Module: [LIBR_01]_SIGE XIII_Method Prop to Design Radars Topic: RESEARCH, DEVELOPMENT & INNOVATION Subject: A Methodology Proposal to Design Radars - Systems Approach Article by Antonio Sallum Librelato and Osamu Saotome, presented and published during the XIII SIGE. ITA, 27 a 30 de setembro de 2011. Scope: Abstract I. INTRODUCTION Motivations for the Systems Concepts Research (SCR) method II. BRIEF DESCRIPTION OF THE SCR METHOD Principles of SCR Phases of the SCR Purposes of SCR III. NRA - NEEDS AND REQUIREMENTS ANALYSIS Purposes of NRA Steps and Tasks of NRA IV. SCE - SYSTEMS CONCEPTS EXPLORATION Purposes of SCE Steps and Tasks of SCE V. SCD - SYSTEM CONCEPT DEFINITION Purposes of SCD Steps and Tasks of SCD VI. SRAA - SYSTEMS RISKS AND ASSURANCE ANALYSIS Purposes of SRAA Steps and Tasks of SRAA VII. CONCLUSIONS REFERENCES

1. ISSN: 1983 7402 ITA, 27 a 30 de setembro de 2011
A Methodology Proposal to Design Radars -
Systems Approach
Antonio Sallum Librelato1 and Osamu Saotome2
1 EThICS Engineering - Rua Prof. Maria Lima Cesar, 181, Ap. 12 - CEP 12216-141 - São José dos Campos - SP - Brasil
2 Instituto Tecnológico de Aeronáutica - Praça Marechal Eduardo Gomes, 50 – Vila das Acácias – São José dos Campos – SP - Brasil
Abstract  When creating new systems, it is In the reference [2], the system engineering processes
recommended that, before starting the engineering comprehend mainly the definition of the problem, needs,
development phases of the project, the concept phase be feasibility, functional and performance analysis, the
executed. The proposed Systems Concepts Research (SCR) operational and logistical requirements, resulting on the
method was structured by one of the authors1 and refers to system synthesis, analysis and design optimization.
the concept phase of the project life cycle, in special when The reference [3] presents the System Architecture
applied to systems based on complex and critical Development, comprising requirements, operations, behavior
technologies, like radar systems. Additionally to the usual and physical elements of systems.
specialized tasks of systems development, this method Reference [4] considers the importance of the systems
integrates the specialized tasks of systems and products and products assurance technologies, like quality, reliability
assurance. The objectives of this article are: safety, maintainability, and others, considering also their
• To present the steps and tasks of the SCR method; combined effects and influence on the system cost-
• To reinforce the advantages of doing it before the effectiveness and risks.
system development phase; and The reference [5] presents a methodology for radar
• The convenience and advantages of the integrated systems analysis, considering the systems, requirements, and
and simultaneous execution of the analysis of risks, parameters for the development of new radars.
cost-effectiveness and system assurance, as part of There is a consensus among those references that the
the SCR method. phase of system concept definition must be executed before
Keyword  research, assurance, radar. the beginning of the phase of system development, and that,
doing so, it will result on reducing costs and risks, with better
I. INTRODUCTION effectiveness of systems. Nevertheless, none of the
mentioned references establishes a clear integrated method to
Motivations for the Systems Concepts Research (SCR) do this, and that is the purpose of the present work..
method: The proposed SCR method was structured to create an
The project of complex and critical systems, like radars, is appropriate framework to permit the practical benefits of
submitted to challenging factors presented by the current those principles, by:
environment. These factors are the main motivations to adopt • Comprising all the tasks usually recommended by the
the SCR method, as follows [2]: references for the concept phase, as above, and
• Increasing systems complexities. • Additionally integrating the tasks necessary to assure
• Evolving technology changes. best results on the cost-effectiveness of systems,
• Extended systems life cycles. comprising:
• Shorter technologies life cycles. Management of:
• Constantly changing requirements. Systems and Products Assurance,
• More emphasis on “systems” (versus components). Risks,
Cost-effectiveness,
• Greater utilization of commercial off-the-shelf
Configuration,
(COTS) products.
Software Assurance,
• Higher overall life-cycle costs.
Rights and Penalties of Assurance and
• Increasing demand for mitigation and control of Warranties.
uncertainty and hazard risks during the development
• Engineering of:
phase, mainly when based on new and not well mature Quality,
technologies [4]. Reliability,
In the reference [1], the main tasks of the concept
Maintainability,
development comprise needs analysis, concepts exploration
Safety,
and definition. Security,
A. S. Librelato, a.sallum@uol.com.br, Tel +55-12-39418277. O. Saotome,
osaotome@ita.br, Tel +55-12- 39475818.

