ZUMWALT Class Destroyer Systems Engineering Foundations for CG

ABSTRACT
Richard A. Dumas and Anthony Montano
ZUMWALT Class Destroyer Systems Engineering
Foundations for CG(X)
As the prime Mission Systems Integrator for the
Navy's next generation destroyer, the Zumwalt
Class Destroyer, Raytheon is responsible for
development and delivery of the ship’s mision
system design. This includes the Mission
System Equipment (such as Dual Band Radar,
MK 57 Vertical Launcher System), Software
(over 20M lines of delivered source code),
Mission System Performance, and Life Cycle
Sustainment. The program introduces new
technologies into the Fleet to provide the Navy
with a ship that fulfills requirements well into
the 21 st century. The sheer size of the effort is
also complicated by having numerous
geographically and organizationally diverse
companies involved in the development effort.
In an environment of fiscal scrutiny, cost and
schedule performance are the keys to
maintaining program viability.
CG(X) will face similar large-scale system-of
systems integration challenges, not to mention
fiscal challenges, which can benefit from the
approach used by the Zumwalt team. CG(X) can
benefit from a number of Total Ship Systems
Engineering initiatives and processes to ensure
its success as well.
The Zumwalt Class Destroyer's mission is to
dominate the littoral, multi-threat battlespace in
all warfare areas, operating seamlessly as an
integral member of the Expeditionary Strike
Force, predominantly the Sea Base. The
primary offensive mission for Zumwalt is to
provide deep strike, precision and volume fires
in support of distributed Joint and coalition
forces ashore. In addition, the Zumwalt Class
provides its own Air Defense (AD), Surface
Warfare (SUW) and Undersea Warfare (USW)
self-defense, and can effectively provide some
local area protection to the Group or Force.
Within each of these primary mission areas, as
well as other missions such as Information
Operations (IO), the Total Ship Systems
Engineering (TSSE) team develops a collection
of "Mission Threads" (use case descriptions) to
demonstrate an end-to-end view of each of the
ship’s misions. This mission thread
methodology was introduced for Zumwalt Class
to provide an integrated view across the Flight 1
design and served to assess completeness of
requirements by providing operational context
for evaluating the total system. The mission
thread development allows a process of
“discovery” of derived capabilities to fulfill the
overall mission for a ship and sailor perspective.
The threads tied together CONOPS,
Architecture, Manning, and Requirements and
were the springboard to the larger Integrated
Engineering Model (IEM) used across the
geographically distributed team to provide a
common development environment. This is
critical to providing the Navy with a common
model and language to describe the ship’s
missions. All TSSE contributors (across the
National team) develop their artifacts in a
common model. Expanding on the groundwork
laid by Zumwalt to include new missions such as
Maritime Missile Defense provides a clear and
proven method for CG(X) design development.
This system approach will align the CG(X)
teams and lead to consistency of artifacts as well
as improved efficiency in the integration,
management and control of products.
INTRODUCTION
Central to any large scale system-of-systems
development is an underlying systems
engineering foundation to relate the various subsystems
to both the architecture and the
operators. Tying this together in an operational
context provides a clear vision to not only the
Copyright © 2008 Raytheon Company

development teams, but also to the end-users
who can view the end-to-end design within a
mission context. This provides a clear
advantage –it allows the end users a way to
evaluate the design completeness early in the
design process. The Zumwalt TSSE team
developed and then matured such a foundation
that is directly applicable, and more importantly
re-usable, to the CG(X) design team as the next
beneficiary in the "Family of Ships" strategy set
forth by the Navy. The “Family of Ships”
strategy allows the Navy to maximize re-use
from current investments and minimize new
development time and costs, and therefore
minimize any disruptions while transitioning
from production of Zumwalt Class Destroyers to
the CG(X). The TSSE process is a
recommended contributor to support the “Family
of Ships” development paradigm. The lessons
learned during this maturation period are now
incorporated into a team wide process resulting
in a product known as the Integrated
Engineering Model (IEM).
The need for an IEM was realized early in the
TSSE development and was a key enabler to
provide the team with a common tool to create a
Figure 1 - The Zumwalt Mission Systems Design Process
System Release Vision
- Joint Doctrine, ORD, CONOPs
-Drives Mission Threads and SRSs
•“MSLDA ”Mission
Threads
•Element Level
•Requirement Mapping
•Algorithm
Characterization
DOORS
Requirements
Object/Activity Links
DDG 1000 Rose
IEM
Element and
Component Level
Modeling
Information Flow
Traceability
singular artifact that relates architecture,
requirements, design and crew to each other in
order to understand the allocation of functions
and capabilities cross the system. The dominant
factor in this challenge was showing how the
Zumwalt design operates with increased
automation and a significantly reduced crew size
(120 ship's company vs. 348 in a DDG 51 Flight
IIA destroyer). The resulting IEM Process
integrated the efforts of a distributed team,
focusing on tying the critical pieces of the
design, as prioritized by the set of specified
performance parameters in the Operational
Requirements Document (ORD), into a cohesive
product. This resultant product is known as
Mission System Design (Figure 1) and has as its
core the IEM. The IEM allows the TSSE team to
decompose capabilities from a mission thread
perspective to detailed software requirement
specifications. The goals of a Mission System
Design include:
•Use a mission perspective to ensure
completeness and correctness of a design
that articulates what the system needs to
provide to support the naval warfighter
Integrated Task
Repository
•Sequence Diagrams
•Components/Ensembles
as Lifelines
ADDs
WSM
Watchstander
Model
Watchstander Loading
Preliminary Screen Design
DDG 1000 RoseRT
•Ensemble State
Machines
•Algorithms
Performance
Assessments
SRSs

