


Network Working Group                                     H. Schulzrinne
Internet-Draft                                                  V. Singh
Intended status:  Standards Track                    Columbia University
Expires:  September 27, 2010                               H. Tschofenig
                                                  Nokia Siemens Networks
                                                              M. Thomson
                                                      Andrew Corporation
                                                          March 26, 2010


  Dynamic Extensions to the Presence Information Data Format Location
                            Object (PIDF-LO)
                 draft-singh-geopriv-pidf-lo-dynamic-09

Abstract

   The Geopriv Location Object introduced by the Presence Information
   Data Format - Location Object (PIDF-LO), RFC 4119, defines a basic
   XML format for carrying geographical information of a presentity.
   This document defines PIDF-LO extensions to convey information about
   moving objects.  Elements are defined that enable expression of
   spatial orientation, speed, and heading of the presentity.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on September 27, 2010.

Copyright Notice




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   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Dynamic Elements . . . . . . . . . . . . . . . . . . . . . . .  3
     3.1.  Angular Measures and Coordinate Reference Systems  . . . .  6
   4.  Dynamic Feature XML Schema . . . . . . . . . . . . . . . . . .  8
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  9
     6.1.  Dynamic Feature Extensions Namespace Registration  . . . .  9
     6.2.  Dynamic Feature Extensions Schema Registration . . . . . . 10
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 11
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 11
   Appendix A.  Earth Centered, Earth Fixed Direction Vectors . . . . 11
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12




















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1.  Introduction

   The Presence Information Data Format - Location Object (PIDF-LO) (see
   RFC 4119 [RFC4119]) provides geographical location of a presentity.
   This corresponds to a physical location at a given instance of time.
   With the extensions defined in [RFC5491] more guidelines to
   implementers are being provided with respect to the expression
   location information in PIDF-LO.

   The addition of rate of change information to the PIDF-LO enables a
   range of use cases.  These use cases either directly use dynamic
   information, or use that information for smoother tracking of a
   position over time.  For example, an application that continuously
   tracks a presentity could use velocity information to extrapolate
   positions in between times location information is measured.  A
   shipping company could directly use speed to monitor delivery truck
   speed to ensure speed limits are observed.


2.  Terminology

   In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
   and "OPTIONAL" are to be interpreted as described in RFC 2119
   [RFC2119].

   This document uses the term "presentity", as defined in in RFC 2778
   [RFC2778], through the document to refer to the device subject to
   location determination.  The similarity with presence concepts and
   the abstract location privacy architecture, as described in RFC 4079
   [RFC4079]), lead to re-use of the Presence Information Data Format
   (PIDF), see RFC 3863 [RFC3863], and its enhancement for location
   information with RFC 4119 [RFC4119].  Note that this document does
   not differentiate between human and non-human objects and hence both
   are in scope.


3.  Dynamic Elements

   This document defines a new element, <Dynamic>, for the conveyance of
   dynamic information.

   Dynamic information MAY be included without any other location
   information being present.  When dynamic information is associated
   with information about the instantaneous position of the presentity,
   the <Dynamic> element MUST be included in the same <location-info>
   element as the corresponding geodetic (or civic) location
   information.



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   Dynamic information can be safely ignored by a recipient that does
   not support this specification.

   The <Dynamic> element contains the following components:
   orientation:

      The <orientation> element describes the spatial orientation of the
      presentity; the direction that the object is pointing.  For a
      device, this orientation might depend on the type of device.  See
      Section 3.1 for details.

   speed:

      Speed is the time rate of change in position of a presentity
      without regard for direction; the scalar component of velocity.
      The value for the <speed> element is a measure that is defined in
      meters per second.

   heading:

      Heading is directional component of velocity.  See Section 3.1 for
      details.





























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   Each element can be omitted if no information is available.  In the
   following example the presentity is approximately oriented to the
   North at a slightly elevated angle.  The presentity is travelling 24
   meters per second to the West:

   <?xml version="1.0" encoding="UTF-8"?>
   <presence
       xmlns="urn:ietf:params:xml:ns:pidf"
       xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"
       xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
       xmlns:dyn="urn:ietf:params:xml:ns:pidf:dynamic"
       xmlns:gml="http://www.opengis.net/gml"
       entity="pres:alice@example.com">
       <dm:device id="abc123">
           <gp:geopriv>
               <gp:location-info>
                   <dyn:Dynamic>
                       <dyn:orientation>-3 12</dyn:orientation>
                       <dyn:speed>24</dyn:speed>
                       <dyn:heading>278</dyn:heading>
                   </dyn:Dynamic>
               </gp:location-info>
               <gp:usage-rules/>
               <method>gps</method>
           </gp:geopriv>
           <timestamp>2009-06-22T20:57:29Z</timestamp>
           <dm:deviceID>mac:1234567890ab</dm:deviceID>
       </dm:device>
   </presence>






















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   Another example shows a PIDF-LO document of the presentity
   alice@example.com on a bike traveling 12 meters per second.  Her
   position is indicated as a circle.  The values for speed may be used
   by a receiver to adjust the uncertainty over time.