2. ISSN: 1983 7402 ITA, 27 a 30 de setembro de 2011
Human Factors, • Assure that a real and valid need exists, with at least
Supportability and logistics, one feasible solution to attend it.
Sustainability, • Define a valid set of operational, functional and
Verification and Validation, and performance requirements to be attended by the
Other analogous. concept.
By acting in advance to the development of systems and • Explore technologies and systems capable to fulfill the
products, the SCR creates opportunities for: needs and requirements.
• Consolidating the requirements, since the beginning of • Select the system concept that best accomplish the
the project studies. established needs, requirements, restrictions,
• Active participation of the main stakeholders on the assurances, and balance of cost-effectiveness.
project. • Planning the subsequent phases of development,
• Reduction of the future life cycle costs of the system. production, support, usage and discard of the selected
• Reduction of hazard and uncertainty risks. concept.
• Improvement of the effectiveness of solutions.
• Analysis and evaluation of the required and available III. NRA - NEEDS AND REQUIREMENTS ANALYSIS
knowledge and technologies for the execution of the
project. Purposes of NRA:
• Conscious and comparative selection of the most • Understand what the problem to be solved by the
adequate solution, from distinct alternatives. future system is.
• Reduction of the management and engineering efforts • Establish that a necessity for a new system really
to develop the system. exists and is valid.
• Direction and recommendation of actions to mitigate • Establish that the desired system is technically and
and control of risks, costs, and systems assurance. economically feasible.
• Elicit and analyze the requirements applied to the
II. BRIEF DESCRIPTION OF THE SCR METHOD project and to the system.
Principles of SCR: Steps and Tasks of NRA:
The SCR method comprises a series of interactive tasks. • Vision of Problem:
It will require specialized knowledge and skills on Description of the motivations, nature, magnitude,
management and engineering of systems, requirements, risks, and context of the main problem to be solved.
product assurance, costs and project planning and product Evaluation of the risks derived if the problem will
development. Depending on the specific conditions of not be solved.
procurement and supply of systems, the work share between • Needs Analysis:
client and manufacturer (or supplier) will vary. Anyway, the Description of the needs, goals and objectives to
complete composition of tasks is practically the same. be attended.
The SCR method brings great benefits on obtaining the Description of the suppositions and restrictions to
best solution for the needs, reduction of time and costs, be considered by the project of the system.
increase on the system assurance, performance and Identification of the system stakeholders and
effectiveness, and better satisfaction of customers, users and definition of interests, responsibilities and
producers [1] [4]. authorities.
Definitions about the required system life cycle,
Phases of the SCR: use start date, useful life span, and operation and
The method here presented consists of four steps, where maintenance cycles.
the specialized tasks of systems, requirements and systems • Operational Analysis:
assurance engineering are integrated and executed, as follow: Analysis of the objectives and goals of the
• NRA - Needs and Requirements Analysis operations.
• SCE - Systems Concepts Exploration Description, dimensioning and scenery profiling of
• SCD - System Concept Definition the system mission.
• SRAA - Systems Risks and Assurance Analysis Description of the system operational concepts.
Description and space and time values of the
Purposes of SCR: environmental conditions, during the operations.
As part of the life cycle of projects, the SCR aims to: Architecture concept of the system and
• Create a clear definition about which system concept subsystems, and their space distributions for the
shall be developed, according to which plans and operations.
conditions, to well attend the needs, requirements and Definitions about internal and external interfaces
cost-effectiveness established for the project and among systems and subsystems.
system. Statement of the main expected benefits.

3. ISSN: 1983 7402 ITA, 27 a 30 de setembro de 2011
• Functional Analysis: Evaluation of performance and cost-effectiveness
Description of the system functional concepts and characteristics of each alternative.
requirements: Definition, integration and validation of the
Translation of operational objectives into performance characteristics.
system functions. • Performance Requirements Synthesis:
List and flux of functions (specific, primary Description, classification and qualification of
and secondary). each alternative.
Reasons to exert each function.
Description of why, when, where, duration V. SCD - SYSTEM CONCEPT DEFINITION
and frequency of the functions.
Allocation of functions to the system and Purposes of SCD:
subsystems elements. • Select the best solution of system concept to attend the
Simulation of the functions isolated and combined. established requirements and restrictions.
• Feasibility Definitions: • Select a preferable (most attractive) system concept.
Description, analysis and evaluation of the • Define its basic architecture and functional
currently available solutions. characteristics.
Comparison of the available solutions with the • Develop a detailed plan to the subsequent phases of
system concepts requirements. system and product development, manufacturing and
Evaluation of feasibility of each system functional implementation.
concept.
• Needs Validation: Steps and Tasks of SCD
Characterization and validation of the needs to be • Performance Requirements Analysis:
satisfied, presenting their evidences. Analysis and refinement of the performance and
• Operational Requirements Synthesis: functional requirements.
