A smart bullet is a bullet that is able to do something other than simply follow its given trajectory, such as turning, changing speed or sending data.
A patent for a guided bullet is held by Rolin F. Barrett Jr., of North Carolina, USA.
First efforts in this area were the 1980 NATO 'Copperhead' 155mm artillery shell project using mid flight adjustment onto target reflected laser guidance. This was shelved.
In 2008 the EXACTO program began under DARPA to develop a "fire and forget" smart sniper system including a guided smart bullet and improved scope. The exact technologies of this smart bullet have not been released. EXACTO was test fired in 2014 and results showing the bullet alter course to correct its path to its target were released.
In 2012 Sandia National Laboratories announced a self-guided bullet prototype that could track a target illuminated with a laser designator. The bullet is capable of updating its position 30 times a second and hitting targets over a mile away.
In mid-2016, Russia revealed it was developing a similar "smart bullet" designed to hit targets at a distance of up to 10 kilometres (6.2 mi).
One kind of smart bullet is a projectile that is capable of changing its course during flight. One use of this would be to enable soldiers to stay behind protective cover and shoot around corners. One implementation uses a spoiler and micro gyro to control the bullet.
Honeywell Aerospace has produced inertial measurement units based on MEMS and microelectronics technologies that it claims can survive the shock of being fired out of a gun.
Another smart bullet is one that can transmit data about the location into which it has been fired. A prototype has been created by researchers at the University of Florida in Gainesville, Florida, USA with funding from Lockheed Martin. The bullet (projectile) has a sensor inside of it that can send wireless data up to 70 meters.
Another smart bullet is one that self-destructs within a limited range. This would be used to minimize collateral damage of a bullet in case of a miss. For example, hunting near a populated area. This would involve either change in course into the ground, or near vaporization.