XML in CCSDS CCSDS Spring Meeting - Montreal GMVSA 4081/04 Fran Martínez 2004/05/13

ODM to XML (XODM) conversion Contents Introduction to XML Description Pros and cons XML tools OrbitML ODM to XML (XODM) conversion Requirements and description Tool architecture Conclusions Coming developments Tracking Attitude Page 2 2004/05/13

Introduction to XML 2004/05/13

eXtensible Mark-up Language Implementation Introduction to XML eXtensible Mark-up Language Implementation Tags : <name> … </name> Attributes : <name attrib=“value”> Used for data representation Hierarchy Structure Qualification No format Definition and verification DTD Schema www.w3c.org Page 4 2004/05/13

Hierarchy Introduction to XML Page 5 <stateVector> <time>2006-06-03T00:00:00.000</time> <position> <X>6655.9942</X> <Y>-40218.5751</Y> <Z>-82.9177</Z> </position> <velocity> <VX>3.11548208</VX> <VY>0.47042605</VY> <VZ>-0.00101495</VZ> </velocity> </stateVector> Page 5 2004/05/13

Structure Introduction to XML Page 6 <eventsFile> <timeSpan> <start>2001-12-17T09:30:47-05:00</start> <end>2001-12-17T09:30:47-05:00</end> </timeSpan> <eventsRecord> <time>2001-12-17T09:30:47-05:00</time> <satelliteId>String</satelliteId> <name>String</name> <description>String</description> </eventsRecord> … </eventsFile> Page 6 2004/05/13

Qualification Introduction to XML Page 7 <stateVector frame="TOD”> <time scale="UTC" format="calendar"> 2006-06-03T00:00:00.000 </time> <position units="km"> <X>6655.9942</X> <Y>-40218.5751</Y> <Z>-82.9177</Z> </position> <velocity units="km/s"> <VX>3.11548208</VX> <VY>0.47042605</VY> <VZ>-0.00101495</VZ> </velocity> </stateVector> Page 7 2004/05/13

No format Introduction to XML Page 8 X = 6655.9942 Y = -40218.5751 <stateVector> <time>2006-06-03T00:00:00.000</time> <position> <X>6655.9942</X> <Y>-40218.5751</Y> <Z>-82.9177</Z> </position> <velocity> <VX>3.11548208</VX> <VY>0.47042605</VY> <VZ>-0.00101495</VZ> </velocity> </stateVector> X = 6655.9942 Y = -40218.5751 Z = -82.9177 X_DOT = 3.11548208 Y_DOT = 0.47042605 Z_DOT = -0.00101495 <stateVector><time>2006-06-03T00:00:00.000</time><position><X>6655.9942</X><Y>-40218.5751</Y><Z>-82.9177</Z></position><velocity><VX>3.11548208</VX><VY>0.47042605</VY><VZ>-0.00101495</VZ></velocity></stateVector> Page 8 2004/05/13

Advantages Disadvantages Data structuring and organisation Introduction to XML Advantages Data structuring and organisation Extended in many fields Generic tools Innovative developments Generalised validation mechanisms Easy data transport with qualifiers Object orientation Disadvantages Storage overhead Not human readable format Page 9 2004/05/13

DTD Document structure Defines items and sequences Introduction to XML DTD Document structure Defines items and sequences Validation of syntax only <!ELEMENT stateVector (time, position, velocity)> <!ATTLIST stateVector frame CDATA #REQUIRED > <!ELEMENT time (#PCDATA)> <!ATTLIST time scale CDATA #REQUIRED format CDATA #REQUIRED comment CDATA #REQUIRED <!ELEMENT position (X, Y, Z)> <!ATTLIST position units CDATA #REQUIRED Page 10 2004/05/13

Schema Defines document abstract structure Validation of semantics XML Introduction to XML Schema Defines document abstract structure Validation of semantics XML <xs:complexType name="stateVectorType"> <xs:sequence> <xs:element name="time" type="dateTimeType"/> <xs:element name="position" type="positionType"/> <xs:element name="velocity" type="velocityType"/> </xs:sequence> <xs:attribute name="frame" type="frameType" use="optional" default="J2000"/> </xs:complexType> <xs:complexType name="positionType"> <xs:element name="X" type="lengthMagnitude"/> <xs:element name="Y" type="lengthMagnitude"/> <xs:element name="Z" type="lengthMagnitude"/> <xs:attribute name="units" type="lengthUnits" use="optional" default="m"/> Page 11 2004/05/13

Parsing tools Visualisation tools Validation tools xerces Introduction to XML Parsing tools xerces DOM SAX Implementation in C++, Java, Tcl, … Visualisation tools Web navigators CSS XSLT Validation tools DTD Schema Page 12 2004/05/13

OrbitML 2004/05/13

OrbitML Spacecraft Flight Dynamics Mark-up Language Covers the whole s/c FD spectrum, including: Orbit and attitude determination & prediction Events generation Geodetic Applications Navigation Handles related concepts Satellites, transponders, ground stations, physical models, ... Object (Data) oriented approach Page 14 2004/05/13

OrbitML is a rich source of FD metadata Design drivers Heritage from European FD packages … … improved consistency and portability Readability Extensibility to other space applications OrbitML is a rich source of FD metadata Data model hierarchy through XML data typing through XML Schema … … extended by OrbitML Data relationship basic by XML and Schema … Page 15 2004/05/13

ODM to XML Conversion Tool 2004/05/13

ODM to XML Conversion Tool Requirements ODM  XML notation Analysis of ODM Translation into XML (XODM) XML structured data (data tree) Investigation of conversion tool Approach Analysis of ODM data structures Definition of the XML approach Existing tools Existing supporting elements (OrbitML) Definition of the XODM structures Prototype demonstration Page 17 2004/05/13

ODM to XML Conversion Tool Tool generation rationale Isolate memory structures from data format representations (ODM & XODM) Perform validation of input files Common mapping to memory for both file representations Data structure sharing Bi-directional reading/writing Object oriented approach XML/Schema  UML  C++ Low level items reuse Tools for scanning and parsing xerces-c/SAX for XODM lex + yacc for ODM Page 18 2004/05/13

ODM to XML Conversion Tool Page 19 2004/05/13

ODM to XML Conversion Tool OPM Data Structure Page 20 2004/05/13

ODM to XML Conversion Tool OEM Data Structure Page 21 2004/05/13

ODM to XML Conversion Tool ODM Parser Architecture Page 22 2004/05/13

ODM to XML Conversion Tool Xerces/SAX Architecture Example Page 23 2004/05/13

ODM to XML Conversion Tool Tool generation conclusions Easy translation of data elements to XML Portable C++ (linux, windows, solaris) Full definition through Schema Proven reuse of OrbitML low level items Schema C++ data representation XODM integrated in OrbitML Difficulties Format vs. Data structure Insertion of comments (ambiguities) ODM fixed units vs. XODM attributes Page 24 2004/05/13

Coming Developments 2004/05/13

CCSDS Approach Procedure To come next Coming Developments CCSDS Approach For already analysed elements (ODM) For items to be processed Procedure Same as for ODM (?) Existing formats/structures Newly defined structures (directly in XML) Define procedure Analysis Definition of structures Identification of reusable items To come next Tracking Attitude Page 26 2004/05/13

Coming Developments Page 27 OrbitML observation file type structure 2004/05/13

Coming Developments Page 28 OrbitML attitude file type structure 2004/05/13