The following is a brief overview of each section of AS6969™
1. Scope
The scope defines the scope, purpose, limitations, and viewpoint of AS6969™.
AS6969™ provides definitions for quantities, measurement units, reference systems, measurands, measurements and quantity modalities commonly used on the command and control of cyber physical systems.
The AS6969™ may be used in the development and cross-comparison of data models and in general system and software engineering. The data dictionary can also be extended by users through the creation of quantity domains. The standard is concerned with state data exchanged during the operational activities of cyber physical systems. It is not concerned with system design specifications or parameters. The standard is not concerned with the specific datatypes or classes in a data model.
2. References
AS6969™ is based on and is fully conformant to ISO/IEC 80000, Quantities and units. It also conforms to JCGM 100:2008, Evaluation of measurement data – Guide to the expression of uncertainty in measurement.
3. Definitions and Mathematical Symbols
Section 3 provides foundational definitions concerning numbers; quantities; measurement units; scalars, vectors, and tensors; statistical quantities; measurements; and quantity modalities. It also provides the mathematical symbols for each quantity defined in section 5.
4. Overview of Quantities
The overview provides a foundational explanation of numbers; quantities; cardinal quantities; ordinal quantities; nominal properties; measurement units; scalars, vectors, and tensors; spatial coordinate systems; spatial coordinate reference systems; coordinate operations; statistical quantities; time reference systems; measurements; quantity modalities; and quantity domains.
A quantity domain is an extension to AS6969™. Guidance on developing definition tables for quantity domains is therefore provided.
5. Quantities
This section identifies the defining elements for cardinal quantities and ordinal quantities. It proceeds to provide definition tables for basic quantities relating to: space and time; mechanics; thermodynamics; electromagnetism; light; acoustics (growth); physical chemistry and molecular physics; atomic and nuclear physics; characteristic numbers (growth); solid state physics (growth); and information science and technology. Each table is provided a UUID.
6. Measurement Units
This section identifies the defining elements for measurement units and then provides definition tables (with UUIDs) for: the measurement unit of one and related units; SI measurements units; US customary units; and off-system measurement units.
7. Time Reference Systems
This section identifies different kinds of time reference systems and then provides definition tables (with UUIDs) for: International Atomic Time, Universal Time, Coordinated Universal Time, GPS Time, Galileo System Time, and GLONASS Time.
8. Spatial Reference Systems
This section identifies the defining elements and subtypes of coordinate datums, coordinate systems, and coordinate reference systems. The coordinate datum subtypes are terrestrial reference frame, earth-fixed local tangent plane, vehicle-carried local tangent plane, and engineering body (including vehicle body). Coordinate datum tables required for navigation and vehicle kinematics are provided (with UUIDs).
The coordinate system subtypes are Cartesian, cylindrical, spherical, spherical (range/azimuth/elevation), and ellipsoidal, for which definition tables are provided (with UUIDs).
The subtypes of coordinate reference system are (based on the coordinate datum anchor) (1) earth-centered earth-fixed, geodetic ellipsoid, geoid, map projection; (2) earth-fixed local tangent plane; (3) vehicle-carried local tangent plane; and (4) vehicle body. The required coordinate reference system definition tables for navigation and vehicle kinematics are provided (with UUIDs).
9. Quantity Modalities
Unless otherwise stated, a quantity value is understood in AS6969™ to mean the observable value at that instant. No a-priori or empirical knowledge is assumed for how the value is expected to vary with time or what values are possible/necessary or obligatory/permitted. Where clarification is required, this is called the categorical value. A categorical value is objectively true or false at that instant through measurement.
A quantity modal is a logical or mathematical operator that modifies the semantics of the quantity value to convey information about resource capabilities, mission objectives and tasks, and populations of sampled values.
A modality is a system of related modals. Four modalities are currently defined in AS6969™. These are alethic, deontic, metrological, and waveform.
10. Notes
The notes provide supplemental information on data model considerations and how changes will be indicated in future revisions.