A Bluefin-12 based system soluti

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A Bluefin-12 based system soluti Powered By Docstoc
					Bluefin-12 UUVs for SMCM /UUV-2                                        Bluefin Robotics Corp. and QinetiQ Ltd.

    A Bluefin-12 based system solution for the US Navy's
   Surface Mine Counter-Measures Unmanned Underwater
        Vehicle Program: Increment 2 (SMCM/UUV-2)
                            Scott Willcox, Joseph Bondaryk, and Knut Streitlien
                                        Bluefin Robotics Corporation

                                           Chris Emblen and John Morrison
                                                      QinetiQ Ltd.

1 Introduction
In August 2006, Bluefin Robotics was awarded a contract by the US Navy to deliver a state
of the art UUV-based mine countermeasures system for deployment and operation from the
Navy’s USS Avenger (MCM-1) Class of Surface Mine Counter-Measures (SMCM)
platforms, as well as ships of opportunities. The goals of the SMCM/UUV-2 program are to
develop tactics, techniques, procedures, and employment concepts for medium sonar range
UUVs with high quality imaging; characterize the capabilities of next generation sonar
sensors; and mitigate ship integration risks.
Each SMCM/UUV-2 system is comprised of:
• two 12.75”-diameter Bluefin-12 UUV platforms with removable battery and data
• all support equipment for on-deck servicing and maintenance, deck handling, launch and
   recovery, and small boat operations;
• operator workstation with up to 10TB of removable storage;
• post-mission analysis (PMA) workstations with multiple high resolution displays; and
• training, support, and system spares as needed.
As its primary payload sensor, each SMCM/UUV-2 vehicle carries a state of the art dual-
frequency synthetic aperture sonar (SAS) made by QinetiQ Ltd. The SAS will provide 1"x1"
resolution in the High Frequency band and 3"x3" resolution in the Low Frequency band to a
range of greater than 60m per side. Each vehicle is furnished with a Removable Data Storage
Module (RDSM) so that raw sonar data can be physically removed from the vehicle, thereby
eliminating long data downloads and enabling rapid on-deck vehicle turnaround. Signal
Processing for SAS image formation and contact calling will be accomplished on the PMA
workstation. In addition to the SAS, the SMCM/UUV-2 vehicles also carry CTD, turbidity,
and current measurement sensors for in-situ environmental assessment.
This paper gives an overview of the Bluefin-12 UUV platforms upon which these systems are
based, the QinetiQ SAS system that is the primary mission sensor, the operator software tool
suite, and a brief discussion of the SMCM/UUV-2 program status.

2 Bluefin-12 AUV Platform
The Bluefin-12 is a light-weight torpedo form factor UUV. Figure 1 shows a Bluefin-12
UUV and Tables 1 through 4 give an overview of some of the characteristics of the vehicle.
Figure 2 shows the mechanical layout of the SMCM/UUV-2 vehicles. The Bluefin-12’s
constituent elements are laid out in a free-flooded shell, interconnected by underwater cables.

Distribution Statement A: public release, distribution is unlimited.                                         1
Bluefin-12 UUVs for SMCM /UUV-2                                           Bluefin Robotics Corp. and QinetiQ Ltd.

