Dr. Jagmit S. Sandhu Profile

Dr. Jagmit S. Sandhu

Optical Engineer at Jet Propulsion Lab

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Publications (6)

Proceedings Article | 16 September 2021 Paper

Polarimetric calibration of the multi-angle imager for aerosols (MAIA)

Gerard van Harten, Ab Davis, David Diner, Taryn Bailey, Emily Brageot, Carol Bruegge, Bruce Hancock, Leina Hutchinson, Kenneth Manatt, Saagar Patel, John Pearson, Brian Rheingans, Jagmit Sandhu, Jacob Shelton, Amanda Steffy, Daniel Warner, Thomas Werne

Proceedings Volume 11858, 118580I (2021) https://doi.org/10.1117/12.2600345

KEYWORDS: Calibration, Polarizers, Cameras, Polarimetry, Polarization, Modulation, Sensors, Aerosols, Remote sensing

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NASA’s Multi-Angle Imager for Aerosols (MAIA) mission, under development at the Jet Propulsion Laboratory, is designed to study the adverse health effects of different types of particulate air pollution. Planned for launch in late 2022 for a 3-year mission, the MAIA satellite instrument will focus on a selected set of metropolitan target areas, where air quality monitors and health data are available. Aerosol concentration and speciation are inferred from multi-angle measurements of backscattered sunlight in 14 spectral bands from 350-2200 nm, with bands near 442, 645 and 1040 nm measuring the degree (DoLP) and angle of linear polarization (AoLP) in addition to radiance. The pushbroom camera has a ~240-km cross-track field of view with a nadir resolution of ~200 m, and is mounted onto a biaxial gimbal to provide along-track view angles within ±60°, to extend the field of regard to ±48°, and to view the instrument’s onboard calibrator (OBC) and dark target. The OBC consists of a sunlit transmissive diffuser, followed by 12 polarizers at different orientations. MAIA’s polarimetry is implemented using miniature wiregrid polarizers on the focal plane array, and dual photoelastic modulators (PEMs) and achromatic quarter-wave plates to rapidly rotate the polarization. The resulting ~26-Hz intensity modulation encodes the linearly polarized and total radiance in each pixel, leaving the DoLP and AoLP insensitive to gain calibration. We report on the polarimetric calibration of the MAIA camera using a vacuum-compatible polarization state generator, consisting of a 1600W Xenon lamp, 12-inch integrating sphere, and rotating high-extinction polarizer. Mueller-matrix-based calibration coefficients for each detector pixel are derived from measurements at multiple polarizer angles, and are used to correct the measurements for instrumental polarization aberrations. Prior to flight, the calibrated MAIA camera is panned across the OBC to characterize its output, using uniform illumination with an irradiance similar to the Sun.

Proceedings Article | 1 August 2021 Presentation + Paper

Multi-Angle Imager for Aerosols (MAIA) spectral and radiometric calibration

Carol Bruegge, Ab Davis, Tarek Nagaty, Brian Rheingans, Jagmit Sandhu, David Scott, Gerard Van Harten

Proceedings Volume 11829, 118290T (2021) https://doi.org/10.1117/12.2594908

KEYWORDS: Cameras, Sensors, Calibration, Monochromators, Optical spheres, Spectral calibration

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Proceedings Article | 1 August 2021 Presentation + Paper

Geometric calibration of the Multi-Angle Imager for Aerosols (MAIA)

Jagmit Sandhu, Brian Rheingans, Ab Davis, Gerard van Harten, Carol Bruegge

Proceedings Volume 11829, 118290U (2021) https://doi.org/10.1117/12.2595016

KEYWORDS: Cameras, Sensors, Calibration, Polarimetry, Aerosols, Distortion

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Proceedings Article | 9 August 2016 Paper

Nanoradian ground-based astrometry, optical navigation, and artificial reference stars

Chengxing Zhai, Michael Shao, Abhijit Biswas, Todd Ely, Christopher Jacobs, Joseph Lazio, Tomas Martin-Mur, William Owen, Mike Rud, Navtej Saini, Jagmit Sandhu, Slava Turyshev, Thomas Werne

Proceedings Volume 9908, 99085B (2016) https://doi.org/10.1117/12.2233689

KEYWORDS: Stars, Space operations, Distortion, Space telescopes, Telescopes, Optical navigation, Adaptive optics, Refraction, Turbulence, Optical communications

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Proceedings Article | 22 July 2010 Paper

Results of the Guide-2 telescope testbed for the SIM Light Astrometric Observatory

I. Hahn, M. Weilert, J. Sandhu, X. Wang, R. Smythe, E. Hovland, F. Loya, J. Shields, D. Boussalis, N. Fathpour, B. Kang, A. Ahmed, G. Macala, F. Nicaise, M. Morales, F. Dekens, R. Goullioud

Proceedings Volume 7734, 77344H (2010) https://doi.org/10.1117/12.856531

KEYWORDS: Stars, Telescopes, Interferometers, Space telescopes, Charge-coupled devices, Mirrors, Metrology, Calibration, Sensors, Ferroelectric materials

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Proceedings Article | 28 July 2008 Paper

An introduction to the Guide-2 telescope testbed for the SIM Planet Quest Light mission

Inseob Hahn, J. Sandhu, M. Weilert, R. Smythe, F. Nicaise, B. Kang, F. Dekens, R. Goullioud

Proceedings Volume 7013, 70134W (2008) https://doi.org/10.1117/12.789358

KEYWORDS: Stars, Telescopes, Space telescopes, Interferometers, Sensors, Metrology, Planets, Optical testing, Interferometry, Michelson interferometers

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Showing 5 of 6 publications

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