A system and method for real-time in-situ calibration of an Active Electronically Scanned Array (AESA) utilizes an S-parameter matrix-based EM transfer function between an end fire, unobtrusive, near field probe radiating element to minimize AESA look angle blockage. A sniffer probe is integrated in the AESA aperture of mechanical mounting frame or embedded with the AESA aperture structure. Hadamard orthogonal coding is utilized to simultaneously energize AESA elements.