A photonic true time delay processor for Global Positioning System (GPS) null steering

This paper presents a novel architecture for independently steering broadband nulls for phased array antennas. Measurements taken over a ten percent fractional bandwidth on a three-element proof-of-concept system shows a null depth of better than 40 dB uniform across the entire band in this laboratory setup. The architecture presented is best suited for small antenna array applications, for example GPS guided airborne munitions. In a fully integrated, optimized system, null depths of 50-70 dB or greater across a multi-gigahertz bandwidth are anticipated and the critical factors, which influence this performance, are examined.