My Feels | Course Paper

Best Practices for Systems

Integration

November 2011

Presented by

Pete Houser

Manager for Engineering & Product Excellence

Northrop Grumman Corporation

Systems Integration Definition

•Systems Integration (SI) is one aspect of the Systems Engineering, Integration, and Test

(SEIT) process. SI must be integrated within the overall SEIT structure.

•Systems Integration is the process of:

–Assembling the constituent parts of a system in a logical, cost-effective way,

comprehensively checking system execution (all nominal & exceptional paths),

and including a full functional check–out.

•Systems Test is the process of:

–Verifying that the system meets its requirements, and

–Validating that the system performs in accordance with the customer/user expectations

•Across Dod Programs, systems integration experiences have been erratic (at best). In many

cases:

–Programs do not define dedicated Integration Engineers.

–Immature system is passed to the Test organization for concurrent Integration and Test.

–Program budget is exceeded because Integration was not separately estimated.

Systems Integration Issues

•When executed as a distinct process, Systems Integration has historically followed the “big bang” model shown

below.

–All of the components arrive more–or-less simultaneously (usually late) in the Integration Lab.

–The Integration engineers arrive more–or-less simultaneously then try to make each piece work.

–Test gets the system when everything is working, or delivery minus – 1 day, whichever comes first.

•Many symptoms illustrate that this process is flawed:

–Integration starts late because of late components, resulting in a flawed and immature delivery.

–Integration is expected to occur instantaneously, feeding an abbreviated and incomplete Test process, in order to

recover schedule and meet the delivery deadline.

–Focus is on components rather than system capabilities;

the Integration team rarely understands the overall system concepts.

–Integration starts when the hardware and software are ready,

so it uses the delivered hardware and software for all activities.

Collect required

hardware

Integrate

hardware

platform

Compile and

link software

sub-systems

Integrate

software on

target hardware

Interface

testing

System

testing

Stress

testing

System testing

Acceptance

testing

Problems require new

design and development

Recommended Process Changes

1. Adopt a Continuous Integration model rather than a Big Bang Integration model.

Establish an Integration rhythm that is essentially independent of the development team.

2. Manage system integration and system test based upon subsystems that can be end-to-end tested against system level

requirements; manage system design & development based upon components that can be independently developed and

checked.

3. Create a Systems Integration team of Responsible Engineers that knows the entire system and follows the program from

Requirements Definition through Acceptance Testing and Operations. Design and Test engineers provide required support

to REs during integration.

4. Create a System Architecture Skeleton (SAS) very early in the program and use it as the framework for Subsystem

Integration as components are added incrementally

5. Define a Configuration Management process such that the System Integration and Configuration Management Teams build

and control the hardware & software configurations.

6. Develop component and subsystem specifications to the extent that they are needed

in order to define component checkout & subsystem verification procedures.

7. Perform component-level checkout to satisfy Integration entry criteria.

8. Track integration progress based upon completing subsystems that have been

verified end-to-end against system-level requirements.

9. Continuously perform regression testing; create internal and/or external automated test tools that greatly reduce the

emphasis on man-in-the-loop testing.

10. Augment requirements-driven testing with stress testing and long mission threads testing in order to promote a robust

system.

1: Continuous Integration Model

Create SAS

Build

Integrate

Test

Build

Integrate

Test

Build

Integrate

Test

Build

Integrate

Test

Build

Integrate

Test

Build

Integrate

Test

Acceptance Test

Develop

& Fab

HW Item

Develop

& Fab

HW Item

Develop

& Fab

HW item

Develop

& Fab

HW Item

Develop

& Fab

HW Item

Develop

SW item

Develop

SW Item

Develop

SW Item

Purchase

Item

Purchase

Item

Purchase

Item

Subsystem #1

integrated Subsystem #2

integrated

Subsystem #3

integrated

Build

Integrate

Test

Full System

Integration

2: Increased Subsystem Emphasis

•A subsystem is an end-to-end functional thread through the system that

satisfies a set of system-level requirements for capabilities and performance.

•A subsystem corresponds to a subset of the overall system physical

implementation.

Subsys A Subsys B Subsys C SubsysD SubsysE

HWCI 1 X X X X X

HWC 1.1 X X X X X

HWC 1.2 X X X X X

HWCI 2 X X X X

HWC 2.1 X X X X

HWC 2.2 X X X X

HWC 2.3 X X X X

HWCI 3 X X X

HWC 3.1 X X

HWC 3.2 X X

SWCI 4 X X X X X

SWC 1.2 X X X X X

SWC 1.3 X X X X X

SWCI 5 X

SWCI 2.1 X

SWCI 2.2 X

SWCI 2.3 X

SWCI 2.4 X

SWCI 2.5 X

SWCI 6 X X X

SWCI 7 X X X

SWCI 4.1 X X X

SWCI 4.2 X X X

Hardware / Software Configuration Items & Components

Subsystems

3: System Integration Team Composition

•Sys Integ Team should be composed of Responsible Engineers (REs), each of whom owns one or more subsystems.

• Each RE is responsible for successfully fielding their subsystem’s capabilities.

•RE responsibilities encompass entire program, from System Specification through fielding, including all HW and SW

components and all suppliers.

•System Integration team uses internal Team funding for integration activities, and uses other program funding when

supporting other activities. System Integration also funds engineers who support the System Integration process.

Validate system

requirements

Identify

subsystem

Establish SAS

Establish Build

process

Participate in

operations