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Wide-Area Motion Imagery Systems: Evolution, Capabilities and Mission Sets

John Marion
RUSI Defence Systems, 5 January 2017
Aerospace, Air Power and Technology, Technology
Even among security experts and military professionals in Europe, wide-area motion imagery (WAMI) is seldom discussed and is often confused with full-motion video cameras or other systems. This is despite its important capabilities for many security users.

More than just another look-and-see sensor, WAMI (also referred to as wide-area persistent surveillance) is a powerful data-gathering tool that has been operational in the field for more than a decade. Indeed, since the technology first debuted as a Quick Reaction Capability for the US Army, it has undergone a rapid evolution with important capability implications.

Once bulky beasts, WAMI systems have been getting smaller, yet more capable. This has allowed them to be integrated on new platforms, going from aircraft such as the MC-12W to tethered blimps, helicopters and tactical unmanned aircraft systems (UAS).

With this proliferation of parent-platforms, WAMI has transitioned beyond the battlefield. For example, the sensor can provide security at sensitive sites or be deployed along international borders to detect smuggling and illegal migration flows. It can support relief and rescue missions too, providing real-time environmental and structural damage assessments.

Origins and Development

The first WAMI system was developed by Lawrence Livermore National Laboratory’s Sonoma Persistent Surveillance Program. The original concept was to put WAMI on satellites in order to track movements at suspected WMD development sites from space. But the National Reconnaissance Office did not buy into the idea.

The US Army, however, was interested in the sensor—but for another mission set. Coalition forces in Iraq and Afghanistan were facing a serious and growing threat from improvised explosive devices, and the service was looking for an intelligence, surveillance and reconnaissance (ISR) tool to combat the insurgents setting the roadside bombs.

The US Army deployed its first WAMI system – Constant Hawk – to Iraq in 2006 and then to Afghanistan three years later. That first system had serious limitations compared with modern derivatives; it weighed nearly 1500 lbs (and was mounted on manned Shorts 360 and King Air 350 aircraft), lacked infrared cameras, and required highly trained analysts to read its imagery.

However, the technology proved effective in the field. And even as Constant Hawk was being deployed, development on WAMI continued apace. In 2007, the US Air Force and Marine Corps deployed their own Angel Fire system, and two years later, Constant Hawk was enhanced with infra-red, giving it a day/night capability.

Following this upgrade, and at the request of the US Army and ISR Task Force, Constant Hawk was reduced in size and weight and adapted for use on an aerostat, or a tethered blimp, enabling wide-area surveillance for weeks at a stretch. The new aerostat-mounted system was called Kestrel and used to protect forward operating bases in Afghanistan. Since its initial deployment in 2011, it has racked up more than 200,000 operational hours.

Today, WAMI is still undergoing reductions in size, weight and power requirements, to the point where these systems can be mounted on planes, helicopters, Group 3 UAS and smaller aerostats. This opens the technology to a whole new set of operators and missions—including border security, disaster relief, firefighting, law enforcement, and site protection. WAMI was even used at the Summer Olympics in Rio de Janeiro in 2016.

Principles of Operation

As its name suggests, WAMI entails motion imagery, but there is a huge difference between these newer ISR systems and traditional video cameras. Standard Full-Motion Video (FMV) cameras have very narrow fields of view, which prevents them from effectively covering a large area. An FMV operator must, therefore, know ahead of time where to point this ‘soda-straw’ view.

By contrast, a single WAMI sensor can monitor an entire city-sized area (often more than 100 sq km) at once in real time. A single system operator, bolstered by the WAMI’s automated software, can detect and track hundreds of people and vehicles regardless of separation distances and relative directions of travel.

A single WAMI unit can also support multiple users on the ground, allowing each one to download a different video feed from within the sensor’s vast field of view. In addition, the sensor allows operators to create tripwire-like ‘watchboxes’, which send them an automated alert should a mover cross into a designated area. All this maximizes situational awareness while reducing manpower requirements and equipment costs.

When WAMI is paired up with FMV (in Afghanistan, the Kestrel system is mounted on its aerostat along with an FMV camera), the two sensors support one another. The WAMI system, which images in medium resolution, will detect and track movers over a city-sized area, and then cue in the high-resolution FMV camera to provide target-identification.

Finally, in addition to its real-time monitoring, a WAMI system acts like a time machine. Most system configurations record, tag and archive all imagery collected during their time in the air (hours, days or weeks). Users can then ‘rewind the clock’ and conduct forensic analyses of significant events over an extended period, all while monitoring ongoing activities in real time. This technique can uncover significant relationships between people, vehicles and locations that might otherwise have gone unnoticed.

Of course, WAMI is not the only airborne wide-area sensor employed by Western forces. There are also recce pods, synthetic aperture radar and ground/dismount movement target indicators. However, while each of these systems excels in its own way, they generally lack the coverage area, field of view, frame rate, resolution, persistence or forensic capability of WAMI.

Recce pods can take a short series of photographs of a large strip of land at ranges of 20–50 miles. But the pod will not generate real motion imagery due to the system’s long focal length and its limited pixel collection rate and processing capabilities. Also, it will not allow for real-time tracking or a rewind capability, and it cannot operate from a long-endurance aerostat.

Another airborne wide-area sensor is synthetic aperture radar (SAR). Often paired up with reconnaissance aircraft such as the U-2 and the unmanned RQ-4 Global Hawk, SAR can generate high-resolution imagery of target areas at ranges of up to 100 miles. It can also function under a variety of conditions that might stymie cameras, such as clouds, smoke, fog and light rain.

However, SAR functions by looking out the side of an aircraft, generating a new frame each time the aircraft moves forward. As a result, the sensor takes mostly still imagery, or at best, a few shots in sequence, but certainly not motion imagery. Like recce pods, SAR also lacks a rewind capability to track movers back in time.

Finally, there are ground/dismount movement target indicators, or G/DMTI. Like WAMI, these radars can be paired with FMV cameras on aerostats, with the G/DMTI conducting the long-range sweep and the FMV following up with hi-res identification. In fact, G/DMTI have a longer detection range than WAMI and can operate in less than ideal environmental conditions.

However, G/DMTI radars, besides having a high rate of false positives and a vulnerability to jamming, do not really image. They can generate moving dots on a screen and connect them into tracks. It remains difficult to tell what each dot is. There is also no way to uncover a connection between a dot at one specific time and date to another at a different time and date.

G/DMTI can be used in conjunction with FMV for border security missions. However, the radar is best used for a deep stare into a barren area with little traffic, with WAMI reserved for border cities and crossings with lots of movers.

Although WAMI has been on the battlefield for 10 years now, its value remains poorly understood by the broader international community. The coverage area of a WAMI system vastly exceeds that of full-motion video, another technology often associated with the term ‘persistent surveillance’, and it allows for a powerful real-time forensic capability that other wide-area sensors lack. This does not mean that it can replace existing systems, but it can enhance and complement them.

John Marion
President of Logos Technologies

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