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Unmanned aerial vehicles (UAVs) already proliferate in the skies over Iraq, but their functional evolution continues well after their tour of duty in a war zone. The U.S. military reportedly has approximately 750 UAVs operating over Iraq and Afghanistan, including small hand-launched vehicles used by Army soldiers and Marines.

Smaller UAVs (such as the 5-pound Dragon Eye) are equipped with incredibly small thermal imaging cameras, while their bigger, badder brothers, the Predators may possess larger turrets with many more features. Sometimes, size does matter. Either way, these cameras can find an easy transition to civilian applications. In the aftermath of Katrina, a military Drone found its first official use in civilian applications, attempting to locate pockets of survivors from their heat signature.

Regardless of the UAV model, there is one common denominator vital to the successful accomplishment of any mission: the “eyes”, or optical surveillance sensors, typically mounted in a ball-shaped turret or “gimbal” under the nose of most models of UAV. What exactly can these “eyes in the sky” see these days? These sensors usually consist of a combination of electro-optical (EO) cameras used for daylight operations and an infrared sensor (IR) for use at night. The sensor payload may even include laser sensors, such as laser range finders and spotters. No death rays yet….that we know of.

Some of the obstacles being addressed in the area of EO/IR cameras include size and power issues, optical acuity as well as secure wide-band transmission of images and video in “real-time”. Wide-band communication capacity is a major component with all that real-time imagery being beamed around. These images can be transmitted to ground stations using satellite or line-of-sight communications links. Information can even be relayed to another aircraft for further processing or relaying. There have been some good technological advances made, but it may not be as challenging to advance the technology as to get all that technology into a limited space.

It intuitively follows that overall reduction of the size of the camera or optics allows for payloads containing larger numbers and/or varieties of sensors. But, working within the constraint of minimal sensor size can also less than desirable effects, such as a corresponding reduction in spatial resolution, which in some cases may actually reduce the effective operating altitude of the craft. Camera vibration and stabilization issues, accurate GEO-location, and visibility challenges in the environment are just a few of the myriad of issues defining the evolutionary path of the sensor payload.

Manufactured by L-3 WESTCAM, the MX-15D is an example of one of a new breed of new imaging turrets, possessing a laser which utilizes a compact diode-pumped laser combined with an EO/IR range sensor. No, the laser isn’t for shoot-outs, it’s for “spotting” (highlighting an object or person) or determining range. Why is the “diode-pumped laser” such an innovative addition? Generally, diode-pumped lasers have overcome problems associated with other pumping methods which are less energy efficient and generate a lot of heat. Subsequently, this heat has to be properly removed, so the laser has to be cooled to maintain proper working conditions. Without the thermal burden of other methods, diode-pumped lasers can be more compact with reduced power requirements. Lower power requirements, reduced cooling needs and smaller size translates into a smaller payload. Carrying less stuff…is good for mileage.

Better “eyesight” isn’t the only challenge; sensor technology is operationally ineffective if camera instability creates inaccuracies. Flexures, small stretching motions, can occur inside the gimbal itself, contributing to these inaccuracies. There are also some flexures and misalignments between the gimbal and the craft, be it a flying helicopter or a patrolling ground vehicle. These singular inaccuracies are compounded when you combine craft position information with gimbal pointing angles, resulting in target location errors. That would be bad if you lived right next door to an enemy combatant.

These issues are addressed with what is called an Inertial Measurement Unit (IMU). You’ve probably heard the improvement they provide touted by news and weather, though not addressed directly. Simply put, the shaky images of the past are, well, history, thanks to the IMU. An IMU is a closed system utilized to detect motion and position by use of a combination of accelerometers and roll sensors, which track how a craft is moving. The IMU detects the current acceleration and angular rate as well as other craft motions (such as roll, pitch and yaw) and then sums them to find the total change from the initial position. As you may have already guessed, this technology was originally developed for the military in guided missiles; it found its way into space exploration before returning to earth in military and law enforcement applications. And, yeah, also in providing those “unshaky images” your local newscaster brags about.

