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Tracking Data Cross Support Transfer Service Status. John Pietras 16 October 2008 Berlin. Tracking Data Cross Support Transfer Service. Aimed at “real time” streaming tracking data However, delayed complete delivery also supported Service goals Transfer valid TDM content
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Tracking Data Cross Support Transfer Service Status John Pietras 16 October 2008 Berlin
Tracking Data Cross Support Transfer Service • Aimed at “real time” streaming tracking data • However, delayed complete delivery also supported • Service goals • Transfer valid TDM content • Minimize bandwidth required
DATA_START Record DATA_START Record DATA_START Record Tracking Data Record(s) Tracking Data Record(s) Tracking Data Record(s) Tracking Data Record(s) Tracking Data Record(s) Metadata n Metadata 2 Tracking Data Record(s) DATA_STOP record Tracking Data Record(s) DATA_STOP record NOTIFY ‘data stopped’ NOTIFY ‘metadata updated’ TRANSFER-DATA TRANSFER-DATA Mapping TDM Segment to TD-CSTS Operations TD Operation TDM TDM Partitions Invocations Header Header NOTIFY ‘tdm header’ Header Partition Metadata 1 NOTIFY ‘start time metadata’ Metadata 1 Metadata Partition Data 1 TRANSFER-DATA Data Partition(s) DataStop Partition Metadata Partition Data Partition Data Partition Data Partition Data Partition DataStop Partiton Metadata Partition Data Partition Data Partition Final Partition NOTIFY ‘data stopped’ Metadata 2 NOTIFY ‘metadata updated’ Data 2 TRANSFER-DATA TRANSFER-DATA . . . . . . Data n-1 TRANSFER-DATA TRANSFER-DATA Metadata n Data n . DATA_STOP record NOTIFY ‘data stopped’ NOTIFY ‘end of data’
Issue with Current Approach • TDM parameter names are qualified by the metadata. E.g; • The link is identified in the Metadata • The parameter is named in the Data • If a spacecraft has 2 links (e.g., S and X band) and Transmit Frequency and Receive Frequency are being used concurrently, the metadata has to change for every pair of reported values
Possible Approaches • Repeat metadata for each measurement pair • Fully supported by TDM specification • Higher bandwidth requirements – is this a problem? • Modification to TDM • Modify TDM keywords • E.g., allow multiple indexed PATHs to exist • Let Data keywords reference the indexed PATHs • Allow partial Metadata respecification • Where to apply these modifications? • Part of TDM specification? • TD-CSTS-specific compression? • Run separate TD-CSTS instances for each tracking PATH • Reasonable for separation of radiometric from meteorological data • Not so good for separate RF links
Fundamental Question • How important is minimizing TD-CSTS bandwith?