Corrosion and other imperfections in metal structures exhibit Passive Inter Modulation (PIM) emissions when exposed to multi-tone Radio Frequency (RF) emissions. PIM processes generally have a signature based on the physical processes that generate them, but their use in standoff detection and corrosion characterization pose significant challenges. IAI and collaborator, Southwest Research Institute (SwRI), will develop PIMCAL, the Passive Inter Modulation for Corrosion Assessment and Localization system, that uses PIM emissions to detect, locate, and monitor galvanic corrosion on metal structures of interest to the Missile Defense Agency (MDA). The key innovation is utilizing multiple, coordinated transmitters to focus on multi-frequency RF signatures in the unlicensed 433, 900, and 2400 MHz bands at efficient coupling points on each structure under test and create standing waves with associated high current densities. PIMCAL’s key components include an ultra-high dynamic range PIM receiver that enables operation over multiple bands and tone separations. This state-of-the-art, highly linear receiver architecture with greater than 160 dB of dynamic range is combined with a sophisticated signal coding to detect, localize, characterize, and monitor galvanic corrosion on land- and ship-based structures like radars and antenna masts. PIMCAL will leverage proven technologies for receiver detection and localization sponsored by ARMY CERDEC, and coherence of multiple, spatially separated transmitters at a target location developed under DARPA funding. A robust library of galvanic corrosion signatures will be developed using well-characterized test samples and measurements. In addition to galvanic corrosion monitoring and localization in metal structures, PIMCAL will also provide a power characterization tool for PIM effects on highly sensitive RF receivers for RADAR, SIGINT, and other communications.