It would be nice if you could scan the terrain around you to be able to make up a small map if you wanted. You can already scan for ores using the ore scanner so if you had something that told you the distance away (with a max range) a piece of terrain is it would be a very nice feature.
For vehicles I think it would be a nice detection system. Same premise as the terrain where it would simply send out a ray directly in front and tell you how far the vehicle is. The radar would include two modes for vehicles or terrain.
Additionally, the radar could penetrate the ground and tell multiple contact points so that you could get an accurate representation of the ground within your max range.