The hallmarks of Bluefin UUVs are
their modular design and their use of a
rugged, flexible, free-flooded archi-
tecture. This design choice stems from
Bluefin’s central aim of building not
just a collection of UUVs, but a UUV
tool kit—a collection of interoperable
modules that enable the user to tailor
the UUV system to meet the needs of a
given operational setting. Our vehicles
must be easy to launch and recover,
easy to program, and easy to upgrade.
We incorporate our “design for the
operator” philosophy in all aspects of
our systems to ensure their success.    Figure 1: The Bluefin-12 UUV is a modular plat-form that
                                                              supports several different payload modules.
2.1 AUV Architecture
The Bluefin-12 UUV is designed around a modular mechanical and electrical architecture
built into a rugged and lightweight free-flooding structure. There are three distinct and very
important advantages to Bluefin’s modular, free-flooded approach. First, it facilitates the
addition of new features and capabilities into the AUV platform. The entire payload section
of the Bluefin-12 can be swapped on-deck in under and hour, giving the SMCM/UUV-2
system the ability to carry out different types of missions without requiring a significant
modification to the existing systems.
Secondly, Bluefin’s modular architecture improves operational availability and reliability.
Our reliance on self-contained modular subsystems connected by underwater cabling allows
any individual module to be swapped on deck in a matter of minutes. UUVs are complex
systems operating in a corrosive and energetic ocean environment and occasional subsystem
and component casualties are to be expected. Bluefin’s modular subsystems allow the
                                            repairs of most elements of the AUV
operator to conduct at-sea replacementTable 1: Characteristics of the Bluefin-12system, thereby
                                 Feature                 Description
improving system availability and robustness. Each component of the vehicle is separately
                                                          quickly replaced in payload
testable under realistic operating conditions, and can be84” to 150”; varies withthe field, yielding
excellent overall system reliability and availability.
                                 Diameter                12.75”
                                               Weight in air                 300 to 500 lb; varies with payload
Finally, Bluefin’s open                        Fresh water Buoyancy          15lb
architecture enhances the                      Speed                         0.5-5kts
operational capabilities of                    Endurance                     10-23 hours (speed dependent)
the SMCM/UUV-2 system.                         Energy                        Removable, pressure-tolerant Batteries
The removable battery and                      Operating Depth               200m
                                               Navigation                    IMU or INS, Compass, DVL, GPS
data storage modules allow
                                               Communications                Acoustic Modem, RF Modem, Iridium
the Bluefin-12 vehicles to                                                   Satellite Comms
be turned around on deck in                    Safety Systems                Leak detectors, acoustic & RF aborts,
30 minutes or less. This                                                     watchdog timers, radio directing finding
capability increases the                                                     beacon, strobe light, drop-weight
operational duty cycle of                      Payloads                      Numerous Payload modules including:
                                                                             • Conventional Sidescan Sonar (SSS)
Bluefin AUV systems to
                                                                             • Synthetic Aperture Sonar (SAS)
between 95% and 98%.                                                         • Burried Object Search Sonar (BOSS)
This      represents     an                                                  • Forward Look Sonar (FLS)
enormous       improvement                                                   • Water Properties: CTD, OBS, etc.
over conventional UUV

Distribution Statement A: public release, distribution is unlimited.                                                    2
Bluefin-12 UUVs for SMCM /UUV-2                                        Bluefin Robotics Corp. and QinetiQ Ltd.

systems wherein data must be downloaded over Ethernet and batteries must be recharged in
situ. Historical data with such systems indicate maximum operational duty cycle of between
33% and 50%. Given that the various UUV systems have similar coverage rates, the
improved operational duty cycle of the Bluefin systems enables the SMCM/UUV-2 system to
survey large areas two to three times faster than competing AUV platforms. This is a
significant advantage to the MCM Commander and has the potential to save lives.
                                       Table 2: Summary of Bluefin-12 Safety Systems
 Feature                                       Description
 Acoustic tracking                                Woods Hole μModem
 Aborts                                           Via the Comms Deckbox over acoustic or RF Modem channels
 Emergency weight release                         Burn wire activated drop weight
 Emergency Acoustic Tracking                      Acoustic transponder with 1 month battery backed operation.
 Visual tracking on surface                       White light or IR Strobe
 Radio Direction Finder                           RDF transmitter with own battery
 Emergency power                                  Rechargeable battery pack for drop weight, RDF, and strobe.
                                      Table 3: Bluefin-12 Communications Capabilities

 Feature             Description
 Acoustic            A Woods Hole μModem supports low data rate messaging of vehicle and mission
 Modem               status as well as operator commands. Also supports acoustic tracking of the UUV.
 Iridium             High-rate data in burst mode. Vehicle status, tracking, and limited data transfer.
 RF Modem            Radio Modem supporting rates of up to 128kbps over 1-3 nmi (LOS). All capabilities
                     above plus UUV data transfer. Primarily used for mission start, status when on the
                     surface, and vehicle check-outs on the deck.
 Ethernet            Back-up system for on-deck vehicle check-outs and diagnostics.
 Deckbox             The ship-board side of each of the above communications systems is integrated in
                     the Bluefin Communications Deckbox, a small, light-weight, and water-tight piece of
                     the standard suite of operations equipment.

