John Pietras

16 October 2008

Berlin

Tracking Data Cross Support Transfer Service Status

2

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

Header

Metadata 1

Data 1

Metadata 2

Data 2

Metadata n

Data n

.

.

.

Header

Metadata 1

.

.

.

Metadata 2

DATA_START RecordTracking Data Record(s)Tracking Data Record(s)

Metadata Partition

Data Partition(s)DataStop Partition

Metadata Partition

Data PartitionData Partition

Data PartitionData PartitionDataStop Partiton

Metadata Partition

Data PartitionData Partition

Final Partition

DATA_START RecordTracking Data Record(s)DATA_STOP record

Metadata n

DATA_START RecordTracking Data Record(s)Tracking Data Record(s)

DATA_STOP record

.

TD OperationTDM TDM Partitions Invocations

Data n-1Tracking Data Record(s)Tracking Data Record(s)

DATA_STOP record

TRANSFER-DATA

NOTIFY‘metadata updated’

TRANSFER-DATA

TRANSFER-DATA

TRANSFER-DATA

TRANSFER-DATATRANSFER-DATA

NOTIFY ‘data stopped’

NOTIFY‘tdm header’Header Partition

NOTIFY‘start time metadata’

NOTIFY ‘data stopped’

NOTIFY‘metadata updated’

NOTIFY ‘data stopped’TRANSFER-DATA

NOTIFY ‘end of data’

Mapping TDM Segment to TD-CSTS Operations

4

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

5

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

6

Fundamental Question

• How important is minimizing TD-CSTS bandwith?