Skip Ribbon Commands
Skip to main content
SharePoint
Manage PermissionsManage Permissions
|
Version HistoryVersion History

Name of Group

Short Name

Area

Chairperson

Chairperson E-Mail Address

Chairperson Agency

Deputy Chairperson

Deputy Chairperson E-Mail Address

Deputy Chairperson Agency

Mailing List

Scope of Activity

Rationale for Activity

Goals

Survey of Similar Standards Efforts Undertaken in Other Bodies and elsewhere in CCSDS

Patent Licensing Applicability for Future Standards

Technical Risk Mitigation Strategy

Management Risk Mitigation Strategy

Description of Change

Disable Alert

Area Director E-Mail Address

Deputy Area Director E-Mail Address

Create Poll

CC Yourself

Completed/Closed

Approval Status

Attachments

Version:
Created at by
Last modified at by

Manage PermissionsManage Permissions
|
Version HistoryVersion History

Name of Group

1.05 Time Code Formats Working Group

Area

Systems Engineering Area (SEA)

Chairperson

Ed Greenberg

Chairperson E-Mail Address

Edward.Greenberg@jpl.nasa.gov

Chairperson Agency

NASA

Deputy Chairperson

Deputy Chairperson E-Mail Address

Deputy Chairperson Agency

Mailing List

sea-time@mailman.ccsds.org

Scope of Activity

Rationale for Activity

The T-Field of the CCSDS Unsegmented Timecode (CUC) is unnecessarily constrained. The CCSDS recommendation should pose no limit on the number of octets of course or fine time. This view is consistent with the intent and portions of the existing text. The number of seconds is constrained to approximately 136 years while the resolution of subseconds is constrainted to approximately 40 ns.  Current missions such as Project Constellation is asking for the ability to trace mission history beyond the current limit as well as requiring finer resolution than 40 ns.  The current Timecode blue book contains inconsistencies that lead the reader to believe that the CCSDS timecode is constrained to 4 octets of seconds and 3 octets of sub-seconds. However, the only real limitation is that the timecode must be divided into a seconds and sub-seconds sub-fields. Furthermore, as currently stated in the recommendation, the timecode can be self-identified by the use of the P-field or not (in which case, the user must supply metadata outside of the timecode to describe the T-field). It should be noted that no missions have, to our knowledge, ever used the P-field. However, if this field is ever used, it makes sense to extend the P-field to meet the needs of current missions in terms of extending the seconds and sub-seconds fields. In addition, provision is made for a new timecode validation field signifying whether or not the time code is within the limits of the metadata specification or not (i.e., montonically increasing or not).

Goals

The Timecode WG will have the following objectives: 1) Extend the T-field of the CCSDS unsegmented timecode due to missions which require a larger counter to count seconds past the existing capability of approximately 136 years (4 bytes of course time) as well as more resolution of subsection time beyond the current approximately 40 ns resolution (3 bytes of fine time). 2) Extend the P-field of the CCSDS unsegmented timecode to describe the increase in the number of bytes of course and fine time for timecodes which require self-identification. Also provide an indicator in the P-field to signal that a discontinuity in time has occurred.

Survey of Similar Standards Efforts Undertaken in
Other Bodies and elsewhere in CCSDS

Patent Licensing Applicability for Future Standards

BLANK
 

Technical Risk Mitigation Strategy

BLANK

Management Risk Mitigation Strategy

Schedule relies upon at least one other CCSDS Agency joining the effort and on the allocation of adequate Agency resources to the WG. This work involves coordination between SLS area and the SE area.
Version:
Created at by
Last modified at by

Note - To view "Draft" projects, which are not yet approved Click Here.

 Approved Projects

|Export to Spreadsheet|
Currently 1 Projects     
Document Type
Project Status
Project Phase
Modified By
Unsegmented Time code updatesBlueAll Tasks CompletedProject CompletedCCSDS Tech Support