Definition:
~ by providing images of terrain, in both visible and infrared wavelengths, and often enabling laser range finding with regard to landmarks,
~ optronic sensors enhance basic inertial navigation by enabling metric quality updates, i.e. better than GPS (but less continuous)
~ good navigating also requires a smooth and continuous "guide rail", provided by inertial navigation, around which everything else revolves
~ once you have exploited hybridized inertial navigation to the best possible advantage
~ through radio-frequency means (GPS, radioaltimeter + terrain contour matching, etc) to achieve decametric quality navigation,
~ final touch, which offers a 2 to 5 enhancement factor, can only be provided by optronics
~ this enables updates with regard to visible or thermal markers , a typical example is AASM air-to-ground guided weapon
~ use of optronics for navigation largely involves correlating images
~ vehicle is equipped with an "imager" which observes surrounding landscape (usually in front of it and sometimes below)
~ mission planning workstation first prepares a spatial representation of images vehicle should expect to see,
~ according to its supposed position at a particular point and these are then loaded onto on-board computer
~ computer then scrolls through the current position possibilities in order
~ to find the best match between image viewed and set of possible images stored in memory
~ when a high correlation is detected, any position discrepancies are put down to a probable navigation error
~ this procedure is similar to terrain contour matching navigation and
~ image processing involved is comparable to that used to recognize fingerprints, which are like a miniature landscape after all