A challenging thermally efficient and environmentally sealed enclosure was needed to protect a hardware/software system used to process multiple forms of data from surveillance systems.
Military surveillance systems are designed to make records of events of interest. But finding a particular event among one month's worth of surveillance recordings can be challenging and time-consuming. For that reason, EchoStorm Worldwide (www.echostorm.net), a leading supplier of innovative video and sensor management solutions for military, government, and commercial applications, developed its adLib software. The digital content management solution captures, standardizes, processes, and fuses video, image, and data inputs from multiple sources. It also disseminates the combined information to users in a secure standard format in near real-time regardless of location, bandwidth, or playback device.
The adLib software (Fig. 1) also makes it simple to pick out specific information from the archived security material. Such a powerful software package has useful applications in a wide variety of end-user markets, but is particularly useful in surveillance, data-recovery, and data-processing applications. As Kevin Dumville, EchoStorm's director of marketing and public relations, explains: "Our primary customers use the product for what we call situational awareness,' to understand what someone or something is doing at a particular time and place. In a disaster, a first responder might use it as part of a rapidly deployed mobile command center with a large-scale, near real-time view of storm devastation in order to optimize recovery response. Or, it might be used in a unmanned aerial vehicle (UAV) flying over the same area in a daily loop to see what was going on in a designated area at the same time each day."
It was the latter application that officials from a United States government agency had in mind when they approached EchoStorm earlier this year. The goal was to gather aerial surveillance video of specific areas, then either watch the video in real-time or easily retrieve the archived data for later viewing. Thus, if the agency wanted to know what happened at a particular location on Dec. 3 at 10:00 a.m.., they need only enter that search criteria to immediately retrieve the video footage. Given that the likely equipment currently in use was a common VHS-type device with a printer, the adoption of adLib software would be a far more functionaland expedientalternative.
After some discussion between vendor and client, EchoStorm developed a product called Mobile Data Archive and Retrieval (MDAR), which combines both software and hardware into a single solution. The adLib software would process incoming video from UAVs and store it on a hard disk drive. The software and hardware components would be integrated into a rugged enclosure and mounted into a Humvee for mobile use.
Ironically, the enclosure posed the greatest challenge for EchoStorm. The software and hard drive would not work in an off-the-shelf solution for several reasons. As Clark Kreston, EchoStorm's program manager for the MDAR Project, explained: "The customer had two very specific requirements. First, they wanted the software to be mounted in a particular space in an existing shelter within the vehicle. In order to fit in this shelter, it had to meet some strict environmental criteria, such as resistance to temperature, vibration, and humiditythe kind of conditions that would be experienced as the vehicle moved around the countryside." In addition, he noted: "The second requirement concerned storage capacity. The customer wanted 30 days worth of storage; that translated to six terabytes of hard drive storage, or six separate hard drives. Not only would the enclosure have to fit the software and all the hard drives, the hard drives had to be easily removable. That's not the kind of thing you can just buy in a store."
Kreston also mentions that the physical shape of the box became an issue: "The initial specs from the prime contractor called for a unit that was roughly 9-in. high, 9-in. wide and 27-in. deep. When we actually went out to install the MDAR box in the intended location, we discovered that there was an air-conditioning duct in the shelter that had not been accounted for. So, instead of having a full-sized unit that met the original specifications, we had to cut a step out of the back of the box for it to fit around the duct."
EchoStorm had some enclosures fabricated locally, but they didn't meet the requirements. While the software worked properly, the hardware didn't, largely due to overheating. EchoStorm knew that outside assistance was needed to solve the problem, seeking help from Carlo Gavazzi Computing Solutions. As Jim Tierney, vice-president of Government Systems for Carlo Gavazzi, recalled: "When EchoStorm initially began talking with us, they were only looking for a hard drive bay for their own solution. After we understood the application better, we realized that their box was not deployable. They were taking a commercial-grade box and trying to deploy it in a rugged, caustic environment. So, instead of getting us to just do the drive bay, we suggested looking at how we could solve the entire packaging issue."
After seeing enclosure solutions that Carlo Gavazzi had created for other customers, EchoStorm felt confident the company could solve its enclosure dilemma. As Kreston notes, the wide range of capabilities offered by Carlo Gavazzi simplified the decision: "Obviously, we felt they had the necessary mechanical expertise. But they also assigned an electrical engineer, a manufacturing engineer, a software expert, and a cabling person to the project. And having it all provided by one vendor made the process extremely convenient."
In studying EchoStorm's design efforts, Tierney noticed some possible improvements: "Structurally, their solution may have been viable. But we saw that they were bringing in air from the outside environment to cool off the hard drives inside. The sand and dust that's usually found in the foreign countries where the vehicles are deployed is almost like talcum powder. Filters clog quickly in this type of environment, and they would have had to be changed quite frequently to have any chance of working."
To overcome this design flaw, one of the main directives for Carlo Gavazzi would be to design a completely sealed box that would let air circulate freely through the MDAR box without bringing in the outside contaminants (Fig. 2). As Tierney explains, "We created a sealed box, called a re-circulating air chassis, which protects the internal electronics from the harsh environmental conditions. There's still a fan inside, but because of its tightly welded design, no sand or dust, not even salt air, will enter the enclosure. Consequently, the device will never require filter changes." Kreston adds that the enclosure's thermal efficiency helped solve the overheating problem: "The sealed unit uses the sides of the box to radiate heat. The operating environment for this device is very hot, and our own solution was not doing a great job of dissipating the heat."
Kreston further describes the solution: "Carlo Gavazzi constructed its box out of a thick, machined aluminum, about one-half inch thick or greater in most areas. Our existing box was also aluminum, but it was sheet metal aluminum, much thinner than Carlo Gavazzi's. The thicker aluminum machined surfaces, especially the walls, are very effective for thermal transfer. So the heat that's developing inside the box is quickly dissipated, keeping the device cooler."
With the help of Carlo Gavazzi, the MDAR box was designed to mount easily on slides. The mounting process is a quick installation, one that the government customer can actually undertake themselves. The solution was effective for EchoStorm, and developed quickly according to Kreston: "From the first time we sat down with the Carlo Gavazzi engineers, talked things through, and did some preliminary design drawings until we had a suitable prototype, it was about 60 days. The design of the actual prototype alone took only about a week. We knew they could work fast, and that was one of the factors we considered before choosing them."