   <?xml version="1.0" encoding="UTF-8"?>
   <presence
       xmlns="urn:ietf:params:xml:ns:pidf"
       xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"
       xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
       xmlns:dyn="urn:ietf:params:xml:ns:pidf:dynamic"
       xmlns:gml="http://www.opengis.net/gml"
       xmlns:gs="http://www.opengis.net/pidflo/1.0"
       entity="pres:alice@example.com">
       <dm:device id="abc123">
           <gp:geopriv>
               <gp:location-info>
                   <gs:Circle srsName="urn:ogc:def:crs:EPSG::4326">
                       <gml:pos>42.5463 -73.2512</gml:pos>
                       <gs:radius uom="urn:ogc:def:uom:EPSG::9001">
                           100
                       </gs:radius>
                   </gs:Circle>
                   <dyn:Dynamic>
                       <dyn:speed>12</dyn:speed>
                   </dyn:Dynamic>
               </gp:location-info>
               <gp:usage-rules/>
               <method>gps</method>
           </gp:geopriv>
           <timestamp>2009-06-22T20:57:29Z</timestamp>
           <dm:deviceID>mac:1234567890ab</dm:deviceID>
       </dm:device>
   </presence>

3.1.  Angular Measures and Coordinate Reference Systems

   [RFC5491] constrains the coordinate reference system (CRS) used in
   PIDF-LO to World Geodetic System 1984 (WGS 84) using either the two-
   dimensional (latitude, longitude) CRS identified by
   "urn:ogc:def:crs:EPSG::4326" or the three-dimensional (latitude,
   longitude, altitude) CRS identified by "urn:ogc:def:crs:EPSG::4979".
   Dynamic locations similarly assume that either of these coordinate
   reference systems are used.

   The <orientation> and <heading> elements both describe a direction.
   The <orientation> element describes the "direction of facing"; the
   <heading> element describes the "direction of travel".  Both measures



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   contain one or two angular values that are expressed relative to the
   current position of the presentity (see Appendix A).  Angular
   measures are expressed in degrees and values can be negative.  If two
   measures are present, the values MUST be separated by whitespace.

   The first measure specifies the horizontal direction from the current
   position of the presentity to a point that it is pointing towards
   (for <orientation>) or travelling towards (for <heading>).
   Horizontal angles are measured from Northing to Easting.  Horizontal
   angles start from zero when pointing to or travelling towards the
   North and increase towards the East.

   The second measure, if present, specifies the vertical component of
   this angle.  This angle is the elevation from the local horizontal
   plane.  If the second angle value is omitted, the vertical component
   is unknown.  If only one angle is present, <orientation> describes
   only the horizontal component.  For <heading>, the associated <speed>
   measure contains only the horizontal component of speed.

































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4.  Dynamic Feature XML Schema

   <?xml version="1.0"?>
   <xs:schema
       targetNamespace="urn:ietf:params:xml:ns:pidf:dynamic"
       xmlns:dyn="urn:ietf:params:xml:ns:pidf:dynamic"
       xmlns:xs="http://www.w3.org/2001/XMLSchema"
       elementFormDefault="qualified"
       attributeFormDefault="unqualified">

     <xs:element name="Dynamic" type="dyn:dynamicType"/>

     <xs:complexType name="dynamicType">
       <xs:complexContent>
         <xs:restriction base="xs:anyType">
           <xs:sequence>
             <xs:element name="orientation" minOccurs="0"
                         type="dyn:directionType"/>
             <xs:element name="speed" minOccurs="0"
                         type="xs:double"/>
             <xs:element name="heading" minOccurs="0"
                         type="dyn:directionType"/>
             <xs:any namespace="##other" processContents="lax"
                     minOccurs="0" maxOccurs="unbounded"/>
           </xs:sequence>
           <xs:anyAttribute namespace="##other" processContents="lax"/>
         </xs:restriction>
       </xs:complexContent>
     </xs:complexType>

     <xs:simpleType name="directionType">
       <xs:restriction base="dyn:doubleListType">
         <xs:minLength value="1"/>
         <xs:maxLength value="2"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="doubleListType">
       <xs:list itemType="xs:double"/>
     </xs:simpleType>

   </xs:schema>


5.  Security Considerations

   This document defines additional location elements carried by
   PIDF-LO.  These additional elements provide greater reason to observe



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   the privacy and security considerations described in RFC 4119
   [RFC4119].  No further privacy or security measures are necessary.

   RFC 4119 points back to RFC 3694 [RFC3694] and RFC 3693 [RFC3693] to
   describe the threat model and the security requirements imposed on
   the GEOPRIV architecture for sharing location information as result
   of the threat model.  It is important to note that these two
   documents often refer to threats related to the current location
   information of a presentity, while this document introduces dynamic
   information that may be used by attackers to anticipate the future
   location of a presentity.  While already a series of location
   snapshots is likely to offer information for guessing the future
   location of a presentity it has to be said that including more
   information in a PIDF-LO does increase the severity of an information
   leak.  Those who deploy location based services are in general
   strongly advised to provide their users with ways to control the
   distribution of location information to those who have been
   authorized to see it.


