Long-wave infrared imaging spectroscopy from small satellite and UAV platforms

Transcription

1 Long-wave infrared imaging spectroscopy from small satellite and UAV platforms Robert Wright, Paul Lucey, Sarah Crites, Mark Wood, Harold Garbeil, Eric Pilger Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Mānoa

2 Overview Thermal infrared (3-5 µm and 8-14 µm) imaging spectroscopy allows you to quantify the chemical composition of solid and gaseous targets remotely, as well as their thermophysical characteristics Imaging interferometry has the potential to characterize these targets at high spectral resolution, with high signal-to-noise HIGP has active programs aimed at making such remote sensing instruments small enough, light enough, and with low enough power requirements, to be flown on micro-satellites and UAVs Methane leak, Los Angeles CH 4 S i O 2 Dust cloud, Iraq HIGP-developed TIRCIS instrument

3 Small-sat/UAV compatible sensors built at HIGP Thermal Infrared Compact Imaging Spectrometer (TIRCIS) Space Ultra-Compact Hyperspectral Imager (SUCHI) Thermal Hyperspectral Imager (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, 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

4 Thermal Infra-Red Compact Imaging Spectrometer (TIRCIS) Funded by NASA ( ) 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

5 Spectral imaging using a Fabry-Perot interferometer Calibration Fabry-Perot interferometer Lenses Uncooled microbolometer

6 TIRCIS instrument design Uncooled microbolometer Secondary radiometric calibration and flat-field correction Interferometer Lenses Structure Primary radiometric calibration Electronics

7 TIRCIS spatial resolution: 120 m ground resolution from 500 km 0.2 kg 2.4 kg

8 TIRCIS spectral resolution: 15 to 90 wavebands between 8-14 µm 0.1 kg i) Interferometer #1 = 44 cm -1 ~ 15 samples between 8-14 µm ii) Interferometer #2 = 8.7 cm -1 ~60 samples between 8-14 µm iii) Interferometer #3 = 6.5 cm -1 ~90 samples between 8-14 µm

9 Wedge angle equates to samples in the interferogram 5 mrad slope = 44 cm mrad slope = 8.7 cm -1

10 TIRCIS structure: stress and deformation Mode shape 1: Hz Mode shape 2: Hz ASD vs frequency for 55 kg micro-satellite (derived from NASA GEVS-SE, RevA, 1996) Deformation Maximum displacement = 0.05 mm (primary calibrator) and 0.02 mm for optical elements (camera) Stress Maximum = 5000 psi (yield strength of material = 8000 psi)

11 TIRCIS performance model: signal-to-noise predictions

12 Instrument test facilities: blackbody standards Two 8 aperture NIST-traceable blackbody calibration standards (-40 C to 120 C)

13 Instrument test facilities: collimator/target projector Collimator, target projector (with spectral calibration capability)

14 Instrument test facilities: high resolution FTIR spectrometer Design and Prototypes Model 102 FTIR spectrometer 4 cm -1 spectral resolution 2-14 µm spectral range

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16 120 m GRE from 500 km 60 channels (8-14 µm) SNR ~ :1 Mass = 5 kg Peak power = 20 W Dimensions = 28 cm 36 cm 56 cm TIRCIS instrument summary

17 Space Ultra-Compact Hyperspectral Imager (SUCHI) Design funded by NASA ( ) 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

18 SUCHI instrument design

19 Onboard calibration shutters

20 Sealed vessel houses non-space-qualified components

21 SUCHI electronics, designed and fabricated in house

22 SUCHI in the cleanrooms

23 SUCHI undergoing vibration testing

24 Thermal-Vacuum test chamber

25 SUCHI undergoing T-VAC testing

26 SUCHI instrument summary 250 m GRE from 500 km 20 channels (8-14 µm) SNR ~ :1 Mass = 10 kg Peak power = 7 W Dimensions = 10 cm 11 cm 36 cm

27 SUCHI was launched onboard ORS-4 in October 2015

28 Thermal Hyperspectral Imager (THI)

29 Calibrated gas measurements with THI

30 Field gas measurements with THI

31 Summary Thermal Infrared Compact Imaging Spectrometer (TIRCIS) Space Ultra-Compact Hyperspectral Imager (SUCHI) Thermal Hyperspectral Imager (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