Boeing, in developing the second generation of the Small Diameter Bomb, which adds a tri-mode seeker to the concept of the existing GPS/INS SDB, recognized that the hard part of designing a precision weapon is the guidance. The airframe and warhead are usually rather straightforward. And they also had the bright idea to strap a rocket booster to the back of the SDB II, and introduce a ground launched version.
Even better, they were able to use the existing booster from original style rockets of the long serving M270 MLRS. That keeps costs down. Plus, the MLRS system’s existing infrastructure reduces costs and training needed.
While the current GPS/INS guided unitary warhead GMLRS system is fine, it is also unable to accurately target moving targets. The SDB II was designed to strike moving targets. That’s going to increase the ability to hold at risk enemy high value/high payoff targets such as air defense systems.
We also wonder how long it will be until someone discusses the potential for coastal defense, or even a ship launched variant as an anti-ship missile system.