Elicitation, analysis and validation of all • Functional Analysis and Formulation:
operational requirements and constraints. Definition and simulation of the functional
components.
IV. SCE - SYSTEMS CONCEPTS EXPLORATION Modeling and demonstrations with prototypes of
the alternatives.
Purposes of SCE: • Implementation Concept Selection:
• Present a variety of alternatives as solutions of system Selection and justification of the preferred system
concepts, which will attend the established concept.
requirements and restrictions. • Concept Validation and Description:
• Explore which are the potential concepts of systems Modeling of system concept and its environment.
that may attend the needs. Functional and architectonic specifications of the
• Formulate and validate a set of system performance system concept.
requirements for each of the system concepts. System concept validation and description.
• System Development Planning:
Steps and Tasks of SCE: Planning for the system development, production,
• Operational Requirements Analysis: support, use and discard.
Critical analysis of the operational objectives.
Detailed revision and analysis of the operational VI. SRAA - SYSTEMS RISKS AND ASSURANCE
concept and requirements. ANALYSIS
Feasibility analysis of the operational
requirements. Purposes of SRAA:
• Performance Requirements Formulation: • Assure and validate that the requirements and
Derivation of subsystems functions and restrictions of systems assurance and cost-
performance requirements. effectiveness could be attended by the selected system
Formulation of performance characteristics. concept.
• Implementation Concepts Exploration: • Evaluation of risks and cost-effectiveness.
Assessment and analysis of technologies and • Validation of system assurance requirements.
systems possibilities. • Recommendations for mitigation and control of risks,
Formulation of alternatives of implementation costs and system assurance, for each alternative of
concepts. system concept.
Execution of proof-of-concepts experiments, to • Execute this step in parallel and simultaneously with
evaluate the exequibility of the alternatives. the other three steps of the SCR.
• Performance Requirements Validation:

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Steps and Tasks of SRAA Detailed recommendations for the achievement of
• During the Needs and Requirements Analysis system assurance and cost-effectiveness elements
(NRA): of the selected system concept.
Risks classification and analysis criteria.
Assessment and evaluation of the potential risks VII. CONCLUSIONS
for the project, the system, and the operations.
Assessment, limits characterization, and evaluation The main structure of steps and tasks of the Systems
of the main system assurance requirements, Concepts Research (SCR) method was presented, ready to be
comprising: applied to a general radar project case. As it is a generic
Configuration management, software framework, it will be necessary to adequate the terminology
assurance, rights and penalties of assurance, to each specific application, according to types of systems
verification and validation. and technologies, to apply to other cases.
Quality, reliability, maintainability, safety, The level of details and assessment shall also be tailored
security, human factors, supportability and to each case, in conformance with the degree of uncertainty,
logistics, sustainability, and other analogous. difficulty and newness.
Preliminary evaluation and analysis of the TCO - The four steps of the SCR method comprise the most
Total Cost of Ownership perceived by the market. common tasks recommended for the concept of systems, as
Go-No Go decision. well as to include and integrate the risks, cost-effectiveness
• During the Systems Concepts Exploration (SCE): and assurance disciplines, simultaneous with the systems and
Characterization, evaluation and comparison of requirements engineering tasks.
risks and system assurance parameters of each Taking radar systems as a goal of systems concept, the
alternative of system concept. SCR method will permit a structured and complete analysis
Analysis and evaluation of each trade-off and synthesis, including the flexibility to look for the most
solutions. recent technologies available for radar systems, like the
Analysis of viability of accomplishment of the Software Defined Radio (SDR) technology and method.
system assurance requirements and of the cost-
effectiveness balance. REFERENCES
Go-No Go decision.
Recommendations for the mitigation and control [1] A. Kossiakoff; W. N. Sweet. Systems Engineering - Principles
and Practice. Hoboken, NJ: John Wiley, 2003.
of risks.
[2] S. Blanchard. System Engineering Management. 4th ed.
Recommendations for the provisioning of systems Hoboken, NJ: John Wiley, 2008.
assurance and cost-effectiveness. [3] S. Wasson. System Analysis, Design, and Development -
• During the System Concept Definition (SCD): Concepts, Principles and Practices. Hoboken, NJ: John Wiley,
Detailed analysis and revision of the terms of 2006.
assurance and cost-effectiveness. [4] G. Raheja; A. Allocco. Assurance Technologies Principles and
Practices. 2nd ed. Hoboken, NJ: John Wiley, 2006.
Go-No Go decision.
[5] J. Bogush, Jr. Radar and the Atmosphere. Norwood, MA: Artech
Detailed recommendations for mitigation and House, 1989.
control of risks for the selected system concept.
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