The U.S. is installing a tower based radar and vidcam surveillance system along the Mexican border, based on similar equipment used in Iraq and Afghanistan. To keep costs down, and speed up the flow of information, microwave communications are being used, rather than satellite based methods. In addition, ground sensors will also be hidden at some locations. The main problem with this system, is withstanding the efforts of drug (and people) smugglers to disable it. The sensors do work, the troops in Iraq and Afghanistan have proved that, and they had ample opportunity to test it on determined Islamic terrorists trying to get past the sensor systems. But in Iraq and Afghanistan, the towers were usually inside bases, not out on some rural hilltop.
The Department of Defense mainly used Eagle Eye surveillance tower systems. These cost $556,000 each. This security system consists of day/night cameras (with zoom), laser range finder and designator, all mounted on a truck mounted tower The tallest Eagle Eye tower is 107 feet tall, allowing the cameras to spot vehicles and people up to 25 kilometers away. Great for keeping an eye on thinly populated areas in a desert, which western Iraq has plenty of. The earlier 30 foot tower can see out to eleven kilometers, the 60 foot tower out to 16 kilometers and 84 foot tower out to 20 kilometers. The 30 foot tower was adequate for most situations, which usually involved guarding a base, but the taller tower also serves as a communications relay for widely dispersed troops. The towers can be easily taken apart or erected by troops. When temporary bases are set up, an Eagle Eye tower provides the equivalent of a permanent UAV presence, which, just by being there, tends to discourage attacks, or any misbehavior in the vicinity of the base.
The U.S. border towers will be permanent, although it has been proposed that some Eagle Eye systems be bought as a backup, and reserve (when you want to establish a deeper observed zone.) Another problem that may be solved with the border surveillance system, is operator fatigue. Someone, or something, has to watch all these live radar and video feeds.
Research has shown that people staring at live video feeds start losing their ability to concentrate on the images after about twenty minutes. This problem has been known for some time, and the military (not to mention civilian security firms) have been seeking a technological solution. It's actually not as bad with UAVs, because the picture constantly changes, but cameras that are fixed can wear operators out real quick.
The basic tech solution is pattern analysis. Since the most common video is digital, it's possible to translate the video into numbers, and then analyze those numbers. Government security organizations have been doing this for some time, but after the fact. It's one thing to have a bunch of computers analyze satellite photos for a week, to see if there was anything useful there. It's quite another matter to do it in real time. But computers have gotten faster, cheaper and smaller in the last few years, and programmers have kept coming up with more efficient routines for analyzing the digital images. Commercial firms already have software on the market that will analyze, in real time, video, and alert a human operator if someone, or something (you are looking for) appears to be there.
The real time analysis software is rapidly evolving. You don't hear much about it, because if the enemy knows the details of how it works, they can develop moves that will deceive it (or, to be more accurate, make the pattern analysis less accurate.) Already, this software is being used as an adjunct to human observers, and gradually taking over. There will always be a human in the loop, to confirm what the software believes it has found.
The proliferation of video cameras on the battlefield (in UAVs, ground robots and for base security) has provided a huge library of images that show bad guys doing what bad guys do. This can range from moving around carrying weapons, to using those weapons, to the particular driving patterns of people up to no good. This is a unique resource, and the U.S. Department of Defense has put together a library of these images. This is similar to older still pictures libraries, which were eventually used by pattern recognition software to let machines examine the millions of images digital photo satellites began producing decades ago. The basic problem was that there were soon too many pictures for human analysts to examine. Computers had to do much of the work, or else most of the images would go unexamined. This technology was quickly adapted to the kind of combat encountered in Iraq and Afghanistan, and terrorist operations in general. The U.S. border security system will have to add its own library of images, which are unique to people trying to sneak themselves, or drugs, across the border.
Thus, while many of these "electronic barriers" have failed in the past, this time around there's over a decade of success in places like Iraq, Afghanistan, and Israel. The first of these border surveillance systems will be built in Arizona over the next three years. While pundits will question the capabilities of this "new technology," it's not new at all, but the latest version of stuff that has been at work for several decades now.