08- india rcs_std

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REPORT ON THE NEW

IEEE RCS MEASUREMENTSTANDARD

Dr. Eric K. WaltonChairman of the Antenna Standards Committee

IEEE Antennas and Propagation SocietyThe Ohio State UniversityElectroScience Laboratory

1320 Kinnear Road; Columbus, Ohio 43212

ElectroScience Lab

IEEE Recommended Practicefor Radar Cross-Section Test Procedures


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ElectroScience Lab 1

y Introduction to IEEE standards.

What is a standard?

What is the process?

y History of the measurement standard.

y Status of the standard.

Purpose of the standard.

Where are we now?

y Conclusions.



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The new standard is written fory The personnel responsible for the operation of such test ranges

What should they know

What are their responsibilities Basic concepts

Range testing (is it really a plane wave?))

Calibration

Data collection and documentation

Uncertainty analysis and reporting

y For the users of data from such ranges What should they know

What should they expect


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y This talk discusses the RCS measurement standard, IEEEStandards Project P1502.

y This standard (actually a recommended practice) issponsored by the Antenna Standards Committee (ASC) of theIEEE Antennas and Propagation Society (AP-S) (MichaelFrancis, Chair).

y The title is IEEE Recommended Practice For RadarCross-Section Test Procedures.

y The Standard was generated by the Radar Cross SectionSubcommittee of the IEEE AP-S ASC (Dr. Eric Walton, Chair).

y Published on 7 September, 2007

y The document is now available from the IEEE StandardsAssociation as IEEE Standard 1502-2007



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Introduction to IEEE Standards

y What is a standard?

A standard is a published document that sets outspecifications and procedures designed to ensure that amaterial, product, method, or service meets its purposeand consistently performs to its intended use.

y Why are standards necessary and important?

Standards solve issues ranging from product compatibilityto addressing consumer safety and health concerns.

Standards also simplify product development and reducenon-value-adding costs thereby increasing a user's abilityto compare competing products.

They also are fundamental building blocks for internationaltrade.


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What is the Standard Process?

y Project approval

y Develop draft standards

y Ballot draft

y IEEE-SA standards boardapproval

y Publish standard

y Standard Maintenance andReview

Note: This diagram is from the IEEE-SA web site


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For more information on the Process

http://standards.ieee.org/resources/glance.html



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History of the RCS Standard

y The earliest versions of the RCS standards were writtenback in the early 80s by Dr. Eugene Knott.

y This version languished in the files until rewritten byseveral contributors, notably Dr. Robert Dibdall.

y During these days, there were many concerns aboutsecurity of RCS measurements and those in industry andgovernment did not wish to contribute.

y Additionally, many considered their range techniquesand capabilities trade secrets and did not wish tocontribute.



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More Recent History

y During the Defense slowdown of the late 1980s andearly 1990s, the standard project came close toexpiration with IEEESA (A standard can only be

written within an assumed project window or itscharter is withdrawn.).

y To avoid that, the project request was resubmittedon May 20, 1994 and Dr. Eric Walton was appointed

as the Chair of the RCS Standards Subcommittee ofthe IEEE AP-S ASC.

y The new standard project was number P-1502,RCS Measurement Standard Practices.



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y 1502-2007 is a standard practices guide.

Provide recommended practices.

Does not say, thou shall or shall not.

y It is NOT part of the DoD certification processfor RCS measurements.

Does include the essential tenets, such asuncertainty evaluation.

Does recommend process be documented.

This standard should be part of your RangeBook.



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Why a Recommended PracticesVersus a Standard?

y To keep the document to a reasonable length.

y Consideration of the difficult approval cycle for standards.

y Acknowledgement that:

RCS measurements have many goals

There are many ways to make an RCS measurementdepending on the goal of the test.

y Helpful tool for the DoD certification process (Range BookReference).


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Key Events That Occurred During This Time Frame.

y The involvement of the National Institute of Technology(NIST) in RCS measurement uncertainty.

y The completion of the Department of Defense (DoD)demonstration project for range certification.

This provided new life for the project as new members were

recruited and practitioners were more interested indocumenting their procedures so that they could be included,

with references, in their range books.



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A Short, Informal (and perhaps incomplete)List Of Contributors since 1985

Mr. C. Allen,

Dr. D. Bodnar,

Mr. A. Buck,

Dr. R. Dibdall,

Dr. N. Currie,

Dr. J. Davis,

Dr. W. English,

Dr. M. Francis

Prof. S. Gillespie,

Dr. G. Hagn,

Mr. J. Hanfling,

Prof. A. Olver,Dr. W. Parnell,Prof. H. Raemer,

Dr. A. Repjar,

Dr. A. Roederer,

Dr. A. Schell,Dr. G. Tricoles,

Mr. M. Tuley,

Mr. E. A. Urbanik,

Mr. R. Wittmann,

Dr. J. Young.

Dr. R. Hansen,Mr. E. Hart,Dr. D. Hess,Dr. R. Jost,Dr. E. Joy,Prof. W. Kahn

Dr. Brian KentMr. J. Lemanczyk,

Dr. R. Mack,

Dr. D. Mensa,

Dr. L. Muth,

Dr. H. Oltman,


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IEEE APS RCS MEAS STANDARDTABLE OF CONTENTS

1. Overview

2. The RCS Measurement process

1. Background

2. Purpose

3. Standardized Test Procedures3. Measurement Techniques

1. Outdoor & Indoor

2. Plane wave characterization

3. Instrumentation

4. Target support

5. Averaging

4. RCS Imaging Concepts for Measurement

1. Selection of measurement parameters

2. Ambiguities

3. Windowing

5. Organizing RCS range documentation

1. ANSI/NCSL Z-540-1994 overview

2. Organizing the RCS range book

3. Third party certification of range book

6. RCS Uncertainty Analysis

1. Uncertainty vs. error

2. Reporting uncertainty

3. Uncertainty analysis

7. Test Planning8. Summary

* This is a summary, and not a word-for-word TOC


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Outdoor (ground bounce etc.)

Indoor far field

Indoor tapered chamber

FAR FIELD RANGES


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Indoor Compact Ranges of various types


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ERROR TERMS IN RCS RANGES SCANNING OF TEST RANGESFOR SPURIOUS SIGNAL ANDPLANE WAVE ANALYSIS

RANGE ANALYSIS AND CERTIFICATION


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INSTRUMENTATION ISSUES

Linearity andDynamic range Gain imbalance

and offset


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Goal of the Document

y Helpful guide for the RCS measurement practitioner.

y It is not written for the metrologist.

Term removed from the document.

Written for the one making measurements to learn orobserve.

y Document can grow over time if a more rigorous treatment isneeded.


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LESSONS LEARNED

y It is difficult to create a document by a democraticcommittee.

y Volunteers working with a fuzzy deadline on a low

priority project can drag out the process forever.y The editor needs to become a dictator at some point.


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Conclusions

y The IEEE APS ASC Subcomittee on RCS is finallyreleasing a product.

y Upon approval, it will enter into a five year review andupdate cycle.

y The document is now officially available from the

IEEE SA as 1502-2007


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Eric K. WaltonThe Ohio State University ElectroScience Laboratory

Columbus, Ohio 43212

[email protected]; 614/292-5051



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