1 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 A Semantic Data Grid for Satellite Mission Quality Analysis Reuben Wright Deimos Space

2 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Satellite Mission Quality Analysis Semantic Grid development Queries and reports Evaluation Questions Table of contents

3 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 (Very) remote, programmable cameras Plan files converted to Telecommands and sent to Satellite Product data, as Telemetry, sent down from Satellite to Ground Station Data processed in various stages, adding geographical info, interpreting layers, etc Earth Observation

4 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Mission Quality Analysis Satellite Ground Segment consists of: –Mission Planning, Flight Operations, Acquisition Stations, Processing Centres, Archives, Dissemination, and more... –Most interfaces are exchanging files. Mix of binary, Ascii and XML Currently Quality Analysis is carried out by a Monitoring Facility which receives copies of these files Uses a bespoke system called QUARC –Produces many reports comparing planned activity, satellite product acquisions, processing, disseminations, etc... –However, since we are looking for problems, the system would ideally be much more flexible OntoGrid built a Semantic Grid to capture and access the same data

5 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Semantic Data Grid

6 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Semantic Grid Grid system, deployed over Globus toolkit Semantically enabled - S-OGSA architecture. –Grid entities –Knowledge entities –Semantic bindings Semantic Provisioning Services Note that Semantic bindings are “first class citizens” – they have an identity, can have metadata, can be updated Project built semantically aware Grid Services which create, manage and query Semantic Bindings

7 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Annotation Working with –Planning files (to program the satellite) –Product files (data at various processing stages) Onto-DSI extracts the relevant information RDFS Grid Access Bridge provides Satellite Ontology GridKP creates annotations (metadata) Semantic Binding Service manages them System manages updates/overlaps of Plan files. Possible because the metadata is itself an object, with provenance etc Key issue with extracting the metadata from the files is that systems often store it in implicit forms, which we made explicit

8 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 corresponds to: Annotation example Product filename: RA2_MW__1PNPDK _120535_ _00424_20518_0349.N1 "RA2_MW__1PNPDK _120535_ _00424_20518_0349.N1" RA2_MW

9 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 OWL in Space Section of Ontology for Space Systems and Earth Observations

10 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Data Store RDF storage in Atlas Distributed Hash Table indexing, using P2P technology to handle the storage over hundreds of nodes in the Everlab cluster Single point for querying systems. SeRQL, RQL and SPARQL interfaces We produced sets of web forms, to replicate some typical queries needed for reporting

11 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Semantic queries Instruments are explicitly modelled in the RDF so we can move from a query about the Radar Altimeter based on an identifier: ?EVENT event_id ?EVENT_ID ; FILTER ( REGEX(?EVENT_ID,".*RA.*")) To one explicitly looking for a link to the instrument: ?EVENT event_id ?EVENT_ID ; represents_plan_event ?PLAN_EVENT_TYPE. ?PLAN_EVENT_TYPE executed_by_instrument ?INSTRUMENT. ?INSTRUMENT instrument_id "RA" Simple change, but much more flexible if we have new event types for the instrument, or add more data about it (like power consumption)

12 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Creating new report types 1/3 JSP based system of forms for report designer

13 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Creating new report types 2/3 They also identify the user input fields and the output desired

14 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Creating new report types 3/3 User is presented with web form Results generated

15 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Problems Grid, and DHT technologies were complicated to set up Many legacy data formats, and specific data types Missions have similar interfaces and files, but often with small customisations Inertia – much easier to introduce these ideas for new systems

16 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Advantages: Process Integration of data solved well by use of Ontology Separation of concerns, between modelling and domain experts Semantic level of metadata acquisition and querying means virtually no end user training needed Service based architecture – ease of collaborative development and potential for virtual organisations

17 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Advantages: Results Flexible querying of data from hetereogeneous sources All access is virtualised from the user perspective Support for Data and Metadata lifecycles Clear demonstration for industry that standardising and exposing metadata makes the data much more useful

18 DMS-DQS-SUPSC03-PRE-12-E © DEIMOS Space S.L., 2007 Questions Thanks for listening. Any Questions?