Launch Reading the ground Identifying the target Hitting the target Future technology BGM-109 Tomahawk

The missile compares the ground with information stored in its memory

Digital Scene Matching Area Correlation (DSMAC) compares what it can see on the ground with a digital rendition of its target.

This technology is complicated and expensive but has been shown to work.

But it is only as good as the intelligence that underpins it. It will never stop a missile hitting a long-abandoned target building or a civilian shelter if the targeting information is not up to date.