"Raytheon is testing a new laser-guided 155mm artillery shell which adds laser-designation to GPS guidance in order to provide more targeting options and better pinpoint targets on-the-move," reports DoD Buzz. It's called the Excalibur S.
Unlike expensive missiles, which require sophisticated avionics and propulsion systems, this is a comparatively cheap artillery shell which, instead of following a parabolic course to hit its target, it can change course in mid-flight, effectively flying to its target that can be 40km away.
The video below shows how the previous generation works, but this one wouldn't look that much different. It will be just more precise and cable of working in areas where GPS signals have been degraded, as well as moving targets.