Military Embedded Systems

"For want of a nail, the shoe was lost." Forget about shoes; warfighters need portable power


February 17, 2011

Chris A. Ciufo

General Micro Systems, Inc.

Chris expresses his concerns over the inefficiency of portable power systems in real-time situations and the need for battery overhaul.

I recently attended AFCEA’s 20th annual West 2011 (“West”) convention held in San Diego. The Marine Corps also held their annual Marine West at Camp Pendleton just north of San Diego during the West event. Where West had men in dark suits wearing badges that said “Lockheed Martin” or “Raytheon,” Marine West had Marines and two-star generals confidently strolling in combat boots and BDUs. West was held in the air-conditioned convention center downtown, and Marine West was in a mammoth plastic tent outside in 80-degree weather. The attitudes of the attendees differed, too. Biz Dev execs schmoozed PMs and PEOs in San Diego, while buzz-topped former grunts and COs at Camp Pendleton swapped war stories with barely boot-camp graduates and battle-hardened Marines.

Yet despite the overwhelming differences between these venues, I noted lockstep similarities in the attitudes and the displayed equipment addressing warfighters’ needs. For instance, even though West (co-sponsored by the U.S. Naval Institute and the proximate Naval Base San Diego) had a decidedly naval focus, the emphasis remained on systems that were rapidly deployable, effective, and portable.

Portability brings unique challenges. Assuming cost is no object – but it always is – it’s SWaP that drives the design. At both events, row after row showed COTS platforms that were easily mounted on MRAPs or HMMWVs, man-packed, or tucked inside robot drones. On display at Marine West in the QinetiQ booth was an epaulette-mounted (shoulder) device about the size of a sandwich. Portable enough, for sure. A coiled cord connected to a wrist-worn controller with a small LCD display to complete the Ears/SWATS Shoulder Worn Acoustic Targeting System. Relying on a 10-12 hour battery, the system uses microphones to pinpoint gunshots fired at warfighters.

Funded out of PEO Soldier’s SWATS program and part of the Army’s Individual Gunfire Detection System – and I suspect inspired by several DARPA gunshot location systems dating back to the 1990s – the 1 W, 1-pound system forms a 25 m “bubble” around a soldier to provide relative bearing and absolute position of firing combatants. Compass, GPS, DSP, and sensors all work in lockstep to provide visual or audible cues before the next round finds its mark with deadly results. While highly effective and exceeding the ORD requirement, it seems to me that the 12-hour (max) life of the battery is too short for the typical mission and forces warfighters to carry extra batteries. Portability suffers as the need for batteries grows.

Batteries add weight that could be used for ammo, MREs, or water. QinetiQ is already working on Gen 2, which will be smaller but battery life is similar. If money was no object, an SoC or ASIC a la a cell phone design would save the day. At “nearly $10,000 each,” the Army’s 13,000 order is hardly high volume and certainly not in the realm of custom cell phone ICs. Interestingly, Raytheon BBN Technologies has the Boomerang Warrior-X, a similar portable soldier-worn system with excellent under 7.5 degree bearing error and +20 percent range error, but still a 12-hour battery life. Vehicle-mounted versions of both systems exist to protect convoys, with virtually unlimited on-board power. That makes them sort-of portable.

But once away from a vehicle and dismounted, portable power is nearly as important as a weapon, because the entire mission often resides on transmitting images, video, and sensor or voice data back to base camp. Whether on recon or lasing a target, the portable equipment still needs juice. About 10 battery and power converter companies were present showcasing rugged designs, most of which relied on the COTS Li-Ion or civilian Eveready-style batteries. And even though the U.S. government is pouring money in electric vehicle battery research, batteries have changed little in the past five years and retain existing pros and cons. The exhibitors at House of Batteries, for instance, reminded me that the FAA won’t transport Li-Ion on commercial flights anymore due to the risk of fire. And fuel cell batteries – a cell phone “hopeful” a few years ago – may off-gas flammable material that’s bad news on a battlefield.

But there’s hope for portable power. The batteries are often good enough, while the system power requirements keep dropping. Besides multicore, deep-sleep CPUs from ARM, Intel, and others, and mundane things like high-efficiency DC-DC converters, there’s also LED lighting contributing to saving portable energy. On the latter, the more output lumens per consumed watt, the more energy available for the rest of the system. LED-backlit LCDs, panel lights, and local spot lamps save energy and extend battery life. And during the day, desert geographies like the Middle East can use portable solar panels like those from Iris Technology Corporation’s SPACES system.

The plug-and-go simplicity of this system, along with solar cell portability, caught my attention. The nearly $11 million in USMC contracts for the Solar Portable Alternative Communications Energy System bought 1,650 modules that accept, among other sources, vehicle power, BA-XX90 and zinc-air batteries, and rollable solar panels. Two 12-3 VDC outputs are available to charge BA-XX90 batteries1, power radios, and even USB dongles for GPS, cell phone, and laptop.

Every little bit helps. From solar cells to lower-power electronics, saving power and extending battery life in portable systems are crucial to the success of many missions. Judging by the number of COTS vendors focusing on portable power, no shoes will be lost for lack of a nail. Or battery.

Chris A. Ciufo, Editor [email protected]

1 Clearly you wouldn’t use a battery to charge the equivalent battery – you’d just swap it out. Instead, SPACES can convert energy from one battery type to another at 96 percent efficiency when field ops demand flexibility with on-hand equipment.