Modern anti-radiation missiles face an increasingly complex target signal environment which, in its total scope, includes active electronic countermeasures such as advanced waveforms, low spectral power density, and integration into a tactical (or strategic) air defense system such that the weapons associated radars minimize "uptime." Effective integration of an air defense system allows the fire control radars to remain off the air, except during actual missile flyout, having been passed the necessary target location/ track data prom other assets within the total air defense system. A fundamental enhancement to be provided for the anti-radiation missile receiving segment is a significant increase in sensitivity in order to detect target antenna sidelobes of all orders (including backlobes). Ideally, enhancement of arm receiver sensitivity can be effected by a simple retrofit of existing systems, thus recovering the very significant "sunk costs in existing missiles. Processing Research Incorporated (PRI) has proposed a sensitivity enhancement technique based upon a unique (patents pending) approach based on its proprietary correlation phase detector technique that is directly usable as a simple, low cost retrofit of existing missile systems and can also provide equivalent performance enhancement for advanced arm receiver systems designed to counter other target attributes such as advanced waveforms and multiple or expanded frequency usage. In many cases, direct substitution of the PRI coherent processor for the existing phase detector/integrator circuit element can result in over 1,000:1 improvement in arm receiver sensitivity. Full realization of angular accuracy improvements afforded by a correlation processor will require increasing the arm receiver antenna pair spacing.
