Ultra-precision angle measurement sensors have been developed for a large number of high-performance commercial, industrial and military applications. The sensors are designed to answer the general questions “where am I?” or “where is that?” in indoor and outdoor environments. These angle measurement sensors are composed of ultra-precision optical modules, specialized coding masks, analog optical detectors and digital processing. We call the general technology “Angle Coding” and the particular products Accu-Arc sensors. In comparison to all previous systems, Accu-Arc sensors are composed of small, lightweight, monolithic optical components that have a wide field of view and an intrinsically rugged package, have no moving parts, use low complexity electronics enabling low power and high speed, and use modern ultra-precision optical fabrication and assembly techniques for the lowest possible production costs combined with the highest possible performance.