•Establish the completeness of requirements
and interfaces while driving sub-system
product team designs consistent with the
overall Mission System Design
•Define all operational manning crew tasks
consistent with mission objectives
• Identify common capabilities and services
across mission areas, crew tasks, and subsystems
• Provide a Flight 1 vision for spiral software
development process
Zumwalt's TSSE team took the challenge of
reduced manning head on by including the crew
in the IEM. Thousands of tasks were identified
for crewmembers in the mission thread activity
diagrams, and each of the identified tasks
underwent a “task analysis” whereby numerous
attributes of each and every task were identified.
Results of the task analysis were documented in
the Human System Integration (HSI) Task
Repository, and includes information such as
which crewmember performs the task, the
knowledge, skills, abilities, and tools needed to
perform the task, task priority and criticality,
task duration, attributes associated with visual,
cognitive, auditory, and psychomotor workloads.
This modeling within the IEM provides a means
to verify crew size and workloads by
watchstation. It also provides a method to
define areas where automation can provide
potential alleviation in workloads.
Another Zumwalt Systems Engineering tool that
has provided ship level analysis (Key
Performance Parameter (KPP) and Measure of
Effectiveness (MOE)) capability is the Multi-
Mission Analysis Tool (MMAT). Based on the
IEM artifacts, MMAT is a simulation of the
Zumwalt Total Ship Computing Environment
(TSCE) core applications needed to evaluate
system performance, as well as models of the
mission systems equipment such as the Dual
Band Radar (DBR) and Advanced Gun System
(AGS). CG(X) will also have a need for this
level of simulation to support trade studies,
performance analysis, requirements analysis,
and design analysis. The modular design of the
model allows for easy integration of CG(X)
design, threats, and tactics.
APPROACH
Integrated Engineering Model
Modification or re-use of the Zumwalt IEM
artifacts for expanded or new CG(X) operational
capabilities begins with the Mission Thread Use
Case Descriptions. The mission thread use case
descriptions (Figure 2) are developed using
Universal Modeling Language (UML) activity
diagrams by which functionality is allocated to
system elements based on the capabilities called
out to support an end-to-end mission. All
"swimlanes" in the activity diagram are system
elements (i.e. sub-systems within the system
architecture), crew members, or external actors
(i.e. actors outside the system). In Zumwalt,
elements are developed within Integrated
Product Teams and are comprised of both
hardware and software configuration items. The
diagrams depict a logical behavioral flow as well
as necessary decision logic to execute a mission.
The diagrams call out any necessary preconditions,
as well as state and mode changes
using the notes or comment feature of the UML
tool. In addition to behavioral flow depictions,
the diagrams contain time and other
performance budget allocations, data flow, and
watchstander task information. The activity
diagrams are linked to system requirements and
interfaces to provide rationale and assess
completeness of the design.
Actor Element
Activity
Mission Thread Use Case Description
(For System)
Element
Activity
Element
Element
Activity
Element
Element
Activity
Figure 2 –Mission Thread Use Case Description
The "logical behavioral flow" in these Mission
Thread Use Case Description diagrams is in fact
the system Concept of Operations (CONOPS)
for that particular mission expressed as a UML
artifact.

