Simulated small-signal differential response (interaction matrix measurement) of the PWFS in the four ESC measurement maps for 3 aberrations: tilt (left), spherical (center), and higher frequency Karhunen–Loëve #103 (right). Top row: the system is perfectly aligned and differential signals in Z_Glob and F_Glob are zero. Bottom row: exaggerated misalignment case (up to ≈5% of pupil diameter for each quadrant), illustrating how information is now spread across all four X,  Y,  Z,  F_Glob ESC measurements.