                Figure 2: Layout of the Bluefin-12 UUV with an integrated QinetiQ SAS Payload

2.2 Availability, Reliability, and Maintainability
To address the difficult programmatic issues of reliability, availability, in-field maintenance,
and long-term supportability, Bluefin’s UUV platforms are based on a common set of
subsystem modules. The modules are contained in individual pressure vessels or pressure
balanced oil-filled housings and each module can be easily removed and replaced in the field
should a platform problem arise. Since the same modules are used across a variety of
platforms, the life-cycle costs associated with these platforms is lowered by the use of a
common spare parts depots for multiple systems. Once an operator has been trained to

Distribution Statement A: public release, distribution is unlimited.                                            3
Bluefin-12 UUVs for SMCM /UUV-2                                        Bluefin Robotics Corp. and QinetiQ Ltd.

operate and maintain one of our Bluefin-9, Bluefin-12, or Bluefin-HAUV platforms, they
require very little additional training to operate either of the other two systems.

                        Table 4: Representative UUV Modules on the Bluefin-12 UUV.
  Module         Description
 Tailcone        The Bluefin tailcone provides propulsion and exceptional dynamic control of the UUV in a
                 compact, robust structure. It has several safety features including over current and over
                 voltage protection, leak sensing, watchdog timeout, and oil level sensing.
 MEH             The main electronics housing (MEH) contains the UUV’s control and navigation systems,
                 houses electronics for the sensors, and performs the power switching and power
                 conditioning functions.
 Battery         Bluefin-12 has pressure tolerant rechargeable batteries that can be replaced in a matter
                 of minutes for fast turnaround. Each battery has monitoring circuitry that protects the
                 battery from overload, leaks, over-temperature, over-charging and over-discharging.
 RDSM            Sonar and UUV data are stored in a stand-alone removable data storage module
                 (RDSM). By physically removing and replacing this data module, the time consuming
                 process of transferring large data volumes is eliminated.
 Comms           The Iridium modem with its encryption hardware, the P-Code GPS unit, and a back-up
                 battery will be packaged in separate pressure housing. This allows security sensitive
                 components to be easily removed from the vehicle and stored when not in use.
 Antenna         The antenna mast is an evolution of the Bluefin standard design that incorporates the
                 Iridium antenna along with GPS, strobe, RF modem, and an RDF beacon. It is an
                 exceptionally robust package with a solid state molded antenna head and a streamlined
                 compliant fin.

The modular characteristics of all the Bluefin system designs provide the best flexibility in a
fielded system to perform rapid maintenance and repairs and to keep critical assets
operational and where they are most needed.
2.3 Payload Modularity
Payload sensors can be separated into two types: simple instruments and major systems. The
former consists of CTDs, optical sensors, etc. They use regulated power that is switched and
monitored from the Power Board in the main electronics housing and communicate to the
vehicle host computer via a dedicated serial port. Major systems would be sonars and similar
complex sensors. These communicate to the vehicle computer over an Ethernet connection
and are supplied raw battery power which the payload regulates internally. The electrical
interface provides raw battery power of up to 8A at 30V through a standard payload
connector. All navigation, sensor, and control information between the payload and MVC is
sent using a TCP connection over the onboard Ethernet network. The Bluefin-12 UUV
supports the simultaneous operation of two major payload systems.
In addition to the primary payload(s), the Bluefin-12 platform carries a variety of secondary
payload sensors for standard oceanographic/hydrographic measurements. The secondary
payload sensors are described in the Error! Reference source not found. below.
2.4 Navigation
Among the commercial UUV providers, Bluefin is the recognized leader in both low-cost,
dead-reckoned and high-accuracy, INS-based navigation systems. We have spent several
years developing and refining our UUV navigation algorithms to the point that the real-time
navigation accuracy of Bluefin’s standard dead-reckoned navigation system now exceeds the
performance of some commercial INS systems. The error growth of our standard dead-
reckoned navigation system is less than 0.5% of DT (3σ) in real-time and less than 0.2% of
DT in post-processing (2σ). Our standard navigation solution consists of:

Distribution Statement A: public release, distribution is unlimited.                                         4
Bluefin-12 UUVs for SMCM /UUV-2                                        Bluefin Robotics Corp. and QinetiQ Ltd.

