Intelligence, Surveillance, and Reconnaissance - Spawar

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INTELLIGENCE, SURVEILLANCE, AND RECONNAISSANCE
of the discovery and invention projects within the
Seaweb Initiative. Feedback from Navy commanders
indicates that fleet acceptance of Seaweb-based
systems critically depends on the incorporation
of TRANSEC. Achieving TRANSEC as an integral
feature of telesonar-based networking will foster the
extension of Seaweb to clandestine missions and
stealthy platforms, all of them interoperable with
the aforementioned existing applications.
Compared with traditional point-to-point acoustic
communications approaches, telesonar TRANSEC
inherently derives from the relatively low transmit
power levels and high frequencies made feasible by
Seaweb network routing and repeater nodes.
Telesonar link-budget analysis [16] is aiding the
design of an evolving Seaweb physical layer incorporating
electronically steered directional transducers
[17], higher acoustic frequencies, increased spectral
bandwidth, spread-spectrum signaling [18 and
19], and power control.
CONCLUSION
Undersea, off-board, autonomous
systems will enhance the
war-fighting effectiveness of
submarines, maritime patrol aircraft,
amphibious forces, battle
groups, and space satellites.
Wide-area sensor grids, leavebehind
multi-static sonar
sources, mine-hunting robots,
and AUVs are just a few of the
battery-powered, deployable
devices that will augment space
and naval platforms. Distributed
system architectures offer maximum
flexibility for addressing
the wide array of ocean environments
and military missions.
Transformation of undersea warfare
will result from the ability
of mission planners and theater
commanders to deploy an
appropriate mix of undersea sensors,
vehicles, and other devices
from a repertoire of evolving
component systems. Sea power
is achieved through the ability to
match a resource set to the ocean
environment and the mission at
hand. Robust, environmentally
adaptive telesonar modems
interconnect undersea assets,
OVER-THE-HORIZON
COMMAND CENTER
6 REPEATER NODES
NODE-TO-NODE SPACING
1.5-3.0 km
44°16.5'
44°16'
44°15.5'
44°15'
150
150
175
44°14.5'
150
63°16.5' 63°16' 63°15.5' 63°15' 63°14.5' 63°14' 63°13.5'
KILOMETERS
0 1 2 3
FIGURE 3. The October 2002 RDS-4 Seaweb network in the
Approaches to Halifax supported the RDS-4 Rapidly Deployable
Sensors Trials. Seaweb networking integrated U.S. and Canada
experimental autonomous ASW sensors deployed on the seafloor.
Gateway buoys supported FreeWave line-of-sight radio links and
Iridium satelite links to the shipboard command center.
Legend: – U.S. and Canada gateway buoys; H – U.S. Hydra
HLA sensor; K – U.S. Kelp VLA sensors; U – Canada UCARA
HLA sensors; – U.S. Seaweb repeater nodes.
2 RACOM BUOY GATEWAY NODES
3 AUV GLIDER MOBILE NODES
IRIDIUM SATELLITE
RADIO LINKS
CFAV QUEST
COMMAND
CENTER
FREEWAVE
RADIO LINKS
FIGURE 4. The February 2003 Q272 Seaweb network in the Eastern Gulf of Mexico included
three AUVs, six repeater nodes, and two gateway buoys. The experiment exercised Seaweb
ranging functions for tracking and navigating mobile nodes. The AUVs proved themselves
as effective mobile gateway nodes with telesonar, FreeWave, Iridium, ARGOS, and GPS.
175
K
H
150
K
U
150
U