Energy-Efficient Technologies for the Dismounted Soldier (1997) / Chapter Skim
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7 Advanced Concepts
7 Advanced Concepts
Pages 131-148
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From page 131... ...
Systems that incorporate low power electronics technologies, energy conscious design techniques, and suitable network architectures and protocols can cumulatively provide for improvements of several orders of magnitude. This chapter discusses the advanced concepts involved in achieving energy sufficiency for the dismounted soldier of the future.
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From page 132... ...
While the Army has been focusing mostly on improving energy sources, the commercial world has also been exploring new technologies and system configurations to reduce power requirements. Commercial Electronic Systems The performance of electronic systems is expected to continue to improve exponentially for at least the next three decades (see Chapter 41.
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From page 133... ...
Several segments of the commercial electronics market, especially devices for digital signal processing, are working to improve the energy efficiency of key technologies used in portable products similar to products required by the Land Warrior. The historical data on the energy dissipation of these devices in terms of the power required to execute one MIPS (million instructions per second)
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From page 134... ...
Unlike the straightforward requirement for the laser red dot, video transmission has major requirements for bandwidth arid compression son e to process the video data, which will result in additional power requirements for the system. Simulations of the trade-offs between electric power and fimctional capabilities would help the Army quantify the energy costs of the additional electronics arid reduce overall power requirements.
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From page 135... ...
USING COMMERCIAL TECHNOLOGY IN THE LAND WARRIOR SYSTEM In order to quantify the advantages of using energy-optimized designs, the committee developed assumptions and estimated future power requirements based on commercial state-of-the-art technologies. Using the power requirements of the objective Land Warrior system as a starting point, Table 7-2 illustrates the magnitude of the differences between the Army's current power requirements and power requirements that could be achieved using equipment comparable to the commercial equipment expected to be available in 2001.
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From page 136... ...
Laser Detectors 0.600 0.050 0.025 Helmet-Mounted Display 4.900 0.220 0.025 Imager < 0.100 0.050 0.025 Subtotal 5.600 0.320 0.075 Weapon Subsystem Laser Rangefinder 0.050 0.050 0.025 Laser Aiming Light 0.075 0.005 0.005 Digital Compass 0.350 0.005 0.002 Thermal Weapon Sight 5.525 1.100 0.160 Subtotal 6.000 1.160 0.192 Wireless Sensor and Display 0.100 0.050 Interconnect TOTAL SYSTEM POWER 56.70 3.78 1.91 aPower requirements reduced by design improvements. bPower requirements to accommodate range and bandwidth for the squad radio are unbounded; reductions will require improved architecture.
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From page 137... ...
Although predictions of future soldier functions were not included as part of this study, the committee expects that the Army wait have to take into account the likely increase in power requirements in its own analyses of future dismounted soldier systems. Table 7-3 lists the specific assumptions used by the committee in making the projections of technical progress for each of the Land Warrior functions delineated in Table 7-2.
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From page 138... ...
2015 (0.007 W) Display technologies allowing refresh rates of 1 frame/see will reduce power by a factor of 30.
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From page 139... ...
Laser Rangefinder 2001 (0.05 W) 50 mW from analog electronics, with negligible power from the 0.75 W laser because of the low duty cycle.
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From page 140... ...
The control electronics will be able to exploit the reductions in power requirements made possible by commercial advances in electronics technology. The sensors themselves may not realize the same advances, but, as the committee noted in Chapter 5, most of the high energy consumption by these devices in the ~.
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From page 141... ...
Clearly, the Army would benefit from a concerted effort to improve the energy efficiency of individual displays and sensors so that additional functions could be added without increasing total energy consumption. Radio Communications Table 7-2 clearly shows that as power requirements for the subsystems are reduced the percentage of energy required for radio transmissions increases.
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From page 142... ...
Energy Requirements for Analog Processing and Analog Devices The energy source requirements for the sensors, displays, radio receiver, analog portions of GPS, video cameras, laser devices, and imagers can be estimated using the following equation: Ma = Pa DC Tm / Es Ma = the weight in kilograms of batteries that support the analog processing. Pa = the power of the device in Watts (from Table 7-21.
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From page 143... ...
indicates that the soldier would have to carry only 1.2 grams of lithium ion battery to supply the energy for this task. Energy Requirements for Data Transmission The energy consumption of a transmitter has three primary components: analog processing (amplifiers, mixers, and oscillators)
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From page 144... ...
As explained in Chapter 6, by making optimistic assumptions about the radio transmitter efficiencies and radio channel characteristics, a reasonable lower limit for the energy to transmit one bit of information can be found. As shown in Tables 6-2 and 6-3, the required energy varies with the range of the radio link, the radio transmission frequency, and the antenna type and location, all of which are determined by the network and system architecture.
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From page 145... ...
that uses shorter distance transmissions is required. To see the difference, one only has to calculate the requirements for a transmission of O.S km at I.5 GHz over open terrain, an EC = 0.0000017 Wh/Mb that would probably be dominated by the analog processing in the transmitter instead of the output power.
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From page 146... ...
PARADIGM SHIFTS From the considerations described above, it is clear that the Army will not be able to achieve its vision of providing the soldier with situational awareness entirely and that energy sources alone will not account for all of the limitations on dismounted soldier capabilities. Energy sufficiency through the use of energyefficient technologies, on the other hand, is achievable from a purely technological standpoint by 2015 and could become reality for the Army After Next.
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From page 147... ...
Consistent with using learning curves to move toward lower energy consumption, designs should move towards lower operating voltages. This is especially important for digital functions (Chapter 5)
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From page 148... ...
In many large companies, military and commercial products are developed, produced, and marketed by different business units with very different goals and objectives. Evidence of this is that a major switch in emphasis to low power electronics as a solution to the battery life problem in consumer electronics began in earnest in the early 1990s (see Chapter 51.
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