Doesn't really work if you're trying to navigate over an ocean. Cruise missile also operate over relatively short distances (1,000km - 5,000km, most being 1,000km - 3,000km) compared to long haul flights, plus they also fly at very low altitudes (which helps them avoid enemy radar) which makes terrain contour mapping easier.
Not to mention, if you're designing a cruise missile, you're not that bother about how your navigation system might interfere with other aircraft, or ground systems in the area. I doubt having thousands of planes flying around shooting radar straight down at the ground would work particularly well.
Not to mention, if you're designing a cruise missile, you're not that bother about how your navigation system might interfere with other aircraft, or ground systems in the area. I doubt having thousands of planes flying around shooting radar straight down at the ground would work particularly well.