     •     a magnetic compass,
     •     a RLG-based IMU,
     •     a 300 or 600 kHz DVL,
     •     a WAAS differential, 12-channel GPS receiver, and
     •     a pressure/depth sensor.
Data from the above sensors
are processed in real-time
using     two      proprietary
processing techniques that
allow Bluefin to observe and
model the error sources and
then remove these errors
from the real-time navigation
solution. After the mission is
completed, and before sonar
imagery is reviewed for
contacts, an a-causal filter
can further improve the
accuracy of the navigation
solution. The post-processed
navigation           accuracy
determines the accuracy of
contact locations, while the
real-time accuracy drives the                   Figure 3: Bluefin real-time navigation accuracy histogram presents
spacing of tracklines to                        maximum per trackline navigation errors as a percentage of the
ensure     100%      coverage                   distance traveled on each trackline. Real-time navigation
                                                performance is better than 0.5% of DT, 3σ (i.e., 95% of
without holidays. The real-
                                                occurrences), and post-processed accuracy is better than 0.2% of
time       accuracy       also                  DT, 2σ (83% of occurrences). These statistics are derived from 185
determines the maximum                          mission tracklines surveyed during a recent Sea Acceptance Test
distance that the UUV can                       (SAT) for the U.S. Navy.
survey before a GPS fix is

3 QinetiQ Simultaneous Dual-Frequency SAS
As the primary payload of the SMCM/UUV-2 System, QinetiQ is providing a superior
capability, dual frequency synthetic aperture sonar (SAS) which is proven, reliable, cost-
effective and designed to be flexible and extendable, covering both current and emerging
military requirements. The technology has been extensively employed at sea in multiple
vehicles, including the Bluefin-built Gambit UUV that was developed as part of the “US/UK
Collaboration on UUVs for MCM”, Figure 4.
The QinetiQ payload, integrated with the Bluefin vehicle (see Figure 2), provides a vehicle
capable of performing sorties with high area coverage. Utilizing a simultaneous dual
frequency broadband SAS, this system is capable of detecting bottom and partially proud
mines to a range of 100m, as well as offering a capability against shallow buried targets.
The system consists of a 60cm array with 24 receive array elements per side. From our
extensive at sea-testing program, QinetiQ has demonstrated that the use of additional
elements significantly improves the overall robustness of the sonar. By utilizing a
configuration that is theoretically capable of achieving a 0.5” resolution, QinetiQ can ensure

Distribution Statement A: public release, distribution is unlimited.                                             5
Bluefin-12 UUVs for SMCM /UUV-2                                        Bluefin Robotics Corp. and QinetiQ Ltd.

the consistent and robust production of a
1” resolution across a wide range of
environmental conditions. The array
design ensures close control of transmit
and receive beam patterns reducing the
susceptibility to multipath, while the
increased number of phase center overlaps
realized by the longer array with smaller
element spacing allows for effective
filtering of the motion data, further
excluding the destructive multipath
effects. The increased number of phase
centers allows the QinetiQ motion Figure 4: Operations with the Bluefin-21 Gambit UUV
                                           for the UK Royal Navy have helped shape the
compensation system QDAVA, which development of the QinetiQ SAS payload
integrates information from the displaced
phase center antenna (DPCA) algorithm, vehicle motion sensors, and acoustic modeling, to
produce higher accuracy results than obtainable from a high grade INS. This provides the
ability to extend the path reconstruction capability and hence the range/resolution of the
system. The increased overlap and QDAVA also reduces the reliance of the SAS on high
platform stability.
QinetiQ’s SAS processing algorithms have been proven through the successful completion of
hundreds of at-sea runs with the Gambit UUV for both research trials and operations for the
UK Royal Navy. Long range, high quality SAS images have been created at ranges greater
than 200m in 14m of water using the QDAVA system and array designed to reduce the
effects of multipath. For example, Figure 5 shows a target at a range of 120m, with the
shadow clearly identifying its conical shape. Figure 6 shows a SAS image of a target at 75m
with the clear shadow identifying it as a non-mine (approx. 1.5 meter diameter cable reel).
The sonar receive array is
based on broadband 1:3
composite             technology
pioneered by QinetiQ. This
system is light and compact
making it ideally suited for
                                  Figure 5: The system resolution allows a detailed look at both
integration on a 12” diameter target and shadow, even at long ranges.
UUV. A fully digital data
acquisition system is controlled using a single FPGA ensuring close synchronization of both
transmit and receiver clocks, thereby ensuring the fidelity of signal phase and amplitude
essential for high quality SAS processing. This flexible FPGA also supports the generation of
a number of pre-defined transmit waveforms including CW and FM. Base banding, anti-
aliasing filtering, and pulse compression operations are carried out by an additional FPGA in
each receiver module. Furthermore, the receive module is designed to ensure high levels of
noise and EMC rejection by adjacent system inversions to cancel of common mode signals.

