The U.S. Army and Air Force has invested billions of dollars in weapons training ranges that are instrumented (covered with sensors, including vidcams). The air force took the lead in this, and has dozens of such ranges, some of them created on the spot with portable equipment that can be flown to air bases, to create an instrumented range as needed for training.
One of the more comprehensive ranges is at Eglin Air Force Base, which is on the Gulf of Mexico, and includes over 200,000 square kilometers of open water for training against naval targets. Because of all the electronics involved, the air force contracts out maintenance and upgrades for ranges like this. The Eglin facility costs Over $67 million a year to maintain, and even more to operate. These ranges undergo upgrades regularly, because of new technology. This can cost over $100 million per upgrade.
The Eglin facility is used for testing and training using smart bombs and missiles. The extensive sensors enables pilots and analysts to tell exactly what happened when a smart bomb or missile was fired and hit, or missed, the target. This is great for training, and even more useful for those developing and maintaining the weapons.