Energy-Efficient Technologies for the Dismounted Soldier (1997)
Chapter: Appendix B
Appendix B Sample Estimate of Operational Requirements for Land Warrior
Operational requirements for Land Warrior were developed by the Infantry Center in terms of wartime and peacetime operational mode summaries for each Land Warrior subsystem (TRADOC, 1994). As shown in Table B-1, the baseline list of electronics includes a computer, soldier and squad radios, a Global Positioning System terminal, a video capture device, hand-held and helmet-mounted displays, a laser detector, an image intensifier, a laser rangefinder and aiming light, a digital compass, a thermal weapons sight and close combat optic, and a video camera. These are grouped into a computer/radio subsystem, an integrated helmet assembly subsystem, and a weapon subsystem.
Table B-1 also lists the power requirements of the objective Land Warrior system. To estimate these power requirements, the Army defined characteristic mission profiles for each subsystem and then compiled summaries for various operational modes. The wartime operational mode summary tabulated mission profile data defined for various wartime missions for dismounted soldiers, including military operations in urban terrain (MOUT) attack, night attack, MOUT defense, open terrain defense, rear area operations, and civil affairs support. Peacetime summaries were also compiled, based on mission profiles defined for such things as the Army Training and Evaluation Program and Command Post exercises, squad and platoon field training exercises, night training, and live-fire exercises.
An example is the mission profile for the laser rangefinder in an attack in urban terrain (Table B-2). The profile lists each task, the number of occurrences, the time required to perform the task, and the total operating time. This mission profile, which requires 19.54 minutes (0.33 hours) operating time, became part of the wartime operational mode summary for the laser rangefinder (Table B-3).
The Army estimated annual wartime usage by using a baseline planning factor of 30 iterations per year of a 12-day combat scenario. During each iteration, units equipped with the Land Warrior ensemble would participate in 138 hours of operations, as shown in the operational mode summary, with the balance of time being used for rest, refitting, and preparation for the next iteration.
TABLE B-1 Power and Energy Requirements for the Land Warrior System
|
|
Cumulative Peak Power (W) |
Function Operating Power (W) |
Standby (Alert) Power (W) |
Operating Duty Cycle (%) |
Average Operating Power (W) |
12-Hour Mission Energy Goals (Wh) |
|
Computer/Radio Subsystem |
||||||
|
Computer |
18.40 |
14.80 |
1.48 |
8.27 |
99.24 |
|
|
Hand-held flat panel display |
7.70 |
6.40 |
0.00 |
5 |
0.32 |
3.84 |
|
Soldier radio |
||||||
|
Receive |
1.70 |
1.40 |
1.00 |
40 |
1.06 |
12.72 |
|
Transmit |
7.20 |
6.00 |
0.00 |
20 |
1.20 |
14.40 |
|
Squad radio |
||||||
|
Receive |
2.40 |
2.00 |
1.00 |
20 |
1.20 |
14.40 |
|
Transmit |
14.40 |
12.00 |
0.00 |
10 |
1.20 |
14.40 |
|
Global Positioning System |
1.80 |
1.50 |
0.60 |
45 |
1.01 |
12.06 |
|
Video capture |
1.20 |
1.00 |
0.00 |
15 |
0.15 |
1.80 |
|
Integrated Helmet Assembly Subsystem (IHAS) |
5.8 (night) |
5.6 (day) |
0.25 |
2.82 |
33.84 |
|
|
Helmet-mounted display |
|
|
|
|
|
|
|
Image intensifier with integrated flat panel display |
|
|
|
|
|
|
|
Laser detectors |
|
|
|
|
|
|
|
Weapon Subsystem |
7.80 |
6.00 |
0.00 |
2.78 |
33.36 |
|
|
Laser rangefinder |
|
|
|
|
|
|
|
Laser aiming light |
|
|
|
|
|
|
|
Digital compass |
|
|
|
|
|
|
|
Thermal weapon sight |
|
|
|
|
|
|
|
TOTALS |
68.4 |
56.7 |
— |
— |
20.0 |
240 |
In Table B-3, At is the time per iteration that the subsystem is active, and Ct is the computer operating time. Because nearly all Land Warrior electronics depend on the computer, an annual Land Warrior system operating time of up to 2,643.6 hours was calculated based on the computer operational mode summary.
TABLE B-2 Attack Mission Profile for the Laser Rangefinder
|
Task/Event |
Number of Occurrences |
Time for Each Task (minutes) |
Total Operating Time (minutes) |
|
Unstow |
4 |
0.03 |
— |
|
Switch on |
4 |
0.05 |
0.20 |
|
Warm up |
4 |
0.05 |
0.20 |
|
Focus |
37 |
0.05 |
1.85 |
|
Adjust diopter |
7 |
0.08 |
0.56 |
|
Observe |
7 |
2.15 |
15.05 |
|
Trigger/fire |
37 |
0.02 |
0.74 |
|
Read |
37 |
0.02 |
0.74 |
|
Switch off |
4 |
0.05 |
0.02 |
|
Optical zero |
1 |
0.03 |
— |
|
Change battery |
0 |
0.75 |
— |
|
Perform preventive maintenance |
1 |
0.50 |
— |
|
Stow |
4 |
0.03 |
— |
|
TOTAL |
|
|
19.54 |
TABLE B-3 Wartime Operational Mode Summary for the Laser Rangefinder
|
Mission |
Number of Lasings |
Operating Time (hours) |
At (hours) |
Ct (hours) |
|
Attack (MOUT) |
37 |
0.33 |
11.06 |
12 |
|
Defense (MOUT) |
27 |
0.30 |
7.29 |
8 |
|
Attack (night) |
42 |
0.40 |
14.79 |
16 |
|
Defense |
33 |
0.07 |
5.62 |
6 |
|
Rear area operations |
97 |
1.44 |
44.10 |
48 |
|
Civil affairs support |
129 |
1.40 |
44.13 |
48 |
|
TOTALS |
365 |
3.94 |
126.99 |
138 |
REFERENCES
TRADOC (U.S. Army Training and Doctrine Command). 1994. Land Warrior Operational Requirements Document, April 13, 1994. Ft. Monroe, Va.: U.S. Army Training and Doctrine Command.