6.  IANA Considerations

   This section registers a new XML namespace (as described in
   [RFC3688]) and a new XML schema.

6.1.  Dynamic Feature Extensions Namespace Registration

   URI:  urn:ietf:params:xml:ns:pidf:dynamic"

   Registrant Contact:  IETF Geopriv Working Group, Hannes Tschofenig
      (hannes.tschofenig@gmx.net).

   XML:


















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   BEGIN
   <?xml version="1.0"?>
   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
     "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
   <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
     <title>Dynamic Feature Extensions Namespace</title>
   </head>
   <body>
     <h1>Namespace for Dynamic Feature Extensions to PIDF-LO</h1>
     <h2>urn:ietf:params:xml:ns:pidf:dynamic</h2>
   <p>See <a href="[URL of published RFC]">RFCXXXX
       [NOTE TO IANA/RFC-EDITOR:
        Please replace XXXX with the RFC number of this
       specification.]</a>.</p>
   </body>
   </html>
   END

6.2.  Dynamic Feature Extensions Schema Registration

   URI:  urn:ietf:params:xml:schema:pidf:dynamic

   Registrant Contact:  IETF Geopriv Working Group, Hannes Tschofenig
      (hannes.tschofenig@gmx.net)

   XML:  The XML schema to be registered is contained in Section 4.  Its
      first line is

   <?xml version="1.0"?>

      and its last line is

   </xs:schema>


7.  Acknowledgements

   We would like to thank Klaus Darilion, Cullen Jennings, Rohan Mahy,
   Carl Reed, and Brian Rosen for their comments.  Furthermore, we would
   like to thank Alexey Melnikov, Adrian Farrel, Tim Polk, Dan Romascanu
   for his IESG review comments, Avshalom Houri for his Gen Art review,
   Hilarie Orman for her SECDIR review, and Joel Jaeggli for his
   Operations Directorate review.


8.  References




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8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [RFC4119]  Peterson, J., "A Presence-based GEOPRIV Location Object
              Format", RFC 4119, December 2005.

8.2.  Informative References

   [GeoShape]
              Thomson, M. and C. Reed, "GML 3.1.1 PIDF-LO Shape
              Application Schema for use by the Internet Engineering
              Task Force (IETF)", Candidate OpenGIS Implementation
              Specification 06-142, Version: 0.0.9, December 2006.

   [RFC2778]  Day, M., Rosenberg, J., and H. Sugano, "A Model for
              Presence and Instant Messaging", RFC 2778, February 2000.

   [RFC3693]  Cuellar, J., Morris, J., Mulligan, D., Peterson, J., and
              J. Polk, "Geopriv Requirements", RFC 3693, February 2004.

   [RFC3694]  Danley, M., Mulligan, D., Morris, J., and J. Peterson,
              "Threat Analysis of the Geopriv Protocol", RFC 3694,
              February 2004.

   [RFC3863]  Sugano, H., Fujimoto, S., Klyne, G., Bateman, A., Carr,
              W., and J. Peterson, "Presence Information Data Format
              (PIDF)", RFC 3863, August 2004.

   [RFC4079]  Peterson, J., "A Presence Architecture for the
              Distribution of GEOPRIV Location Objects", RFC 4079,
              July 2005.

   [RFC5491]  Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
              Presence Information Data Format Location Object (PIDF-LO)
              Usage Clarification, Considerations, and Recommendations",
              RFC 5491, March 2009.


Appendix A.  Earth Centered, Earth Fixed Direction Vectors

   The absolute orientation or heading of a presentity depends on its
   latitude and longitude.  The following vectors can be used to
   determine the absolute direction in the WGS 84 Earth Centered, Earth



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   Fixed (X, Y, Z) coordinate space.

   The direction of North as a unit vector in ECEF coordinates is:

      North = [ -1 * sin(latitude) * cos(longitude),
                -1 *  sin(latitude) * sin(longitude),
                cos(latitude) ]

   The direction of "up" (the upward normal of the horizontal plane) as
   a unit vector in ECEF coordinates is:

      Up = [ cos(latitude) * cos(longitude),
             cos(latitude) * sin(longitude),
             sin(latitude) ]


Authors' Addresses

   Henning Schulzrinne
   Columbia University
   Department of Computer Science
   450 Computer Science Building, New York, NY  10027
   US

   Phone:  +1 212 939 7004
   Email:  hgs@cs.columbia.edu
   URI:    http://www.cs.columbia.edu/


   Vishal Singh
   Columbia University
   Department of Computer Science
   450 Computer Science Building, New York, NY  10027
   US

   Email:  vs2140@cs.columbia.edu
   URI:    http://www.cs.columbia.edu/~vs2140














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   Hannes Tschofenig
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  02600
   Finland

   Phone:  +358 (50) 4871445
   Email:  Hannes.Tschofenig@gmx.net
   URI:    http://www.tschofenig.priv.at/


   Martin Thomson
   Andrew Corporation
   Wollongong
   NSW Australia

   Email:  martin.thomson@andrew.com


































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