Another issue involves “night vision” capability. There are a couple of primary ways to accomplish “night vision”. You can use IR and detect a living person by heat emission in the infrared range of the spectrum or you can magnify the available ambient light. Enhancing the resident multi-spectral capabilities translates into the ability to read license plates from long distances in darkness, without auxiliary lighting. This can be accomplished by using what is referred to as charge-coupled device technology (CCD).

CCD technology involves an image being projected by a lens onto a capacitor array, which causes each capacitor to accumulate an electric charge proportional to the light intensity. If the electrodes are placed so that a pixel is surrounded by a negative voltage, then the photoelectrons will accumulate in the middle of the pixel. Technology developed in the 1960’s, CCDs were initially adopted by astronomers for obvious reasons, and commonly respond to 70% of the light striking the surface (as opposed to photographic film, which captures only about 2% of the incident light). But it provides more acute, real-time information even in low-light conditions.

Laser pointers/illuminators are another area where mounted cameras/sensors have made advancements. Typically utilized by law enforcement (but not so much by news- casters and weathermen yet) one diode laser pointer on the market allow an observer equipped with night-vision goggles to see a 30-megawatt laser beam and spot targets while the beam itself remains invisible to its surroundings. Helps if you’re searching for someone in the dark with only the person in the helicopter saying, “you’re getting warmer…now a little to your left”. Now, you just spot ‘em with a laser and ”X “ marks the spot.

If you want to see someone in the IR range, an advanced Indium Antimonide (InSb) infrared imager technology might be for you. It involves applying a magnetic field to a semiconductor, which separates the electrical charges that are created when the surface is illuminated. As positive and negative charges migrate to different parts of the semiconductor, an electromotive force (emf) is created, which is proportional to the intensity of the light. This technology is just another way of accomplishing the same end: night vision. And in the end, it doesn’t matter as much “how” you can see, only “that” you can see. What are they looking at? It’s not always escaped convicts. Sometimes its stranded fishermen, lost hikers and the occasional fraternity hazing ritual.

While advancements in “laser targeting capability” might not be a good fit with civilian missions…even in law enforcement…other sensors innovations might find an easy transition into civilian applications. Other sensor options may include a third-generation thermal imagers, multiple TV cameras, a laser designator, an autotracker, or a high-resolution CCD TV camera. More complex models may incorporate a boresight module can automatically aligns the thermal imager and TV sensors to the “centroid” of the laser spot. What is a centroid and why would you even want to align to it?

The centroid of an area is similar to the center of mass of a body, depending on the geometrical shape of the area. Once locked onto the center of a mass, a camera can track it…or spot it with a laser and shoot at it. Depends on whether you’re flying over Dallas or Baghdad. Co-aligning the thermal sensor and the TV sensor on the centroid assures both sensors are aligned to the same coordinates, assuring that you’re thermally imaging exactly what you are looking at. You do not want to be thermally imaging a “hotspot” in a building while centering your TV sensor on a storage shed just behind it and tying to direct firemen to the source of a fire. Creating algorithms to calculate the center of a moving centroid is not a trivial mathematical problem, but nestling a package of electronics and cameras in such a tight place can be a big challenge.

There are also features such as “image fusing” (allowing for the combination of multiple image modalities into one image with no information loss). Simply put, image fusion is the ability to electronically superimpose two different types of images onto one screen for interpretation, which in turn allows more information to be viewed on a single imaging screen. A real time image from a camera superimposed over an IR image might allow you to locate someone in context with other visual structures.That’s the difference between determining, “the person of interest is 55 meters at 224 degrees from you present location”, and “He’s behind the dumpster.”

It’s a no brainer that the paparazzi is chomping at the bit to get their hands on this type of technology. It’s available….but for what it costs, major magazines can’t upgrade their gimbels AND pay for pictures of Tom Cruise’s new baby, too. But, it’s only a matter of time.

So, if you’re a celebrity, the next time you see that big ball hanging under a plane or helicopter, smile. You’ll want to look your best on the cover of the National Enquirer.