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Bluefin-12 UUVs for SMCM /UUV-2                                                        Bluefin Robotics Corp. and QinetiQ Ltd.

Figure 6: The QinetiQ SAS solution offers excellent large area views combined with superb resolution for
high performance CAD/CAC. The shadow in this image clearly shows that the 1m object is a non-mine.

4 Operator Software
The Bluefin/QinetiQ integrated operator tool suite provides a comprehensive interface for all
phases of system operation. This set of graphical interfaces is designed to simplify all
operational and maintenance procedures and lead the operator through required procedures,
such as pre-dive vehicle checks. The SMCM/UUV-2 system features an integrated user tool
suite, including integrated post mission analysis (PMA).
Open-Architecture                                                                                 Main Vehicle Computer                    Sensors &
Bluefin has made simple, intuitive,                                      Computer
                                                                        Operator GUI
                                                                                            Control SW             SW Drivers               Payloads
                                                                                            Autonomy                  INS                  INS Sensor
operator tools a cornerstone of our                                        Suite
                                                                                            Navigation                DVL                  DVL Sensor
UUV efforts. The development of                                          Simulator
                                                                                             Dynamic                Acoustic
                                                                        Development          Control                Comms        RS232       Modem
the operator tool suite has simplified                                  Environment
the user experience, empowering the                                     Module Dev.
                                                                                            Supervisor                SAS
                                                                                                                                           SAS Payload

operator to maximize their effective-                                   Driver Dev.
                                                                         3rd Party
                                                                                           Data Logging               CTD
                                                                                                                                           CTD Sensors

ness with the UUV system. All                                            Simulator
                                                                         3rd Party

                                                                        Module Dev.         3rd Party               Tailcone                Tailcone
components of the operator software                                                          Module
                                                                                            3rd Party
                                                                                                                    Assembly     RS485      Assembly
                                                                                                                    3rd Party              New Sensor
are based on our state-of-the-art                                                            Module                  Driver      RS485     or Payload

Huxley vehicle software engine and                                     SOMA Bus
                                                                                           SOMA Bus
our Stream-Oriented Messaging                                   Off-Board Code                            On-Board Code & Hardware

Architecture (SOMA). Huxley and                               Figure 7: Bluefin’s Stream-Oriented Messaging Archi-
SOMA provide a powerful paradigm                              tecture (SOMA) is a published interface standard
for open architecture development,                            recognized by the US Navy. SOMA supports Bluefin’s
including user interface develop-                             open architecture paradigm, allowing customers and 3rd
ment, Figure 7. Users are presented                           parties to develop code for execution on Bluefin’s vehicles
                                                              or integration with our Operator GUI Suite.
with a seamless suite of operator

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Bluefin-12 UUVs for SMCM /UUV-2                                        Bluefin Robotics Corp. and QinetiQ Ltd.

