The Army envisions a future uniform-and-electronics ensemble for the LW of the future. The committee believes that soldier electronics requiring a mere 2 W average power, 5 W peak power is attainable in the far term if the recommendations of this study are fully implemented. Using a 200 Wh/kg battery, available within the next few years, such a system could operate continuously for about 100 hr in a 1 kg package. However, concepts for powering the reduced needs of future soldiers should take advantage of likely reductions in the scale and distribution of power demand and consider options such as energy-harvesting technologies to provide reliable power at such low levels.
Recommendation 11: The Army should aim for a future soldier system capable of no more than 2-W average power, 5-W peak power. Achieving this will free the soldier from worries about power shortages on the battlefield and greatly enhance combat effectiveness.
Modeling has the potential to be a tool that saves time and money in developing efficient portable electronic systems if accurate system input can be supplied. Modeling can complement experimental data as it narrows down the parameters of optimization. The data ultimately need to be verified with experimental data, but the modeling can expedite the selection of a power source. Ideally, the military should develop and acquire new equipment based on recommendations and considerations from power sources modeling in order to maximize the lifetime of the equipment.
Substantial power reduction can be achieved through management techniques that power down unused components. Additionally, the power dissipation of components in standby mode should be reduced as much as possible; this will become increasingly important as silicon technology continues to lead to increased leakage currents. Actual measurements of the varying loads (rather than crude duty-cycle guesses) will allow simulating the dynamic operation of LW electronics in concert with a power source simulator.
At the highest level of simulation, given a range of mission scenarios, a suite of soldier equipment, and the size and makeup of combat teams, the Army should be able to determine optimum types, quantities, and distribution of power sources (and their fuel and recharging requirements). At the lowest level, the Army should be able to perform comprehensive analysis of every element and subelement in the entire system. Such an analysis must extend all the way from the leakage, clocking structure, and power-down capabilities on individual chips to the duty cycle on the laser designator, display, or radio, and everything in between. Engineers and scientists who are well versed in all of the modern technologies for very low power SoC design need to be sought out and used in this important effort to characterize the soldier requirement.
Full simulations of OFW power sources and sinks would also help to determine the directions that developments must take to have the most impact on power. While models based on experimental data can be used to expedite the proper selection and matching of power sources, higher order models could be used in simulations to tailor soldier applications to the most likely soldier modes of interaction, thus reducing power requirements for computation and communication. The Army has ready access to high-performance computing resources that are capable of supporting such important tasks, and such simulations can go a long way toward improving energy efficiency in military electronics.
Recommendation 12: The Army should develop a modeling capability for soldier equipment that includes power sources and also enables detailed simulation, verification, and analysis of power requirements for given operational parameters.
Ensuring adequate power for soldier systems is by no means a simple problem; if it were, the Army would not have asked the National Academies to do this study. It is a multidimensional challenge, and the solutions are found by considering not only energy sources but also energy sinks and energy management. The good news is that solutions exist in all regimes to satisfy known power requirements, and major breakthroughs in power/energy source technologies are not needed. To satisfy the needs of future warriors on the battlefield, the Army must move power to the forefront of considerations in developing and acquiring soldier electronics, especially communications. It also must invest in the means to analyze power requirements so as to take advantage of reductions that can only be achieved by efficient power management.