2 © 2015 Open Geospatial Consortium
For devices such as Radars, a geometric representation of a model may often provide a level of fidelity which is insufficient or inappropriate for use in simulation or alternately, it may not be
feasible to compute a radar cross-section RCS of the model in real-time. Alternately, a user may wish to incorporate real-world RCS data into the simulator client-devices in order to further
improve simulation fidelity. To this end, the CDB Specification defines a RCS Radar Cross- Section model representation for use by Sensor Simulation client-devices such as Radar andor
Sonar. Chapter 7, CDB Radar Cross Section RCS Models establishes a set of conventions that permit RCS representations using the Shapefile format.
The CDB Specification relies heavily on five established industry formats, namely the TIFF format Appendix B, the OpenFlight format Appendix C, the RGB format Appendix P, the
Shapefile format Appendix D and the JPEG 2000 file format Appendix T. These Specifications have been included as appendices to this Specification. Each of these documents
has been annotated to reflect the conventions established by the CDB Specification. The conventions define how TIFF, OpenFlight, RGB, Shapefile and JPEG 2000 formatted files are to
be interpreted by CDB-compliant simulator readers.
Appendices E and F provide the CDB light type naming hierarchy and the CDB model component hierarchies respectively while Appendix L provides the material list for the CDB
Specification.
Other Appendices further describes other aspects of the CDB Specifications like providing the CDB Directory Naming and Structure Appendix M, the mapping of FACC Codes Appendix
N, the List of Texture Component Selectors Appendix O, the SGI Image File Format Appendix P, the Table of Dataset Codes Appendix Q or how some datasets are derived from
others Appendix R.
1.3 Scope
The Specification defines an earth synthetic environment data model and the representation, organization, storage structure and conventions necessary to support all of the subsystems of a
full-mission simulator. The Specification makes use of several commercial and simulation data formats endorsed by leaders of the database tools industry.
The CDB synthetic environment is a representation of the natural environment including external features such as man-made structures and systems. It encompasses the terrain relief, terrain
imagery, three-dimensional 3D models of natural and man-made cultural features, 3D models of vehicles, the ocean surface, and the ocean bottom, including features both natural and man-
made on the ocean floor. In addition, the synthetic environment includes the specific attributes of the synthetic environment data as well as their relationships.
A database that conforms to the CDB Specification i.e., a CDB contains datasets organized in layers, tiles and levels-of-detail; together, these datasets represent the features and models of a
synthetic environment for the purposes of distributed simulation applications. The organization of the synthetic environmental data in a CDB is specifically tailored for real-time applications.
3 © 2015 Open Geospatial Consortium
1.3.1 What is the CDB Specification
The CDB Specification is an open synthetic environment database Specification to which the U.S. Government has unrestricted rights. The CDB Specification is rooted in a group of formats
well established within the simulation industry. To each of these formats, the CDB Specification provides a comprehensive set of conventions appropriate to the field of simulation. The
Specification defines all aspects of data representation and organization, storage structure to support full-mission simulation. A database that conforms to the CDB Specification i.e., a
CDB contains datasets organized in layers and tiles that represent the features of a synthetic environment for the purposes of distributed simulation applications. A CDB can be readily used
by existing simulation client-devices legacy IGs, Radars, CGF, etc. through a publishing process performed in real-time. The data structures used in CDB Specification synthetic
environment databases are different than those used in relational databases mostly because the CDB has chosen to standardize on formats adopted by the simulation community. This
facilitates the work required to adapt existing authoring tools to readwritemodify the CDB and the task to develop runtime publishers RTP designed to operate on these data structures.
The CDB Specification is fundamentally about: 1. A representation of the natural earth and man-made synthetic environment for
the field of simulation. 2. A turnkey, as-is representation of the Synthetic Environment SE for use in
real-time distributed simulation. The synthetic environment is a representation of the natural environment at a specific
geographical location including the external features of the man-made structures and systems. Therefore, the synthetic environment includes the terrain, the terrain features both natural and
man-made, three-dimensional 3D models of vehicles, the ocean surface, and the ocean bottom, including features both natural and man-made on the ocean floor. In addition, the synthetic
environment includes the specific attributes of the synthetic environment data as well as their relationships. The CDB Specification is more than just a means of creating visual aka out-the-
window scenery. Unlike other Specifications that only deal with data representational types of polygons, colors, and textures, it deals with all the data representational types needed in high-end
virtual and constructive simulation applications.
The bulk of the CDB internal data representation is based on five commercial data formats endorsed by leaders of the simulation database tools industry, namely:
TIFFGeoTIFF: for the representation of terrain altimetry, terrain surface characteristics relevant to simulation.
OpenFlight: for the representation of 3D culture and moving models. RGB: for the textures associated with 3D culture and moving models.
Shapefile: for the instancing and attribution of statically positioned point, lineal and areal 2D3D culture features.
