DD CEN ISO/TS 18234-6:2006 - Page 3

Traffic and travel information (TTI). TTI via transport protocol expert group (TPEG) data-streams. Location referencing applications | Status: Current

1 Scope This Technical Specification establishes the method of location referencing used by TPEG applications such as TPEG-RTM or TPEG-PTI. TPEG applications are specified to contain all the information required by a client TPEG decoder (i.e. both location referencing and event information), to present all the information intended for the end-user when it was originated by the service provider. The term "application" is used in TPEG specifications to describe specific applications, which are at the highest layer of the ISO/OSI protocol stack (ISO/IEC 7498-1). Each TPEG application (e.g. TPEG-RTM) is assigned a unique number that is called the Application IDentification (AID). In this respect TPEG-Loc is not an application, but it is an essential constituent part of an application. Location referencing requires a service provider to give an impression or image to the human end-user of where an event has taken place. This cannot be done easily because the human end-user may or may not be familiar with the location. TPEG-Loc has the added challenge of attempting to be as language independent as possible. This is achieved by the use of TPEG-Loc tables (essentially word oriented data object dictionaries). TPEG-Loc also provides location data in a machine-readable form that allows a "thick" client such as a navigation system to map-match, on-the-fly, to locate the event being described onto a digital map display.

NOTE Explicit backwards compatibility with the RDS-TMC location referencing method (EN ISO 14819-3) has NOT been attempted, because RDS-TMC locations are finite in number and must be predetermined. TPEG technology does not suffer from this restriction.