On-orbit calibration and performance of the EMIT imaging spectrometer
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- Data Release: USGS data release - Reflectance spectra collected August 16, 2022, at Smith Creek Valley, Nevada, with an ASD FieldSpecⓇ 4 Hi-Res NG spectrometer for calibration/validation of imaging spectrometer data
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Abstract
The Earth surface Mineral dust source InvesTigation (EMIT) is a remote visible to shortwave infrared (VSWIR) imaging spectrometer that has been operating onboard the International Space Station since July 2022. This article describes EMIT's on-orbit spectroradiometric calibration and validation. Accurate spectroscopy is vital to achieve consistent mapping results with orbital imaging spectrometers. EMIT takes a unique approach to this challenge, with just six optical elements, no shutter, and no onboard calibration systems. Its simple design focuses on uniformity and stability to enable vicarious spectroradiometric calibration. Our experiments demonstrate that this approach is successful, approaching the fidelity of manual field spectroscopy in some cases, and enabling new and more accurate products across diverse Earth science disciplines. EMIT achieves several notable firsts for an instrument of its class. It demonstrates successful on-orbit adjustments of Focal Plane Array (FPA) alignment with sub-micron precision. It offers spectral uniformity better than 98%. Optical artifacts in the measurement channels are at least three orders of magnitude below the primary solar-reflected surface signals. Its noise performance enables percent-level discrimination in the depths of mineral absorption features. In these aspects, EMIT satisfies the stringent performance needs for the next generation of VSWIR imaging spectrometers to observe the Earth's ecosystems, geology, and water resources.
Suggested Citation
Thompson, D.R., Green, R.O., Bradley, C., Brodrick, P.G., Mahowald, N., Ben-Dor, E., Bennett, M.R., Bernas, M., Carmon, N., Chadwick, K.D., Clark, R.N., Coleman, R.W., Cox, E., Diaz, E.L., Eastwood, M.L., Eckert, R., Ehlmann, B.L., Ginoux, P., Goncalves Ageitos, M., Grant, K., Guanter, L., Heller Pearlshtien, D., Helmlinger, M., Herzog, H., Hoefen, T.M., Huang, Y., Keebler, A., Kalashnikova, O., Keymeulen, D., Kokaly, R.F., Klose, M., Li, L., Lundeen, S., Meyer, J.M., Middleton, E., Miller, R.L., Mouroulis, P., Oaida, B., Obiso, V., Ochoa, F., Olson-Duvall, W., Okin, G.S., Painter, T.H., Perez Garcıa-Pando, C., Pollock, R., Realmuto, V.J., Shaw, L., Sullivan, P., Swayze, G.A., Thingvold, E., Thorpe, A.K., Vannan, S., Villarreal, C., Ung, C., Wilson, D.W., and Zandbergen, S., 2024, On-orbit calibration and performance of the EMIT imaging spectrometer: Remote Sensing of Environment, v. 303, 113986, 16 p., https://doi.org/10.1016/j.rse.2023.113986.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | On-orbit calibration and performance of the EMIT imaging spectrometer |
| Series title | Remote Sensing of Environment |
| DOI | 10.1016/j.rse.2023.113986 |
| Volume | 303 |
| Year Published | 2024 |
| Language | English |
| Publisher | Elsevier |
| Contributing office(s) | Geology, Geophysics, and Geochemistry Science Center |
| Description | 113986, 16 p. |