tools that they can navigate based on their operational needs. Third-party tools (including
user interface components) are integrated with a single look-and-feel and unified approach
for the user experience. In this manner, the team is capable of leveraging the best-of-breed
user interface solutions for various tasks (e.g., SAS imaging, mosaicing, tracking, contact
management, planning, and vehicle monitoring) while maintaining a unified feel for the
interface that is intuitive and tailored to the concept of operations for the MCM mission. The
components of the operator tool suite are described in detail below.
Mission Planner
Bluefin’s Mission Planner, Figure 8, provides a powerful graphical tool for mission planning
and vehicle redirection. Complex mission plans, including multiple surveys and support for
multiple vehicles, can be built up from basic components, such as rectangular surveys. All
planning takes place on top of a chart-based view, which can incorporate raster or digital
charts or other imagery (e.g. satellite imagery). A variety of data layers, such as bathymetry
or sonar mosaics from previous missions, can be displayed to assist with detailed mission
planning or refinement. Planning may be carried in either stand-alone mode or while attached
to a specific vehicle or set of vehicles. Operators can specify safety settings and operational
constraints based on mission mode (exercise or tactical operation) or specific mission
requirements. Vehicle recovery points and return plans can also be specified.
The Dashboard provides a comprehensive interface to the vehicles. Vehicle status is readily
apparent, including any explanations for unexpected behavior (for example, reasons for an
abort). Vehicles may be tracked against a chart-based interface, including indications of the
ship position, mission plans, and a variety of operator-specified annotations. The Dashboard
provides a dynamic communications gateway to online vehicles, automatically shifting to the
channel with the highest available bandwidth. A variety of specialized diagnostic interfaces
are included to aid in the preventative and corrective maintenance procedures for each sensor
and subsystem.
Mission Data Manager
The Mission Data Manager (MDM) provides automatic data management and post-
processing. Data is automatically downloaded and archived when an RDSM is attached to the
Operator Station computer. Data is post-processed (including re-navigation and reformatting)
and provided to the PMA Station computer for SAS processing. The Mission Data Manager
also provides a database for managing SAS images, mosaics, contacts, and environmental
Post-Mission Analysis (PMA)
The PMA processing station provides each SMCM/UUV-2 system with the capability to
display, analyze and report information on mine-like contacts (MILCs) at twice real-time,
with a stretch aim of four times real-time. This intuitive set of interfaces is integrated with a
consistent look and feel. On the PMA station, sonar data is displayed at high resolution for
accurate review, Figure 8. Vehicle data, contact snippets, and mosaiced sonar data are
combined in a chart-based display to provide a comprehensive overview for the operator.
Data is exported to MEDAL and EPMA systems. For the SMCM/UUV-2 program, this
system will also be interfaced to PMA2005 for SAS image-based CAD/CAC processing.
After a UUV mission, the PMA system retrieves recorded data from the removable data
storage module (RDSM), which includes information on the contacts produced from the on-
board CAD/CAC. The system immediately begins SAS processing around these targets,
increasing the effectiveness and speed of the initial analyses. This initial processing generates
a series of image snapshots for processing using the PMA2005 CAD/CAC algorithms.

Distribution Statement A: public release, distribution is unlimited.                                         8
Bluefin-12 UUVs for SMCM /UUV-2                                        Bluefin Robotics Corp. and QinetiQ Ltd.

Figure 8: The Bluefin Operator Tool Suite provides a variety of intuitive user interfaces to help manage
all phases of system operations and maintenance, including planning, mission monitoring, data
management, post-mission analysis, data export, and vehicle maintenance.

Full swath processing of both LF and HF data takes place with the output displayed on two
separate screens controlled by the operator. All information displayed is fully geographically
referenced to the WGS-84 standard, with functions provided for object zooming,
measurement of contact size (length/width) and height above the ground from the shadow.
Geographically referenced information utilizes post-mission re-navigation processing to
maximize the positional accuracy of detected targets. Processed sonar information is sent in
CSDT format to the PMA2005 system, with identified MILCs forwarded to MEDAL in the
required message format. At the same time, sonar images are forwarded in the universal sonar
image processing system (UNISIPS) format to an EPMA workstation for environmental
The PMA station also provides an automated sonar mosaicing and seabed classification
capability providing the MCM command team with an overall picture of the mission sortie
undertaken by each SMCM/UUV-2 system. The benefits in terms of the improved situational
awareness provided by these displays to operators and decision makers alike has been proven
in numerous Royal Navy surveys, UUV, and diver operations.

5 SMCM/UUV-2 Program Status
The SMCM/UUV-2 system had a successful Preliminary Design Review (PDR) in December
2006. The program is currently on schedule in its detailed design stage. Modifications to the
existing Bluefin-12 platform to tailor it to the SMCM/UUV-2 requirements include the
incorporation of a 1TByte RDSM, integration of a Kearfott INS system, integration of a
military GPS system, hardening of the system to meet Information Assurance guidelines, and
the design and integration of a forward fin module to minimize crab angle in high-current
A Critical Design Review (CDR) with the customer is planned for the end of June 2007.
Parts procurement, build and test phases will follow. First articles should be in the water in
January 2008. The three systems will have a phased delivery March 2008 through end of
April 2008.

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