A Variational Adjoint Approach on Wide-Angle Parabolic Equation for Refractivity Inversion

Uygar Karabaş (1, 2) , Youssef Diouane (2) , Rémi Douvenot (1)

1 ENAC - Ecole Nationale de l'Aviation Civile
2 ISAE-SUPAERO - Institut Supérieur de l'Aéronautique et de l'Espace

Radar systems performance under anomalous propagation conditions can be predicted if the atmosphere is properly known. This paper introduces a tomographic approach to estimate refractivity in the troposphere with an adjoint-based inversion method. A new adjoint model is developed for the two-dimensional wide-angle parabolic equation using variational adjoint approach, to invert refractivity from phaseless data measured with an array of radio receivers in open-sea environment. The obtained adjoint model is validated considering propagation through range-independent medium over flat perfectly-electric-conducting surface at horizontal polarization. The ill-posedness of the regarded inverse problem is shown with the optimization landscapes. The parametric study indicates the potential use of this method as a refractivity gradient retrieval system under certain circumstances.

Mots clés: Refractivity inversion; inverse problem; wide-angle parabolic equation; adjoint model

Domaines: Sciences de l'ingénieur [physics]; Traitement du signal et de l'image [eess.SP]

Uygar Karabaş, Youssef Diouane, Rémi Douvenot. A Variational Adjoint Approach on Wide-Angle Parabolic Equation for Refractivity Inversion. IEEE Transactions on Antennas and Propagation, 2021, 69 (8), pp.4861-4870. ⟨10.1109/TAP.2021.3060073⟩. ⟨hal-03156207⟩