The U.S. Department of Defense recently ordered another 22 Kestrel wide-area persistent surveillance systems to detect hostile activity over, well, a wide area. These systems are mostly used in Afghanistan.
Kestrel is a collection of sensors (six day and heat sensing vidcams) mounted in a gimbaled mount (so that they can rotate and see in all directions) and is attached to an aerostat. These are 32-85 meter (100-250 foot) long, helium filled, unmanned blimps. The larger of these blimps are more than twice the size of the more familiar advertising blimps. An aerostat is designed to always turn into the wind and stay in the same place. An aerostat is unpowered and secured by a cable that can keep the aerostat in position at its maximum altitude of 5,000 meters (15,100 feet). The cable also supplies power, which means the aerostat can stay up for about 30 days at a time before it has to be brought down for maintenance on its radars and other sensors.
The Kestrel camera system and the software that controls it was originally developed for use on small aircraft and UAVs. That version was called Constant Hawk and it arrived in Iraq six years ago. The software part of Constant Hawk turned out to be crucial for the success of the system. It used image analysis that was basically just another pattern analysis system. However, it's was a very successful system. The U.S. Army named Constant Hawk one of the top ten inventions for 2006. The army does this to give some of the more obscure, yet very valuable, developments some well-deserved recognition.
Pattern analysis is one of the fundamental tools Operations Research (OR) practitioners have been using since World War II (when the newly developed field of OR got its first big workout). Pattern analysis is widely used on Wall Street, by engineers, law enforcement, marketing specialists, and now, the military. Constant Hawk/Kestrel uses a special video camera system to observe a locality and find useful patterns of behavior. Some of the Constant Hawk systems were mounted on light aircraft, others are mounted on ground structures, especially towers. These evolved into Kestrel and used on aerostats.
The software compares photos from different times. When changes are noted they are checked more closely, which has resulted in the early detection of thousands of roadside bombs and terrorist ambushes. This has largely eliminated roadside bomb attacks on supply convoys, which travel the same routes all the time. But those routes are also watched by the cameras. No matter what the enemy does the system will notice.
Constant Hawk/Lestrel, like most geek stuff, does not get a lot of media attention. Mainly it's the math, and TV audiences that get uneasy watching a geek trying to explain this stuff in something resembling English. But it works and the troops want more of it. The troops like tools of this sort mainly because the systems retain photos of areas they have patrolled and allows them to retrieve photos of a particular place on a particular day. Often, the troops returning from, or going out on a patrol, can use the pattern analysis skills we all have to spot something suspicious or potentially so.