A Posteriori De-aliasing of Ocean Tide Error in Future Double-Pair Satellite Gravity Missions
Ocean tides cause notable aliasing errors in the gravity field from single pair space-borne gravimetry missions like GRACE. Several studies into future gravity missions have shown that constellations with two or more GRACE-like tandems lead to a significant reduction of aliasing error from all kinds of high-frequency signal sources. Despite such reduction, tidal aliasing will remain an error source. We here investigate the efficiency of tidal error de-aliasing in the post-processing mode for such future double-pair missions. To that purpose, we analyze how a certain satellite mission samples each tidal constituent. Given the repeat orbit patterns and the observation time span, we examine and model the alias periods and amplitudes constituent by constituent based on data-driven analysis. Results show that a double-pair formation has indeed better de-aliasing properties than a single-pair formation in terms of distribution and amplitude of ocean tide aliasing error. After least-squares (LS) spectral estimation of the tidal aliases at the derived alias periods, the aliasing error is reduced significantly.
KeywordsDe-aliasing Future mission Ocean tides Satellite gravity
This research was motivated by ESA project “Assessment of Satellite Constellations for Monitoring the Variations in Earth’s Gravity (SC4MGV)”. ESA-ESTEC is gratefully acknowledged for funding the project under Contract No.4000108663/13/NL/MV. The first author acknowledges the Chinese Scholarship Council (CSC) for supporting her PhD study.
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