Expansion to CG(X) missions, such as Maritime
Missile Defense (MMD), would involve
extending the existing Zumwalt diagrams as
shown in Figure 3. Swimlanes in the CG(X)
architecture represent reuse of Non-
Development Item (NDI) sub-systems including
the Zumwalt Total Ship Computing
Environment (TSCE) core software comprised
of Command and Control, Weapons Control,
Communications Control, Sensor and Vehicle
Control, and Engineering Control. Re-use of
Zumwalt TSCE Core also provides significant
risk reduction to meeting CG(X) manning goals
since the Human Computer Interface (HCI),
based on the crew tasks resulting from the levels
of automation delivered by TSCE software,
resides within the TSCE Infrastructure. New
sub-system capabilities identified in these
system-level use case diagrams can then be
further decomposed following the IEM process.
Key external systems that would be incorporated
in these diagrams would include, for example,
sea based tracking systems that provide targeting
data to CG(X) or other FORCEnet enablers of
the warfighting capability in CG(X). The
Figure 3 –Tailoring a Zumwalt IEM Artifact for CG(X)
resulting work products are UML artifacts that
are linked to requirements and describe the
CG(X) functional baseline and new (or
modified) software requirement specifications
(SRS) and Architecture Description Documents
(ADD) meeting the new and legacy interfaces
and logically integrated into the overall system
design.
Multi-Mission Analysis
As stated previously, another Zumwalt systems
engineering tool for CG(X) reuse builds upon
the CG(X) IEM foundation and that is the Multi-
Mission Analysis Tool (MMAT). MMAT is
comprised of two major simulation components
–the Mission Systems Logical Design
Simulation (MSLDS) and the System Effective
Simulation (SES). Figure 4 shows a high level
representation of MMAT.
The MSLDS is based upon IEM artifacts that
characterize the Total Ship Computing
Environment (TSCE) system design while SES
contains all the non-core system and ship
models, threats, environments, geography, and
simulation control. Because the core of MMAT

DD(X)-SES (FLAMES)
Threats
Cooperating
Forces
Sim Control: Time, Start/Stop/Step & Logging
is developed from the Zumwalt IEM, there is a
strong correlation and confidence between the
model and the tactical design. The modular
nature of MMAT facilitates growth for new
threats encountered by CG(X), as well as
incorporation of any new sub-systems needed to
meet the ship's required operational capabilities.
MMAT supports significant trade studies to
include the sizing of the radar suite to meet the
MMD mission as well as establishing the right
Radar Cross Section requirements for the ship.
By incorporating the full breadth "system of
systems" capabilities brought to bear in
completing an MMD engagement within the
simulation, the CG(X) team can establish the
minimum performance needed within CG(X)
sub-systems to meet the overall MMD mission
requirements.
CONCLUSION
Scenario
Environments
DD(X)
Ship and
Combat
Systems
Geography / Terrain
Figure 4 –Multi Mission Analysis Tool (MMAT)
Seventeen years after the Navy began to develop
the ship’s operational requirementsfor DD(X),
the U.S. Navy’s Zumwalt Class Destroyer is
entering production as the centerpiece of the
“Family of Ships” plan and is on-track for
delivery to the fleet in 2013. Reuse of existing
Zumwalt systems engineering products such as
MMAT and the Integrated Engineering Model
would provide a solid foundation for CG(X)
I/F
G/W
MMAT
Interface
Gateway
MSLDS (RTRose)
development and should significantly shorten
the time needed to define a functional and
allocated baseline for CG(X). Investment in
Zumwalt TSSE processes and lessons learned
will be critical to CG(X) success.
REFERENCES
DD(X)
C2, SVC,WCE
& Ship Control
(w/ Crew
allocations)
Start/Stop/Step
& Logging
Integrated Engineering Model (IEM) Process
Work Instruction, DDG 1000 Program, June 13
2006
Joint Defense Capabilities Study, Final Report.
Joint Defense Capabilities Study Team, January
2004
Systems Engineering Management Plan -
Revision E, DDG 1000 Program, June 2 2006
ACKNOWLEDGMENT
The authors wish to thank Stuart Karon, CDR
Mike Smith, USN and Daniel Gurry for their
contributions in identifying source material and
reviewing the draft.
____________________________________
Richard Dumas is the principal author and is
an employee of Raytheon Company, Integrated
Defense Systems. He retired from the Navy in
2003 as a Commander in the Engineering Duty
community after serving 21 years. His sea
assignments include Auxiliaries Officer and
ASW Officer in USS Harry W. Hill (DD 986),

Engineer Officer in USS Gary (FFG 51) and
Engineer Officer USS Philippine Sea (CG 58).
His significant shore duties include Air
Dominance Officer in PMS 500 and Air
Dominance Department Officer at Naval
Surface Warfare Center, Pt. Hueneme Division.
He obtained his bachelor's degree in physics at
the University of Utah and his master's degree
in physics at the U.S. Naval Postgraduate
School.
Anthony Montano is a Senior Systems
Engineer who has worked exclusively on the
Zumwalt Class Destroyer Program since joining
Raytheon in 2003. Anthony is currently the
Sense Segment Software Requirements Lead
responsible for development of the Sensor and
Vehicle Control software requirements
specification. His role has recently expanded to
guide the Unified Modeling Language modeling
efforts of the large and geographically diverse
Zumwalt Systems Engineering Team. Anthony
joined Raytheon with a bachelor's degree in
Electrical and Computer Engineering from
Worcester Polytechnic Institute.