Akins, Alex B., Alan B Tanner, Andreas Colliander, Nicole-Jeanne Schlegel, Kenza Boudad, and Igor Yanovsky, January 2025: A sparse synthetic aperture radiometer constellation concept for remote sensing of Antarctic ice sheet temperature. IEEE Transactions on Geoscience and Remote Sensing, 63, DOI:10.1109/TGRS.2025.3534466. Abstract
We present a concept for UHF/L band (0.5-2 GHz) remote sensing of Antarctic ice sheet internal temperature using a highly sparse synthetic aperture radiometer constellation. This concept leverages the relative stability of ice sheet thermal emission over long temporal periods to gradually assemble a collection of array baselines which are jointly transformed to develop large image facets. We formulate a calculation of minimum array complexity based on the desired sensitivity, spatial resolution, and time available for observations. We determine from this calculation that such a system can achieve 1-10 kilometer spatial resolution (significantly finer than the program of record) over monthly to yearly timescales with as few as 10-20 elements; even fewer elements are required for observing only the ice sheet center. The inverse problem of reconstructing image facets from mixed-pointing and mixed-configuration observations is posed using a Fourier domain data constraint with a total variational regularization in the image domain. This approach enables image formation from heterogeneous observations while mitigating artifacts. We present a notional constellation design for three satellites which could accomplish the necessary baseline sampling by rotating the phase and semi-major axis of spacecraft relative positions in planar circular orbits. We demonstrate image formation with observing system simulations leveraging predictions of Antarctica’s multi-wavelength brightness temperature computed from ice sheet thermomechanical and radiative transfer models.
