December 3, 2011: For the last decade, the U.S. Army has used several generations of portable "see-through-the-wall" sensors. The Eagle series of sensors use low power ultra-wideband radio waves to detect what is behind walls (except metal ones). These devices (there are several versions) weigh less than 2.5 kg (5.5 pounds) and all are hand (or arm) held. The M model can detect motion, of people or animals who are up to six meters behind a 20cm (8 inch) concrete wall. The P model can see into the ground (3-4 meters down) and detect objects, as well as tunnels. The V model produces sharper images, but at shorter ranges. The Eagle 45W is mounted on the arm and is very useful in urban fighting, when the enemy is moving through a building you are outside of.

All these devices use rechargeable batteries that are good for about four hours. The older sensors look like a game controller, and put the image on a small screen, as well as being able to wirelessly transmit the image to a laptop computer, which can use software to enhance the image. These non-radar sensors are popular with police and fire departments, as well as anyone who has to search behind walls, or under roads, for stuff that is broken.

This kind of equipment is nothing new. Five years ago, the troops began using the nine pound Radarvision device. While this tool couldn't see through metal walls, it did give you an image of anyone behind any other wall material, including up to a 30 cm (one foot) of brick, concrete or stone. It could also see through multiple walls. Using a 90 minute battery pack, the image was particularly good if someone in there is moving. Competing devices weighed as little as 3 kg (6.5 pounds), and had a range of up to 20 meters (63 feet) and batteries that lasted 2.5 hours. The latest devices use new technology, are lighter and more reliable and produce sharper images. These can also be worn on the arm, with helmet mounted eye piece providing the visuals.

This equipment does not go out on every mission, but it does often enough to force the enemy to be very creative in trying to hide things (usually without success). The troops like this gear because it is portable and easy to use. The sensors can reveal hidden weapons as well as hidden people in a building or case. These sensors also help avoid civilian casualties, because you can check out who is in a building before going in. Kids are relatively easy to identify, which usually means civilians.