm for optical elements (camera)
Mode shape 1: 222.98 Hz Mode shape 2: 352.48 Hz
ASD vs frequency for 55 kg micro-satellite(derived from NASA GEVS-SE, RevA, 1996)
TIRCIS performance model: signal-to-noise predictions
Two 8” aperture NIST-traceable blackbody calibration standards (-40 °C to 120 °C)
Instrument test facilities: blackbody standards
Instrument test facilities: collimator/target projector
Collimator, target projector (with spectral calibration capability)
Instrument test facilities: high resolution FTIR spectrometer
Design and Prototypes Model 102 FTIR spectrometer• 4 cm-1 spectral resolution• 2-14 µm spectral range
120 m GRE from 500 km60 channels (8-14 µm)SNR ~200-400:1Mass = 5 kgPeak power = 20 WDimensions = 28 cm × 36 cm × 56 cm
TIRCIS instrument summary
Space Ultra-Compact Hyperspectral Imager (SUCHI)
• Design funded by NASA (2010-2014)• Goal was to design, build and test a flight
unit for a thermal infrared imaging spectrometer, as the primary payload for the ORS-4 mission
SUCHI instrument design
Onboard calibration shutters
Sealed vessel houses non-space-qualified components
SUCHI electronics, designed and fabricated in house
SUCHI in the cleanrooms
SUCHI undergoing vibration testing
Thermal-Vacuum test chamber
SUCHI undergoing T-VAC testing
SUCHI instrument summary
250 m GRE from 500 km20 channels (8-14 µm)SNR ~200-400:1Mass = 10 kgPeak power = 7 WDimensions = 10 cm × 11 cm × 36 cm
SUCHI was launched onboard ORS-4 in October 2015
Thermal Hyperspectral Imager (THI)
Calibrated gas measurements with THI
Field gas measurements with THI
• HIGP designs, builds and tests thermal infrared imaging spectrometers, with a focus on high spectral resolution and high sensitivity (signal-to-noise)
• In line with the growing importance of small satellites and UAV platforms, these instruments are designed to be compact, low mass, and with modest power requirements
• HIGP has facilities to design, fabricate and test the instruments in house
Thermal Infrared Compact Imaging Spectrometer (TIRCIS)
Space Ultra-Compact Hyperspectral Imager (SUCHI)
Thermal Hyperspectral Imager (THI)
Summary