MightySat II.1: an optical design and performance update

Otten, Leonard John; Meigs, Andrew D.; Portigal, Frederick P.; Jones, Bernard Al; Sellar, R. Glenn; Fronterhouse, Donald C.; Rafert, Bruce; O'Hair, John R.; Turner, Theodore S.

doi:10.1117/12.265455

“…The optical system was designed to meet the system requirements in Table 1, in thermal conditions of -20 to +20 degrees C, with the temperature band being determined by changes in the index of refraction of the various refractive materials. 5 This temperature range is maintained through a cold biased design that uses thermal isolation, blankets, and heaters. Thermal vacuum testing and on-orbit results have verified the ability to maintain the temperature range.…”

Section: Lifetime Statisticsmentioning

confidence: 99%

MightySat II.1 Hyperspectral Imager: Summary of On-Orbit Performance

Yarbrough¹,

Caudill²,

Kouba³

et al. 2002

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The primary payload on a small-satellite, the Air Force Research Laboratory's MightySat II.1, is a spatially modulated Fourier Transform Hyperspectral Imager (FTHSI) designed for terrain classification. The heart of this instrument is a solid block Sagnac interferometer with 85cm -1 spectral resolution over the 475nm to 1050nm wavelength range and 30m spatial resolution. Coupled with this hyperspectral imager is a Quad-C40 card, used for on-orbit processing. The satellite was launched on 19 July 2000 into a 575km, 97.8 degree inclination, sun-synchronous orbit. The hyperspectral imager collected its first data set on 1 August 2000. To the best of our knowledge, the MightySat II.1 sensor is the first true hyperspectral earth-viewing imager to be successfully operated in space. The paper will describe the satellite and instrument, pre-launch calibration results, on-orbit performance, and the calibration process used to characterize the sensor. We will also present data on the projected lifetime of the sensor along with samples of the types of data being collected. BACKGROUND: WHY HYPERSPECTRAL IN SPACEImagery from space has been limited to black and white high resolution and multispectral imagery. Black and white imagery cannot differentiate between types of vegetation or road materials. Multispectral imagery can differentiate these objects, but at a limited number of bands. To enhance the multispectral capability additional spectral bands need to be imaged. Hyperspectral imagery expands the number of spectral bands that are collected.Previously, hyperspectral imagers have been mounted in light aircraft. These imagers are limited by flying conditions and airspace boundaries (i.e. national borders and restricted flight areas). When the imager is space-based, however, the airspace Invited Paper

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“…During the end of 1980s and the beginning of 1990s, along with the development of the aerospace remote sensing technology and the CCD manufacturing technology, spatially modulated imaging Fourier Transform spectroscopy emerged and sprung up [1][2][3][4][5][6] . Because of its advantages of acquiring two dimensional spatially information and one dimensional spectra information simultaneously, high throughput utilization ratio, high signal-noise ratio, and so forth, this kind of technology soon became a developing focus.…”

Section: Introductionmentioning

confidence: 99%

Effect of Platform Attitude Stability on Image Quality of Spatially Modulated Imaging Fourier Transform Spectrometer

Jing

¹

,

Wei

²

,

Yuan

³

2010

2010 Third International Symposium on Information Science and Engineering

1

0

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The data acquired by the spatially modulated imaging Fourier Transform spectrometer(SMIFTS) contain one dimensional spatial information, one dimensional interference information, and one dimensional pushbroom scanning spatial information. This kind of spectrometer theoretically requires that flying platform keeps uniform moving velocity and steady attitude in the imaging mode, as well as the imaging motion in each two neighboring interferograms is one array of pixels. The unsteadiness of platform would not only cause problems such as distortion, mixed pixels and lower signal-noise ratio on acquired spatial images, but also produce deviation and decadence of interferograms away from ideal ones, bringing the distortion of real spectra. The abnormal image motion model between satellite attitude and the data acquired by SMIFTS is built based on the theory that projection center of a sensor, an image point and an object on the ground are in the same line. This paper calculates the image motions between different frames, assuming that the pitch angle and yaw angle are same, And moreover, analyzes the effect of the attitude steadiness on the data quality of SMIFTS. The results show that, pitch angle bringing distortion of neighboring interferograms in alongorbit directions has most serious effect, the image gradient decrease obviouly and the discrepancy between interferogram and spectra is bigger; yaw angle bringing the relative rotation of neighboring interferograms has the less serious effect on images and spectra. To get the real spectra of the object, we should take some measures to correct it.

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“…5 This temperature range is maintained through a cold biased design that uses thermal isolation, blankets, and heaters. Thermal vacuum testing and on-orbit results have verified the ability to maintain the temperature range.…”

Section: Lifetime Statisticsmentioning

confidence: 99%

MightySat II.1 hyperspectral imager: summary of on-orbit performance

Yarbrough

¹

,

Caudill

²

,

Kouba

³

et al. 2002

Self Cite

View full text Add to dashboard Cite

The primary payload on a small-satellite, the Air Force Research Laboratory's MightySat II.1, is a spatially modulated Fourier Transform Hyperspectral Imager (FTHSI) designed for terrain classification. The heart of this instrument is a solid block Sagnac interferometer with 85cm -1 spectral resolution over the 475nm to 1050nm wavelength range and 30m spatial resolution. Coupled with this hyperspectral imager is a Quad-C40 card, used for on-orbit processing. The satellite was launched on 19 July 2000 into a 575km, 97.8 degree inclination, sun-synchronous orbit. The hyperspectral imager collected its first data set on 1 August 2000. To the best of our knowledge, the MightySat II.1 sensor is the first true hyperspectral earth-viewing imager to be successfully operated in space. The paper will describe the satellite and instrument, pre-launch calibration results, on-orbit performance, and the calibration process used to characterize the sensor. We will also present data on the projected lifetime of the sensor along with samples of the types of data being collected. BACKGROUND: WHY HYPERSPECTRAL IN SPACEImagery from space has been limited to black and white high resolution and multispectral imagery. Black and white imagery cannot differentiate between types of vegetation or road materials. Multispectral imagery can differentiate these objects, but at a limited number of bands. To enhance the multispectral capability additional spectral bands need to be imaged. Hyperspectral imagery expands the number of spectral bands that are collected.Previously, hyperspectral imagers have been mounted in light aircraft. These imagers are limited by flying conditions and airspace boundaries (i.e. national borders and restricted flight areas). When the imager is space-based, however, the airspace Invited Paper

show abstract

MightySat II.1: an optical design and performance update

Cited by 5 publications

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MightySat II.1 Hyperspectral Imager: Summary of On-Orbit Performance

MightySat II.1 Hyperspectral Imager: Summary of On-Orbit Performance

Effect of Platform Attitude Stability on Image Quality of Spatially Modulated Imaging Fourier Transform Spectrometer

MightySat II.1 hyperspectral imager: summary of on-orbit performance

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