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dependent upon receiving GPS satellite signals, any denial of GPS service will impact the mission
effectiveness of the UA, perhaps even causing its loss. Although events like the jamming or destruction
of a GPS satellite are beyond the control of the UA operator, that jamming or destruction would
essentially bring most UA operations to a rapid halt.
Finally, the mission management software can be affected through several means either before or after the
aircraft is launched. Viruses, Trojan horses, and other hostile software agents can infect the UAS’
software and keep the system from fulfilling its mission.
Payloads
Payloads vary according to UA type and mission, with the overwhelming majority of UA payloads being
imaging payloads; therefore this discussion will be limited to imaging payload survivability. Payloads
can be either external, as in a ball or pod that hangs from the aircraft, or internal. In smaller, less
expensive UAS, locating the payload internally does not dramatically decrease vulnerability. Payloads
are generally not specifically targeted in the smaller aircraft because it is just as easy to destroy or degrade
the UA itself.
Payloads are susceptible to physical threats; even though the payload is not likely to be targeted
specifically it may suffer collateral damage from an attack on the UA. Passive payloads may be degraded
by electronic attack, but a relatively long dwell time is required to cause permanent damage. However
active sensors, such as radars, are more susceptible to electronic attack. Even a short-term attack can
cause significant long-term damage.
UAS ROADMAP 2005
APPENDIX K – SURVIVABILITY
Page K-4
Dissemination Means
UAS normally disseminate information via data links. Depending upon the system, information may be
processed onboard the aircraft or transmitted to the ground for processing. In either case, the
communications channel is susceptible to detection, radio direction finding, intercept, and electronic
attack efforts. If the UA is transmitting a live video feed, the communication channel is likely to be
wideband and continually emitting. Encryption of the data links would reduce the possibility of
successful intercept and exploitation. Depending upon the UA system, the dissemination data links and
the command and control links may share the same frequencies and be interwoven through multiplexing
schemes.
The data links and the transmit and receive equipment associated with the dissemination of information
are susceptible and vulnerable to the same efforts that threaten the command and control links. The
dissemination data links on larger aircraft should be encrypted, as they are more likely to be relaying data
that are of interest to higher echelons. Conversely, handheld/small and tactical UA may not require
encryption devices because it is harder to intercept their dissemination signals (closer to the ground
station and flying at lower altitudes) and because the information they collect and disseminate is highly
perishable.
SURVIVABILITY CLASSIFICATIONS
When considering airframe survivability, it is useful to divide UA into three categories (small, medium,
and large) based on size, speed, and operational altitude. These categories are useful for considering the
likely threat environment and application of susceptibility and vulnerability reduction techniques, but
should not be applied rigidly. While categories are useful for providing guidelines, each UA is unique
and survivability should be considered in the context of its specific design and mission. These
survivability categories are not intended to establish recognized UA classifications.
􀂾 Small. UA with a gross weight less than 500 pounds, a wingspan of 20 feet or less and that operate at
altitudes below 10,000 feet and 100 knots. These UA generally support tactical requirements and
range from man-portable up to trucked systems. Examples include the Raven, Dragon Eye, Pioneer
and Shadow.
􀂾 Medium. UA with a gross weight between 500 and 5,000 pounds., a 20-60 feet wingspan and
generally operate at altitudes of 10,000-30,000 feet and below 250 knots. These UA primarily
support tactical engagements, but may also address operational (theater) or strategic requirements.
The systems are airlifted or transported in specialized containers. Examples include the Predator and
Fire Scout UA.
􀂾 Large. UA with a gross weight above 5,000 pounds, wingspan longer than 60 feet and that operate
above 25,000 feet and 250 knots. These UA are generally considered operational (theater) or
strategic assets. These systems can self deploy or, as with Global Hawk, can operate from CONUS.
UA with a mission to deliver ordnance in high-density threat environments, such as the J-UCAS, will
　
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