无人机系统路线图 Unmanned Aircraft Systems Roadmap(57)

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The value of survivability in the UA design equation will vary with the mission, but the DarkStar lesson will need to be reexamined for relevance to future designs.  To the extent UA inherently possess low or reduced observable attributes, such as having seamless composite skins, fewer windows and hatches, and/or smaller sizes, they will be optimized for some level of survivability.  Trading performance and/or cost for survivability beyond that level, however, runs counter to the prevailing perception that UA must be cheaper, more attritable versions of manned aircraft to justify their acquisition.  As an illustration, both the Air Force and Navy UCAVs (now part of the J-UCAS program) were originally targeted at one third
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the acquisition cost of their closest manned counterpart with the same tactical range, the Joint Strike
Fighter (JSF); although the range and payload requirements more than doubled in addition to the
signature goals being lowered, they are still expected to cost less than that of their manned counterparts.

Aircraft acoustic signature is often overlooked as a key low/reduced observable requirement for UA use
in the force protection, homeland defense, and special operations roles.  These roles can be better
supported by using quieter vehicles that are less susceptible to detection.  Electric power systems, such as
fuel cells, offer lower noise signatures for smaller UA while providing comparable mass specific power
(equals endurance) to that of internal combustion engines (ICE).  

Survivability enhancements also need to be considered in a systems context.  While keeping the UA from
being shot down in a hostile environment is the most obvious challenge, an adversary can employ other
techniques to make an UA ineffective such as communications and navigation jamming.   
Appendix K further discusses UA survivability.

4.3.6 System Cost Control
Empty weight cost is a commonly used metric in the aviation industry because it tends to remain constant across a variety of aircraft types. That number today is roughly $1500 per pound.  Table 4.3-2 provides the empty weight and cost data for DoD UA depicted in Figure 4.3-3.  It shows current DoD UA platforms cost approximately $1500 per pound of empty weight and $8,000 per pound of payload capacity as one “cost per capability” metric.  Figure 4.3-4 takes this metric further by factoring in UA endurance to also provide a link between performance and cost in terms of dollars per pound-hour. 
4.4 PAYLOAD TECHNOLOGIES
Payloads currently in use or envisioned for use on UA fall into the four general categories of sensors (electro-optical, radar, signals, meteorological, chem-bio), relay (communications, navigation signals), weapons, and cargo (leaflets, supplies), or combinations of these.  The desire for endurance in many UA demands a high fuel fraction, resulting in a corresponding low payload fraction, typically 10 to 20 percent of gross weight. Figure 4.4-1 illustrates this trade-off between endurance and payload weight. Appendix B presents a detailed evaluation of future sensor technologies for UA.
　
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