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SAE J2735-Draft-Rev18 [issued: 06-26-07]
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31 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
to be a utility method to be used in developing DSRC applications, and not to be used or depended upon in
real time operational systems because its excessive use by any party would easily disturb time critical
systems by excessive bandwidth consumption.
5.6 Message: MSG_MapFragment
Use: A working summary of the map concepts. Right now this is just an early draft and contains the
concepts needed by the intersection application. In the work by Michael Peredo this outer wrapper is called
the GID layer
ASN.1 Representation:
MapFragment ::= SEQUENCE {
name DescriptiveName OPTIONAL,
layerType LayerType OPTIONAL,
layerID LayerID OPTIONAL,
intersections SEQUENCE (SIZE(0..32)) OF
Intersection OPTIONAL,
-- other objects may be added at this layer, tbd,
-- this might become a nested CHOICE statement
... -- # LOCAL_CONTENT
XML Representation:
<xs:element name="mapFragment" type="MapFragment"/>
<xs:complexType name="MapFragment" >
<xs:sequence>
<xs:element name="name" type="DescriptiveName" minOccurs="0"/>
<xs:element name="layerType" type="LayerType" minOccurs="0"/>
<xs:element name="layerID" type="LayerID" minOccurs="0"/>
<xs:element name="intersections" minOccurs="0">
<xs:complexType>
<xs:sequence minOccurs="0" maxOccurs="32">
<xs:element name="intersection" type="Intersection" />
<!-- other objects may be added at this layer, tbd, this might become
a nested CHOICE statement -->
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="localMapFragment" type="local:MapFragment" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
Remarks: Issues: Not clear how multiple intersections would really be used in this concept. It may be
that complex intersections must be broken down this way. It may be that sending sets of locally nearby
intersections (although each is independent may be the answer).
5.7 Message: MSG_NMEA_Corrections
Use: The NMEA_Corrections message is used to encapsulate NMEA 183 style differential corrections for
GPS radio navigation signals as defined by the NMEA (National Marine Electronics Association)
committee in its Protocol 0183 standard. Here, in the work of DSRC, these messages are "wrapped" for
transport on the DSRC media, and then can be re-constructed back into the final expected formats defined
by the NMEA standard and used directly by GPS positioning systems to increase the absolute and relative
accuracy estimates produced.
ASN.1 Representation:
NMEA-Corrections ::= SEQUENCE {
-- the specific edition of the standard
-- that is being sent, normally 2.0
-- the message and sub-message type, as
-- defined in the revision being used