Spatial Reference Model SRM Product Development Group PDG

1
Spatial Reference Model (SRM) Product Development
Group (PDG)

• 21 September 2000
• Kevin Trott
• kevin_trott_at_partech.com

2
What is a Spatial Reference Model?

• A Spatial Reference Model is a well-defined set
  of
• spatial reference frames, made up of
• object (especially Earth) reference models, and
• coordinate systems,
• that allows locations to be specified succinctly,
  and
• converted accurately and efficiently between
  different spatial reference frames.

The degree of accuracy and efficiency required
is generally application-dependent.
3
Why is a Spatial Reference Model needed?

• The MS community has not always been consistent
  in its use of models of the earth and related
  coordinate systems.
• Consistency is necessary for distributed
  simulation in order to achieve a level playing
  field and meaningful VVA.
• An SRM is needed to promote lossless, accurate,
  and consistent coordinate transformation results.
• Approximations in coordinate transformation
  algorithms made to reduce processing time may
  introduce additional inconsistencies.
• Nomenclature inconsistency develops without an
  SRM
• Example altitude, elevation, height, geodetic
  height, ellipsoidal height, orthometric height,
  height above sea level, terrain height,...

4
Not Just Location

• The key in MS is not so much where you are, but
  who and what you can interact with
• A complete SRM must address
• Vector and matrix transformation
• Direction (azimuth and elevation angle)
• Range
• (support for) Geometric intervisibility
• Gravity (and implied slope pitch/roll)
• Conversions between common spatial reference
  frames do not necessarily preserve all of these!!!

5
SRM Requirements

• Completeness
• Must include coordinate systems in common usage.
• Must tie these together into a common framework.
• Must educate the system developer.
• Accuracy
• Generally higher than required for C4ISR systems.
• Typically better than 1 cm. up past
  geosynchronous orbit.
• Performance
• Never fast enough!
• Many environmental data sets dominated by
  location data.
• Federate costs for distributed simulation using
  heterogeneous coordinate systems can be
  substantial (e.g., 20 or more).

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SEDRIS-Related ISO/IEC Standards

• The following standards are being developed by
  ISO/IEC Joint Technical Committee 1 (JTC 1)
  Information technology, Sub-committee 24 (SC 24)
  Computer graphics and image processing, Working
  Group 8 (WG 8) Environmental representation
• WD 18023 SEDRIS  DRM, Read Write APIs, STF
• WD 18024 SEDRIS Language Bindings
• WD 18025 Environmental Data Coding Specification
  (EDCS)
• WD ????? EDCS Language Bindings
• WD 18026 Spatial Reference Model (SRM)
• WD ????? SRM Language Bindings
• The US counterpart of SC 24 is the American
  National Standards Institute, National Committee
  for Information Technology Standards, Committee
  H3 (Imagery and Graphics) (ANSI NCITS H3)
• SISO has established a formal relationship with
  ANSI which allows it to participate in the
  standards development process

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SRM PDG Purpose

• To review SRM technologies and software
  implementation
• To provide comments, modifications, improvements,
  for incorporation into the draft ISO/IEC SRM
  standards
• The ISO/IEC SRM standards only provide a
  specification, not an actual implementation
• To develop SRM-based SISO products, recommending,
  encouraging, and supporting its use within the
  MS community
• These products will reference the ISO/IEC SRM
  standards, and will include a reference
  implementation

8
Value to SISO Community

• Leverage an existing SEDRIS technology across a
  broader domain than just environmental data
  representation and interchange
• Any MS data including location/orientation
  information
• Non-environmental runtime (e.g., entity
  locations, ranges, etc.)
• Environment runtime (e.g., dynamic environment
  updates)
• Add value to the ISO/IEC standards
• Scoping the recommended uses of the ISO/IEC
  standards within the MS community, including use
  cases
• Extending (or refining) the ISO/IEC standards for
  use within the MS community
• Develop guidance products based on the ISO/IEC
  standards
• Develop reference implementation with supporting
  documentation

9
Value to MS Community

• Increase interoperability
• Consistent coordinate transformation results
  across all SOMs/FOMs
• Support for improved interoperability between MS
  and C4ISR systems
• To increase federate accuracy and performance
• More accurate and efficient coordinate
  transformation
• To provide rational structure for community data
  modeling
• Improved understanding of spatial reference frame
  selection use
• Improved integration of models data from
  multiple sources

