They first gained public recognition during Operation Desert Storm when they were used by the US against Iraq.
Early smart bombs used laser guidance, relying on the target being illuminated by a "target designator" on the ground, but were not usable in poor weather conditions where the target illumination could not be seen, or where it was not possible to get a target designator near to the target.
Modern smart bombs use satellite navigation systems, specifically the United States' GPS system. This offers improved accuracy compared to laser systems, and can operate in all weather conditions, without any need for ground support.
The precision of these weapons is dependent both on the precision of the measurement system used for location determination and the precision in setting the coordinates of the target. The latter critically depends on intelligence information not all of which is accurate.
The creation of precision-guided munitions resulted in the renaming of older bombs as "gravity bombs".
See also:
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