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SAE J2735-Draft-Rev28 [issued: 11-10-08]
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96 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
7. Data Elements
Messages and data frames specified in Clauses 5 and 6 shall be composed of message elements. Any
message or data frame specified in Clauses 6 or 7 shall have all of its DEs specified in this clause, except
those DEs that are primitive ASN.1 data types or those that are adopted from other functional areas, or
defined in other volumes of the family of standards. In the later cases, the referenced standards shall be
consulted.
Regarding equivalent entries to be placed into a data registry. The mapping between data elements and
analogous meta data entries have been explained in other ITS stds. In addition, some meta information is
constant in this entire standard and need not be repeated with each entry here. These include the sponsor
and steward of the entries [SAE], the registration status [registered once the standard is adopted] and the
revision date [the date of the standards adoption]. The class name is always ITS.
The productions of ASN.1 which follow shall be considered normative in nature. While the majority of the
normative content is reflected in the actual syntax of the ASN.1 some entries also have additional
statements in the ASN.1 comments which shall be considered to be normative as well. In addition, the
commentary provided with each entry may also provide additional normative restrictions on the proper use
of the entry which shall be followed. The XML productions follow directly from the ASN.1 specifications
and the same rules shall be applied.
7.1 Data Element: DE_Acceleration
Use: A data element representing the signed acceleration of the vehicle along some known axis in units of
0.01 meters per second squared. A range of over 2Gs is supported. Accelerations in the directions of
forward and to the right are taken as positive. A 2 byte long value when sent.
Longitudinal acceleration is the acceleration along the X axis or the vehicle's direction of travel in parallel
with a front to rear centerline. Negative values indicate braking action.
Lateral acceleration is the acceleration along the Y axis or perpendicular to the vehicle's direction of travel
in parallel with a left-to right centerline. Negative values indicate left turning action and positive values
indicate right-turning action.
ASN.1 Representation:
Acceleration ::= INTEGER (-2000..2000) -- LSB units are 0.01 m/s^2
XML Representation:
<xs:simpleType name="Acceleration" >
<xs:annotation>
<xs:documentation>
LSB units are 0.01 m/s^2
</xs:documentation>
</xs:annotation>
<xs:restriction base="xs:short">
<xs:minInclusive value="-2000"/>
<xs:maxInclusive value="2000"/>
</xs:restriction>
</xs:simpleType>
Used By: This entry is used directly by one other data structure in this standard, a DF called
DF_VehicleStatus <ASN> <XML>. In addition, this item may be used by data structures in other ITS
standards.