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ISO/SISO Development Relationships
Product V.1
Product V.2
SISO Products (Reference Guidance)
Product V.n
SISO Product References Adds MS-specific
Elaborations and Implementation Details
to International Standard
SISO PDG
Difference Assessment Revised Product Draft
Proposed Revisions
. . .
SISO PDG
Product Draft V.n1
SISO Proposed Extensions (via TAD to
National Standards bodies)
ISO Draft
International Standard
Draft International Standard (DIS)
Committee Draft (CD)
Working Draft (WD)
Final Committee Draft (FCD)
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PDG Membership Status

• Technical Area Director
• Gene Wiehagen, STRICOM
• PDG Officers
• Chair Kevin Trott, PAR Government Systems Corp.
• Vice Chair / Secretary Guy Schiavone, IST
• Drafting Group Comments on Draft ISO/IEC SRM
  Standards
• Paul Berner, SEDRIS Core Team
• Durwood Gafford, LMIS
• Guy Schiavone, IST
• Kevin Trott, PAR Government Systems Corp. (Acting
  DG Editor)
• Membership As of September 2000, 50 individuals
  had subscribed to the SRM PDG reflector

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SRM PDG Resources

• SRM PDG E-Mail Reflector
• SAC-PDG-SRM_at_itcenter.org
• SRM PDG Web Page
• http//confs.itcenter.org/listprocedu/index.cfm?li
  stSAC-PDG-SRM
• Documents available
• Product Nomination Proposal Spatial Reference
  Model (SRM), Version 1.0
• Simulation Interoperability Standards
  Organization Standards Activity Committee,
  Standard and Guidance Development Process,
  Product Development, Draft, 21 January 2000
• Simulation Interoperability Standards
  Organization (SISO) Policies Procedures,
  Version 2.0, 14 December 1999
• SEDRIS Standards and Products Development, Dr.
  Paul A. Birkel, Farid Mamaghani, 30 March 2000
• Spatial Reference Model Overview, March 2000
• Spatial Reference Model Tutorial, August 2000

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PDG Meetings

• March, 2000 (Spring SIW, Orlando) Formation of
  the SRM PDG announced, reflectors and web site
  established, solicitations for members
• 5 May, 2000 (SEDRIS Associates Meeting, ANL)
  Officer elections, products identified, first
  drafting group formed
• 21 September, 2000 (Fall SIW, Orlando) Plan
  review of forthcoming SRM Working Draft(s),
  refine product definitions, establish additional
  drafting groups, review SRM tutorial material

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PDG Accomplishments

• Established and executed election procedures
  Modified guidance found in (draft) PDG Handbook
  describing voting rules for general PDG business
  and comment resolution (section 6, page 5)
• Process announced on reflector, comments
  solicited
• Two-week open self-nomination period (via
  reflector)
• In-person self nominations at first meeting
• Members present vote at first meeting
• Two week review period via reflector
• Results submitted to SAC for approval

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PDG Accomplishments

• (2) SRM PDG Products Identified
• Comments on Draft ISO/IEC SRM Standards
  (Reference)
• Spatial Reference Model (SRM) abstract
  specification
• SRM Language Bindings C
• Drafting Group formed
• Recommended Use of SRM Standards (Guidance?)
• SRM Implementation (Implementation?)
• Source Code and/or Object Library
• (Re)Use Guide  How to (re)use the implementation
• Programmers Guide  Architecture, Algorithms,
  etc.
• Tutorial/Detailed Guidance The SRM Textbook
• Test Plan/Procedures conformance with standards

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PDG Accomplishments

• (3) SRM standard Working Drafts not yet available
  for review, so focus thus far has been on
  educating PDG membership
• May 2000 SRM Overview distributed to membership
  in May for review comment no comments
  received
• September 2000 Updated expanded SRM Tutorial
  distributed to membership for review comment
  one set of comments posted so far
• October 2000 SRM Working Drafts expected will
  be distributed to membership for review comment
  comments will be collected, integrated, and
  provided to SISO in time for Nov/Dec (?) WG8
  meeting

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Meeting Objectives

• Review SRM PDG activities to date
• Review the SISO - ISO/IEC relationship relevant
  to SRM product development
• Review July ISO/IEC WG 8 meeting results and SRM
  Working Draft status
• Establish schedule for review of forthcoming SRM
  WDs
• Refine product descriptions, expand existing
  Drafting Group, and establish additional Drafting
  Groups
• Review and discuss SRM Tutorial material,
  especially need for SRM Data Model (DM) and/or
  Data Representation Model (DRM)