Leverage-Based Effective-Subspace Configuration of Equivalent Sources for Underwater Acoustic Radiation Prediction

The accuracy and efficiency of the equivalent source method (ESM) for underwater radiated-field prediction depend strongly on the position and number of the equivalent sources. The conventional uniform distribution (UD) is fixed before the field is observed, and the coherence-based optimum configuration (COC) ranks candidates by local pairwise correlations, blind to the singular directions the field excites. We propose the leverage-based effective-subspace configuration (LESC): it screens the singular directions the measured pressure excites, ranks candidates by leverage scores within that subspace, and prunes redundant sources by a coherence threshold, solving the strengths by cross-validated Tikhonov regularization. In free-space simulations of a baffled circular piston and a dual-hotspot planar source, LESC uses fewer, position-adaptive sources while cutting the 5000 Hz error by 73–83% compared with UD and by 73–74% against COC, and maintains an error of 2.33% at 6300 Hz, where UD and COC degrade sharply, at one-third to one-half of COC’s configuration cost. An ablation identifies the effective singular-direction screening as the decisive ingredient. The ordering is reproduced at matched source counts and under colored and spatially correlated noise, reversing only where the source count is small relative to the excited-direction count. The study is confined to free-space radiation from planar sources, within which these advantages are established.